merge: branch 'lr/qr-code'

https://gitlab.gnome.org/GNOME/network-manager-applet/merge_requests/45

15 files changed, 2479 insertions, 7 deletions

diff --git a/Makefile.am b/Makefile.am
index d0c43aca..977d640f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -511,7 +511,9 @@ libnma_h_pub = \
 	src/libnma/nma-mobile-providers.h \
 	src/libnma/nma-vpn-password-dialog.h \
 	src/libnma/nma-ui-utils.h \
-	src/libnma/nma-cert-chooser.h
+	src/libnma/nma-cert-chooser.h \
+	src/libnma/nma-bar-code-widget.h \
+	src/libnma/nma-bar-code.h
 
 libnma_c_real = \
 	src/libnma/nma-wifi-dialog.c \
@@ -521,7 +523,13 @@ libnma_c_real = \
 	src/libnma/nma-ui-utils.c \
 	src/libnma/init.c \
 	src/libnma/nma-cert-chooser.c \
-	src/libnma/nma-file-cert-chooser.c
+	src/libnma/nma-file-cert-chooser.c \
+	src/libnma/nma-bar-code-widget.c \
+	src/libnma/nma-bar-code.c
+
+EXTRA_DIST += \
+	src/libnma/qrcodegen.c \
+	src/libnma/qrcodegen.h
 
 libnma_h_priv_real = \
 	src/libnma/nma-cert-chooser-private.h
@@ -713,12 +721,30 @@ src_libnma_tests_cert_chooser_LDADD = \
 	$(LIBNM_LIBS) \
 	src/libnma/libnma.la
 
+check_PROGRAMS_norun += src/libnma/tests/bar-code
+
+src_libnma_tests_bar_code_CPPFLAGS = \
+	$(dflt_cppflags) \
+	$(GLIB_CFLAGS) \
+	$(GTK3_CFLAGS) \
+	$(LIBNM_CFLAGS) \
+	"-I$(srcdir)/shared/" \
+	"-I$(srcdir)/src/libnma" \
+	-Isrc/libnma
+
+src_libnma_tests_bar_code_LDADD = \
+	$(GLIB_LIBS) \
+	$(GTK3_LIBS) \
+	$(LIBNM_LIBS) \
+	src/libnma/libnma.la
+
 EXTRA_DIST += \
 	src/libnma/nma-version.h.in \
 	src/libnma/libnma.pc.in \
 	src/libnma/libnma.ver \
 	src/libnma/wifi.ui \
 	src/libnma/nma-mobile-wizard.ui \
+	src/libnma/nma-bar-code-widget.ui \
 	src/libnma/nma-pkcs11-token-login-dialog.ui \
 	src/libnma/nma-pkcs11-cert-chooser-dialog.ui \
 	src/libnma/nma-vpn-password-dialog.ui \
diff --git a/libnma-docs.xml b/libnma-docs.xml
index 3d7f369a..d4e888dc 100644
--- a/libnma-docs.xml
+++ b/libnma-docs.xml
@@ -52,6 +52,7 @@
     <xi:include href="xml/nma-vpn-password-dialog.xml"/>
     <xi:include href="xml/nma-wifi-dialog.xml"/>
     <xi:include href="xml/nma-cert-chooser.xml"/>
+    <xi:include href="xml/nma-bar-code.xml"/>
   </chapter>
 
   <chapter id="object-tree">
diff --git a/src/applet-dialogs.c b/src/applet-dialogs.c
index 05f24262..ec9e4941 100644
--- a/src/applet-dialogs.c
+++ b/src/applet-dialogs.c
@@ -30,6 +30,7 @@
 
 #include "applet-dialogs.h"
 #include "utils.h"
+#include "nma-bar-code-widget.h"
 
 
 static void
@@ -453,6 +454,33 @@ display_dns_info (const char * const *dns, GtkGrid *grid, int *row)
 }
 
 static void
+_got_wsec_secrets (GObject *source_object, GAsyncResult *res, gpointer user_data)
+{
+	NMRemoteConnection *connection = NM_REMOTE_CONNECTION (source_object);
+	gs_unref_object GtkWidget *data_widget = GTK_WIDGET (user_data);
+	gs_unref_variant GVariant *secrets = NULL;
+	NMSettingWirelessSecurity *s_wsec;
+
+	secrets = nm_remote_connection_get_secrets_finish (connection, res, NULL);
+	if (!secrets)
+		return;
+
+	if (!nm_connection_update_secrets (NM_CONNECTION (connection),
+	                                   NM_SETTING_WIRELESS_SECURITY_SETTING_NAME,
+	                                   secrets,
+	                                   NULL)) {
+		return;
+	}
+
+	s_wsec = nm_connection_get_setting_wireless_security (NM_CONNECTION (connection));
+	if (!s_wsec)
+		return;
+
+	gtk_label_set_text (GTK_LABEL (data_widget),
+	                    nm_setting_wireless_security_get_psk (s_wsec));
+}
+
+static void
 info_dialog_add_page (GtkNotebook *notebook,
                       NMConnection *connection,
                       NMDevice *device)
@@ -468,11 +496,15 @@ info_dialog_add_page (GtkNotebook *notebook,
 	NMIPAddress *def_addr = NULL;
 	NMIPAddress *def6_addr = NULL;
 	const char *gateway;
-	NMSettingIPConfig *s_ip6;
+	NMSettingIPConfig *s_ip;
 	int row = 0;
 	GtkWidget* speed_label, *sec_label, *desc_widget, *data_widget = NULL;
 	GPtrArray *addresses;
 	gboolean show_security = FALSE;
+	gboolean is_hotspot = FALSE;
+	NMSettingWireless *s_wireless;
+	GBytes *ssid = NULL;
+	gs_free char *ssid_utf8 = NULL;
 	AtkObject *desc_object, *data_object = NULL;
 
 	grid = GTK_GRID (gtk_grid_new ());
@@ -599,6 +631,13 @@ info_dialog_add_page (GtkNotebook *notebook,
 	row++;
 
 	/*--- IPv4 ---*/
+	s_ip = nm_connection_get_setting_ip4_config (connection);
+	if (s_ip) {
+		method = nm_setting_ip_config_get_method (s_ip);
+		if (strcmp (method, NM_SETTING_IP4_CONFIG_METHOD_SHARED) == 0)
+			is_hotspot = TRUE;
+	}
+
 	gtk_grid_attach (grid, create_info_group_label (_("IPv4"), FALSE), 0, row, 2, 1);
 	row++;
 
@@ -638,9 +677,12 @@ info_dialog_add_page (GtkNotebook *notebook,
 	row++;
 
 	/*--- IPv6 ---*/
-	s_ip6 = nm_connection_get_setting_ip6_config (connection);
-	if (s_ip6)
-		 method = nm_setting_ip_config_get_method (s_ip6);
+	s_ip = nm_connection_get_setting_ip6_config (connection);
+	if (s_ip) {
+		method = nm_setting_ip_config_get_method (s_ip);
+		if (strcmp (method, NM_SETTING_IP6_CONFIG_METHOD_SHARED) == 0)
+			is_hotspot = TRUE;
+	}
 
 	if (method && strcmp (method, NM_SETTING_IP6_CONFIG_METHOD_IGNORE) != 0) {
 		gtk_grid_attach (grid, create_info_group_label (_("IPv6"), FALSE), 0, row, 2, 1);
@@ -679,6 +721,51 @@ info_dialog_add_page (GtkNotebook *notebook,
 	dns6 = def6_addr ? nm_ip_config_get_nameservers (ip6_config) : NULL;
 	display_dns_info (dns6, grid, &row);
 
+	/* Wi-Fi */
+	if (!NM_IS_DEVICE_WIFI (device))
+		is_hotspot = FALSE;
+	if (is_hotspot) {
+		gtk_grid_attach (grid, gtk_label_new (""), 0, row, 2, 1);
+		row++;
+		gtk_grid_attach (grid, create_info_group_label (_("Hotspot"), FALSE), 0, row, 2, 1);
+		row++;
+
+		s_wireless = nm_connection_get_setting_wireless (connection);
+		ssid = nm_setting_wireless_get_ssid (s_wireless);
+		ssid_utf8 = nm_utils_ssid_to_utf8 (g_bytes_get_data (ssid, NULL), g_bytes_get_size (ssid));
+
+		desc_widget = create_info_label (_("Network"));
+		desc_object = gtk_widget_get_accessible (desc_widget);
+		data_widget = create_info_value (ssid_utf8);
+		data_object = gtk_widget_get_accessible (data_widget);
+		atk_object_add_relationship (desc_object, ATK_RELATION_LABEL_FOR, data_object);
+
+		gtk_grid_attach (grid, desc_widget, 0, row, 1, 1);
+		gtk_grid_attach (grid, data_widget, 1, row, 1, 1);
+		row++;
+
+		if (nm_connection_get_setting_wireless_security (connection)) {
+			desc_widget = create_info_label (_("Password"));
+			desc_object = gtk_widget_get_accessible (desc_widget);
+			data_widget = create_info_value ("\xe2\x80\x94" /* em dash */);
+			data_object = gtk_widget_get_accessible (data_widget);
+			atk_object_add_relationship (desc_object, ATK_RELATION_LABEL_FOR, data_object);
+
+			gtk_grid_attach (grid, desc_widget, 0, row, 1, 1);
+			gtk_grid_attach (grid, data_widget, 1, row, 1, 1);
+			row++;
+
+			nm_remote_connection_get_secrets_async (NM_REMOTE_CONNECTION (connection),
+		                                                NM_SETTING_WIRELESS_SECURITY_SETTING_NAME,
+		                                                NULL,
+		                                                _got_wsec_secrets,
+		                                                g_object_ref (data_widget));
+		}
+
+		gtk_grid_attach (grid, nma_bar_code_widget_new (connection), 0, row, 2, 1);
+		row++;
+	}
+
 	desc_widget = NULL;
 	desc_object = NULL;
 	data_widget = NULL;
diff --git a/src/libnma/libnma.ver b/src/libnma/libnma.ver
index d5fe734a..9b263d9c 100644
--- a/src/libnma/libnma.ver
+++ b/src/libnma/libnma.ver
@@ -103,3 +103,12 @@ libnma_1_8_12 {
 libnma_1_8_20 {
 	nma_wifi_dialog_new_for_secrets;
 } libnma_1_8_12;
+
+libnma_1_8_22 {
+	nma_bar_code_draw;
+	nma_bar_code_get_size;
+	nma_bar_code_get_type;
+	nma_bar_code_new;
+	nma_bar_code_widget_get_type;
+	nma_bar_code_widget_new;
+} libnma_1_8_12;
diff --git a/src/libnma/meson.build b/src/libnma/meson.build
index 879e1b84..d959ec5f 100644
--- a/src/libnma/meson.build
+++ b/src/libnma/meson.build
@@ -36,6 +36,8 @@ install_headers(
 
 gir_sources = [version_header] + cert_chooser_sources + files(
   'init.c',
+  'nma-bar-code-widget.c',
+  'nma-bar-code.c',
   'nma-mobile-providers.c',
   'nma-mobile-wizard.c',
   'nma-ui-utils.c',
diff --git a/src/libnma/nma-bar-code-widget.c b/src/libnma/nma-bar-code-widget.c
new file mode 100644
index 00000000..a34d4c61
--- /dev/null
+++ b/src/libnma/nma-bar-code-widget.c
@@ -0,0 +1,466 @@
+/* nma-bar-code-widget.h - Renderer of a "QR" code
+ *
+ * Lubomir Rintel <lkundrak@v3.sk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public License as
+ * published by the ree Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright 2018, 2019 Red Hat, Inc.
+ */
+
+#include "nm-default.h"
+
+#include <stdint.h>
+
+#include "nma-bar-code.h"
+#include "nma-bar-code-widget.h"
+
+#define CARD_WIDTH_PT 252
+#define CARD_HEIGHT_PT 144
+
+struct _NMABarCodeWidget {
+	GtkBox parent;
+};
+
+struct _NMABarCodeWidgetClass {
+	GtkBoxClass parent_class;
+};
+
+typedef struct {
+	NMConnection *connection;
+	GtkWidget *qr_code;
+	NMABarCode *qr;
+} NMABarCodeWidgetPrivate;
+
+/**
+ * SECTION:nma-bar-code-widget
+ * @title: NMABarCodeWidget
+ *
+ * This is a widget that displays a QR code for a connection suitable for
+ * optical recognition, e.g. scanning on a phone to connect to a hotspot.
+ */
+
+G_DEFINE_TYPE_WITH_CODE (NMABarCodeWidget, nma_bar_code_widget, GTK_TYPE_BOX,
+                         G_ADD_PRIVATE (NMABarCodeWidget))
+
+enum {
+	PROP_0,
+	PROP_CONNECTION,
+
+	LAST_PROP
+};
+
+#define NMA_BAR_CODE_WIDGET_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), \
+                                     NMA_TYPE_BAR_CODE_WIDGET, \
+                                     NMABarCodeWidgetPrivate))
+
+static void
+do_qr_code_draw (GtkDrawingArea *area, cairo_t *cr, int width, int height,
+                 gpointer user_data)
+{
+	NMABarCodeWidgetPrivate *priv = NMA_BAR_CODE_WIDGET_GET_PRIVATE (user_data);
+	int size = nma_bar_code_get_size (priv->qr);
+
+	gtk_widget_set_size_request (priv->qr_code, (size + 2) * 3, (size + 2) * 3);
+
+	cairo_set_source_rgba (cr, 1, 1, 1, 1);
+	cairo_fill (cr);
+	cairo_paint (cr);
+	cairo_set_source_rgba (cr, 0, 0, 0, 1);
+	cairo_scale (cr, (float)width / (size + 2), (float)height / (size + 2));
+	cairo_translate (cr, 1, 1);
+	cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
+	nma_bar_code_draw (priv->qr, cr);
+}
+
+static gboolean
+qr_code_draw (GtkWidget *widget, cairo_t *cr, gpointer user_data)
+{
+	do_qr_code_draw (GTK_DRAWING_AREA (widget), cr,
+	                 gtk_widget_get_allocated_width (widget),
+	                 gtk_widget_get_allocated_height (widget),
+	                 user_data);
+
+	return TRUE;
+}
+
+static char *
+shell_escape (const char *to_escape)
+{
+	GString *string = g_string_sized_new (32);
+	gboolean quote = *to_escape == '\0';
+	const char *c;
+
+	for (c = to_escape; *c; c++) {
+		if (strchr ("$\\\"", *c))
+			g_string_append_c (string, '\\');
+		else if (!g_ascii_isalnum(*c) && !strchr ("@%^+-_[]:", *c))
+			quote = TRUE;
+		g_string_append_c (string, *c);
+	}
+	if (quote) {
+		g_string_append_c (string, '"');
+		g_string_prepend_c (string, '"');
+	}
+	return g_string_free (string, FALSE);
+}
+
+static void
+draw_one (NMABarCodeWidget *self, cairo_t *cr,
+          const char *psk, const char *ssid,
+          const char *nmcli_line1, const char *nmcli_line2)
+{
+	NMABarCodeWidgetPrivate *priv = NMA_BAR_CODE_WIDGET_GET_PRIVATE (self);
+	int size = nma_bar_code_get_size (priv->qr);
+
+	cairo_save (cr);
+
+	cairo_set_line_width (cr, 0.01);
+	cairo_rectangle (cr, 0, 0, CARD_WIDTH_PT, CARD_HEIGHT_PT);
+	cairo_stroke (cr);
+	cairo_translate (cr, 12, 12);
+
+	cairo_save (cr);
+	cairo_scale (cr, (float)84/(float)size, (float)84/(float)size);
+	cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
+	nma_bar_code_draw (priv->qr, cr);
+	cairo_restore (cr);
+
+	cairo_select_font_face(cr, "Sans", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+
+	cairo_move_to (cr, 96, 12);
+	cairo_set_font_size (cr, 12);
+	cairo_show_text(cr, _("Network"));
+
+	cairo_move_to (cr, 96, 30);
+	cairo_set_font_size (cr, 16);
+	cairo_show_text(cr, ssid);
+
+	cairo_select_font_face(cr, "Monospace", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+
+	cairo_move_to (cr, 0, 108);
+	cairo_set_font_size (cr, 10);
+	cairo_show_text(cr, nmcli_line1);
+
+	if (psk) {
+		cairo_select_font_face(cr, "Sans", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+
+		cairo_move_to (cr, 96, 60);
+		cairo_set_font_size (cr, 12);
+		cairo_show_text(cr, _("Password"));
+
+		cairo_move_to (cr, 96, 78);
+		cairo_set_font_size (cr, 16);
+		cairo_show_text(cr, psk);
+
+		cairo_select_font_face(cr, "Monospace", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+
+		cairo_move_to (cr, 24, 120);
+		cairo_set_font_size (cr, 10);
+		cairo_show_text(cr, nmcli_line2);
+	}
+
+	cairo_restore (cr);
+}
+
+static void
+draw_page (GtkPrintOperation *operation, GtkPrintContext *context, int page_nr, gpointer user_data)
+{
+	NMABarCodeWidget *self = NMA_BAR_CODE_WIDGET (user_data);
+	NMABarCodeWidgetPrivate *priv = NMA_BAR_CODE_WIDGET_GET_PRIVATE (self);
+	cairo_t *cr = gtk_print_context_get_cairo_context (context);
+	double width = gtk_print_context_get_width (context);
+	double height = gtk_print_context_get_height (context);
+	int count_x = width / CARD_WIDTH_PT;
+	int count_y = height / CARD_HEIGHT_PT;
+	double spacing_x = (width - (count_x * CARD_WIDTH_PT)) / (count_x + 1);
+	double spacing_y = (height - (count_y * CARD_HEIGHT_PT)) / (count_y + 1);
+	NMSettingWireless *s_wireless;
+	NMSettingWirelessSecurity *s_wsec;
+	gs_free char *nmcli_line1 = NULL;
+	gs_free char *nmcli_line2 = NULL;
+	const char *psk = NULL;
+	GBytes *ssid_bytes;
+	char *ssid;
+	char *tmp;
+	int x, y;
+
+	s_wireless = nm_connection_get_setting_wireless (priv->connection);
+	if (!s_wireless) {
+		nma_bar_code_set_text (priv->qr, NULL);
+		gtk_widget_queue_draw (priv->qr_code);
+		return;
+	}
+
+	ssid_bytes = nm_setting_wireless_get_ssid (s_wireless);
+	g_return_if_fail (ssid_bytes);
+	ssid = nm_utils_ssid_to_utf8 (g_bytes_get_data (ssid_bytes, NULL),
+	                              g_bytes_get_size (ssid_bytes));
+	g_return_if_fail (ssid);
+
+	s_wsec = nm_connection_get_setting_wireless_security (priv->connection);
+	if (s_wsec)
+		psk = nm_setting_wireless_security_get_psk (s_wsec);
+
+	tmp = shell_escape (ssid);
+	nmcli_line1 = g_strdup_printf ("$ nmcli d wifi con %s%s", tmp, psk ? " \\" : "");
+	g_free (tmp);
+
+	if (psk) {
+		tmp = shell_escape (psk);
+		nmcli_line2 = g_strdup_printf ("password %s", tmp);
+		g_free (tmp);
+	}
+
+	for (y = 0; y < count_y; y++) {
+		cairo_save (cr);
+
+		cairo_translate (cr, spacing_x, spacing_y);
+
+		for (x = 0; x < count_x; x++) {
+			draw_one (self, cr, psk, ssid, nmcli_line1, nmcli_line2);
+			cairo_translate (cr, CARD_WIDTH_PT + spacing_x, 0);
+		}
+
+		cairo_restore (cr);
+		cairo_translate (cr, 0, CARD_HEIGHT_PT + spacing_y);
+	}
+}
+
+static gboolean
+link_activated (GtkLabel *label, char *uri, gpointer user_data)
+{
+	NMABarCodeWidget *self = NMA_BAR_CODE_WIDGET (user_data);
+	GtkPrintOperation *print = gtk_print_operation_new ();
+	GtkWidget *window;
+	GError *error = NULL;
+
+	g_return_val_if_fail (strcmp (uri, "nma:print") == 0, FALSE);
+
+	window = gtk_widget_get_ancestor (GTK_WIDGET (self), GTK_TYPE_WINDOW);
+
+	gtk_print_operation_set_n_pages (print, 1);
+	gtk_print_operation_set_use_full_page (print, TRUE);
+	gtk_print_operation_set_unit (print, GTK_UNIT_POINTS);
+	g_signal_connect (print, "draw_page", G_CALLBACK (draw_page), self);
+
+	if (!gtk_print_operation_run (print, GTK_PRINT_OPERATION_ACTION_PRINT_DIALOG,
+	                              window ? GTK_WINDOW (window) : NULL, &error)) {
+		g_printerr ("%s", error->message);
+		g_error_free (error);
+	}
+
+	g_object_unref (print);
+
+	return FALSE;
+}
+
+static void
+string_append_mecard (GString *string, const char *tag, const char *text)
+{
+	const char *p;
+	bool is_hex = TRUE;
+	int start;
+
+	if (!text)
+		return;
+
+	g_string_append (string, tag);
+	start = string->len;
+
+	for (p = text; *p; p++) {
+		if (!g_ascii_isxdigit (*p))
+			is_hex = FALSE;
+		if (strchr ("\\\":;,", *p))
+			g_string_append_c (string, '\\');
+		g_string_append_c (string, *p);
+	}
+
+	if (is_hex) {
+		g_string_insert_c (string, start, '\"');
+		g_string_append_c (string, '\"');
+	}
+	g_string_append_c (string, ';');
+}
+
+static void
+update_qr_code (NMABarCodeWidget *self)
+{
+	NMABarCodeWidgetPrivate *priv = NMA_BAR_CODE_WIDGET_GET_PRIVATE (self);
+	NMSettingWireless *s_wireless;
+	NMSettingWirelessSecurity *s_wsec;
+	const char *key_mgmt = NULL;
+	const char *psk = NULL;
+	const char *type = NULL;
+	GBytes *ssid_bytes;
+	char *ssid;
+	GString *string;
+
+	if (!priv->qr)
+		return;
+
+	s_wireless = nm_connection_get_setting_wireless (priv->connection);
+	if (!s_wireless) {
+		nma_bar_code_set_text (priv->qr, NULL);
+		gtk_widget_queue_draw (priv->qr_code);
+		return;
+	}
+
+	ssid_bytes = nm_setting_wireless_get_ssid (s_wireless);
+	g_return_if_fail (ssid_bytes);
+	ssid = nm_utils_ssid_to_utf8 (g_bytes_get_data (ssid_bytes, NULL),
+	                              g_bytes_get_size (ssid_bytes));
+	g_return_if_fail (ssid);
+
+	string = g_string_sized_new (64);
+	g_string_append (string, "WIFI:");
+
+	s_wsec = nm_connection_get_setting_wireless_security (priv->connection);
+	if (s_wsec) {
+		key_mgmt = nm_setting_wireless_security_get_key_mgmt (s_wsec);
+		psk = nm_setting_wireless_security_get_psk (s_wsec);
+	}
+
+	if (key_mgmt == NULL) {
+		type = "nopass";
+	} else if (   strcmp (key_mgmt, "none") == 0
+	           || strcmp (key_mgmt, "ieee8021x") == 0) {
+		type = "WEP";
+	} else if (   strcmp (key_mgmt, "wpa-none") == 0
+	           || strcmp (key_mgmt, "wpa-psk") == 0) {
+		type = "WPA";
+	}
+
+	string_append_mecard(string, "T:", type);
+	string_append_mecard(string, "S:", ssid);
+	string_append_mecard(string, "P:", psk);
+
+	if (nm_setting_wireless_get_hidden (s_wireless))
+		g_string_append (string, "H:true;");
+
+	g_string_append_c (string, ';');
+	nma_bar_code_set_text (priv->qr, string->str);
+	gtk_widget_queue_draw (priv->qr_code);
+	g_string_free (string, TRUE);
+}
+
+static void
+set_connection (NMABarCodeWidget *self, NMConnection *connection)
+{
+	NMABarCodeWidgetPrivate *priv = NMA_BAR_CODE_WIDGET_GET_PRIVATE (self);
+
+	if (priv->connection) {
+		g_signal_handlers_disconnect_by_data (priv->connection, self);
+		g_clear_object (&priv->connection);
+	}
+
+	if (connection) {
+		priv->connection = connection;
+		g_signal_connect_swapped (connection, "changed", G_CALLBACK (update_qr_code), self);
+		g_signal_connect_swapped (connection, "secrets-updated", G_CALLBACK (update_qr_code), self);
+	}
+}
+
+static void
+get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
+{
+	NMABarCodeWidgetPrivate *priv = NMA_BAR_CODE_WIDGET_GET_PRIVATE (object);
+
+	switch (prop_id) {
+	case PROP_CONNECTION:
+		g_value_set_object (value, priv->connection);
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+		break;
+	}
+}
+
+static void
+set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
+{
+	NMABarCodeWidget *self = NMA_BAR_CODE_WIDGET (object);
+
+	switch (prop_id) {
+	case PROP_CONNECTION:
+		set_connection (self, g_value_dup_object (value));
+		update_qr_code (self);
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+		break;
+	}
+}
+
+static void
+nma_bar_code_widget_init (NMABarCodeWidget *self)
+{
+	NMABarCodeWidgetPrivate *priv = NMA_BAR_CODE_WIDGET_GET_PRIVATE (self);
+
+	gtk_widget_init_template (GTK_WIDGET (self));
+
+	priv->qr = nma_bar_code_new (NULL);
+	g_signal_connect (priv->qr_code, "draw", G_CALLBACK (qr_code_draw), self);
+}
+
+/**
+ * nma_bar_code_widget_new:
+ * @connection: connection to get network details from
+ *
+ * Returns: (transfer full): the bar code widget instance
+ *
+ * Since: 1.8.22
+ */
+GtkWidget *
+nma_bar_code_widget_new (NMConnection *connection)
+{
+	return g_object_new (NMA_TYPE_BAR_CODE_WIDGET,
+	                     NMA_BAR_CODE_WIDGET_CONNECTION, connection,
+	                     NULL);
+}
+
+static void
+finalize (GObject *object)
+{
+	NMABarCodeWidget *self = NMA_BAR_CODE_WIDGET (object);
+	NMABarCodeWidgetPrivate *priv = NMA_BAR_CODE_WIDGET_GET_PRIVATE (self);
+
+	g_clear_object (&priv->qr);
+	set_connection (self, NULL);
+
+	G_OBJECT_CLASS (nma_bar_code_widget_parent_class)->finalize (object);
+}
+
+static void
+nma_bar_code_widget_class_init (NMABarCodeWidgetClass *klass)
+{
+	GObjectClass *object_class = G_OBJECT_CLASS (klass);
+	GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+
+	object_class->get_property = get_property;
+	object_class->set_property = set_property;
+	object_class->finalize = finalize;
+
+	g_object_class_install_property
+		(object_class, PROP_CONNECTION,
+		 g_param_spec_object (NMA_BAR_CODE_WIDGET_CONNECTION, "", "",
+		                      NM_TYPE_CONNECTION,
+		                      G_PARAM_READABLE | G_PARAM_WRITABLE));
+
+	gtk_widget_class_set_template_from_resource (widget_class,
+	                                             "/org/freedesktop/network-manager-applet/nma-bar-code-widget.ui");
+
+	gtk_widget_class_bind_template_child_private (widget_class, NMABarCodeWidget, qr_code);
+	gtk_widget_class_bind_template_callback (widget_class, link_activated);
+}
diff --git a/src/libnma/nma-bar-code-widget.h b/src/libnma/nma-bar-code-widget.h
new file mode 100644
index 00000000..9bd452a9
--- /dev/null
+++ b/src/libnma/nma-bar-code-widget.h
@@ -0,0 +1,47 @@
+/* nma-bar-code.h - Widget that renders a "QR" code
+ *
+ * Lubomir Rintel <lkundrak@v3.sk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public License as
+ * published by the ree Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright (C) 2018, 2019 Red Hat, Inc.
+ */
+
+#ifndef __NMA_BAR_CODE_WIDGET_H__
+#define __NMA_BAR_CODE_WIDGET_H__
+
+#include <glib-object.h>
+
+#include "nma-version.h"
+
+#define NMA_TYPE_BAR_CODE_WIDGET            (nma_bar_code_widget_get_type ())
+#define NMA_BAR_CODE_WIDGET(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), NMA_TYPE_BAR_CODE_WIDGET, NMABarCodeWidget))
+#define NMA_BAR_CODE_WIDGET_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), NMA_TYPE_BAR_CODE_WIDGET, NMABarCodeWidgetClass))
+#define NMA_IS_BAR_CODE_WIDGET(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), NMA_TYPE_BAR_CODE_WIDGET))
+#define NMA_IS_BAR_CODE_WIDGET_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), NMA_TYPE_BAR_CODE_WIDGET))
+#define NMA_BAR_CODE_WIDGET_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), NMA_TYPE_BAR_CODE_WIDGET, NMABarCodeWidgetClass))
+
+#define NMA_BAR_CODE_WIDGET_CONNECTION "connection"
+
+typedef struct _NMABarCodeWidget       NMABarCodeWidget;
+typedef struct _NMABarCodeWidgetClass  NMABarCodeWidgetClass;
+
+NMA_AVAILABLE_IN_1_8_22
+GType       nma_bar_code_widget_get_type (void) G_GNUC_CONST;
+
+NMA_AVAILABLE_IN_1_8_22
+GtkWidget  *nma_bar_code_widget_new (NMConnection *connection);
+
+#endif /* __NMA_BAR_CODE_WIDGET_H__ */
diff --git a/src/libnma/nma-bar-code-widget.ui b/src/libnma/nma-bar-code-widget.ui
new file mode 100644
index 00000000..d88f17c6
--- /dev/null
+++ b/src/libnma/nma-bar-code-widget.ui
@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- Generated with glade 3.22.1 -->
+<interface domain="nm-applet">
+  <requires lib="gtk+" version="3.20"/>
+  <template class="NMABarCodeWidget" parent="GtkBox">
+    <property name="visible">True</property>
+    <property name="can_focus">False</property>
+    <property name="margin_start">6</property>
+    <property name="margin_end">6</property>
+    <property name="margin_top">6</property>
+    <property name="margin_bottom">6</property>
+    <property name="orientation">vertical</property>
+    <property name="spacing">6</property>
+    <child>
+      <object class="GtkAspectFrame">
+        <property name="expand">True</property>
+        <property name="visible">True</property>
+        <property name="can_focus">False</property>
+        <property name="label_xalign">0.5</property>
+        <child>
+          <object class="GtkDrawingArea" id="qr_code">
+            <property name="visible">True</property>
+            <property name="can_focus">False</property>
+          </object>
+        </child>
+      </object>
+      <packing>
+        <property name="position">0</property>
+      </packing>
+    </child>
+    <child>
+      <object class="GtkLabel">
+        <property name="expand">False</property>
+        <property name="visible">True</property>
+        <property name="can_focus">False</property>
+        <property name="label" translatable="yes">Scan with your phone or &lt;a href="nma:print"&gt;Print&lt;/a&gt;</property>
+        <property name="use_markup">True</property>
+        <signal name="activate-link" handler="link_activated" swapped="no"/>
+      </object>
+      <packing>
+        <property name="position">1</property>
+      </packing>
+    </child>
+  </template>
+</interface>
diff --git a/src/libnma/nma-bar-code.c b/src/libnma/nma-bar-code.c
new file mode 100644
index 00000000..5f0f7f22
--- /dev/null
+++ b/src/libnma/nma-bar-code.c
@@ -0,0 +1,226 @@
+/* nma-bar-code.h - Renderer of a "QR" code
+ *
+ * Lubomir Rintel <lkundrak@v3.sk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public License as
+ * published by the ree Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright 2018, 2019 Red Hat, Inc.
+ */
+
+#include "nm-default.h"
+
+#include <stdint.h>
+
+#include "nma-bar-code.h"
+
+/*
+ * The aim of this class is to provide a GObject-y QR code generator based
+ * on qrcodegen library [1].  We purposefully include it directly instead
+ * of compiling it separately, while providing a much less flexible (and
+ * more straightforward) API. This way we the compiler does a good job at
+ * slimming things down (chopping off half of the library) while allowing
+ * us to leave the original source unmodified for easier maintenance.
+ *
+ * [1] https://github.com/nayuki/QR-Code-generator
+ */
+
+#pragma GCC visibility push(hidden)
+NM_PRAGMA_WARNING_DISABLE("-Wdeclaration-after-statement")
+#define NDEBUG
+#include "qrcodegen.c"
+NM_PRAGMA_WARNING_REENABLE
+#pragma GCC visibility pop
+
+struct _NMABarCode {
+	GObject parent;
+};
+
+struct _NMABarCodeClass {
+	GObjectClass parent_class;
+};
+
+typedef struct {
+	uint8_t qrcode[qrcodegen_BUFFER_LEN_FOR_VERSION (qrcodegen_VERSION_MAX)];
+} NMABarCodePrivate;
+
+/**
+ * SECTION:nma-bar-code
+ * @title: NMABarCode
+ *
+ * A Bar Code object provides the means of drawing a QR code onto a cairo
+ * context. Useful for rendering Wi-Fi network credential in a form that
+ * can be optically scanned with a phone camera.
+ */
+
+G_DEFINE_TYPE_WITH_CODE (NMABarCode, nma_bar_code, G_TYPE_OBJECT,
+                         G_ADD_PRIVATE (NMABarCode))
+
+enum {
+	PROP_0,
+	PROP_TEXT,
+	PROP_SIZE,
+
+	LAST_PROP
+};
+
+#define NMA_BAR_CODE_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), NMA_TYPE_BAR_CODE, NMABarCodePrivate))
+
+/**
+ * nma_bar_code_set_text:
+ * @self: bar code instance
+ * @text: new bar code text
+ *
+ * Regenerates the QR code for a different text.
+ *
+ * Since: 1.8.22
+ */
+
+void
+nma_bar_code_set_text (NMABarCode *self, const char *text)
+{
+	g_object_set (self, NMA_BAR_CODE_TEXT, text, NULL);
+}
+
+/**
+ * nma_bar_code_get_size:
+ * @self: bar code instance
+ *
+ * Returns: the side of a QR code square.
+ *
+ * Since: 1.8.22
+ */
+
+int
+nma_bar_code_get_size (NMABarCode *self)
+{
+	int size;
+
+	g_object_get (self, NMA_BAR_CODE_SIZE, &size, NULL);
+	return size;
+}
+
+/**
+ * nma_bar_code_draw:
+ * @self: bar code instance
+ * @cr: cairo context
+ *
+ * Draws the QR code onto the given context.
+ *
+ * Since: 1.8.22
+ */
+
+void
+nma_bar_code_draw (NMABarCode *self, cairo_t *cr)
+{
+	NMABarCodePrivate *priv = NMA_BAR_CODE_GET_PRIVATE (self);
+	int x, y, size;
+
+	size = qrcodegen_getSize (priv->qrcode);
+	cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
+
+	for (y = 0; y < size; y++) {
+		for (x = 0; x < size; x++) {
+			if (qrcodegen_getModule (priv->qrcode, x, y)) {
+				cairo_rectangle (cr, x, y, 1, 1);
+				cairo_fill (cr);
+			}
+		}
+	}
+}
+
+static void
+get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
+{
+	NMABarCodePrivate *priv = NMA_BAR_CODE_GET_PRIVATE (object);
+
+	switch (prop_id) {
+	case PROP_SIZE:
+		g_value_set_int (value, qrcodegen_getSize (priv->qrcode));
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+		break;
+	}
+}
+
+static void
+set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
+{
+	NMABarCodePrivate *priv = NMA_BAR_CODE_GET_PRIVATE (object);
+	uint8_t tempBuffer[qrcodegen_BUFFER_LEN_FOR_VERSION (qrcodegen_VERSION_MAX)];
+	const char *text;
+	bool success = FALSE;
+
+	switch (prop_id) {
+	case PROP_TEXT:
+		text = g_value_get_string (value);
+		if (text) {
+			success = qrcodegen_encodeText(g_value_get_string (value),
+			                               tempBuffer,
+			                               priv->qrcode,
+			                               qrcodegen_Ecc_LOW,
+			                               qrcodegen_VERSION_MIN,
+			                               qrcodegen_VERSION_MAX,
+			                               qrcodegen_Mask_AUTO,
+			                               FALSE);
+		}
+		if (!success)
+			bzero (priv->qrcode, sizeof (priv->qrcode));
+		g_object_notify (object, NMA_BAR_CODE_SIZE);
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+		break;
+	}
+}
+
+static void
+nma_bar_code_init (NMABarCode *self)
+{
+}
+
+/**
+ * nma_bar_code_new:
+ * @text: set the bar code text
+ *
+ * Returns: (transfer full): the bar code instance
+ *
+ * Since: 1.8.22
+ */
+
+NMABarCode *
+nma_bar_code_new (const char *text)
+{
+	return g_object_new (NMA_TYPE_BAR_CODE, NMA_BAR_CODE_TEXT, text, NULL);
+}
+
+static void
+nma_bar_code_class_init (NMABarCodeClass *klass)
+{
+	GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+	object_class->get_property = get_property;
+	object_class->set_property = set_property;
+
+	g_object_class_install_property
+		(object_class, PROP_TEXT,
+		 g_param_spec_string (NMA_BAR_CODE_TEXT, "", "",
+		                      "", G_PARAM_WRITABLE));
+
+	g_object_class_install_property
+		(object_class, PROP_SIZE,
+		 g_param_spec_int (NMA_BAR_CODE_SIZE, "", "",
+		                   G_MININT, G_MAXINT, 0, G_PARAM_READABLE));
+}
diff --git a/src/libnma/nma-bar-code.h b/src/libnma/nma-bar-code.h
new file mode 100644
index 00000000..3cdd9459
--- /dev/null
+++ b/src/libnma/nma-bar-code.h
@@ -0,0 +1,58 @@
+/* nma-bar-code.h - Widget that renders a "QR" code
+ *
+ * Lubomir Rintel <lkundrak@v3.sk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public License as
+ * published by the ree Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright (C) 2018, 2019 Red Hat, Inc.
+ */
+
+#ifndef __NMA_BAR_CODE_H__
+#define __NMA_BAR_CODE_H__
+
+#include <glib-object.h>
+#include <cairo.h>
+
+#include "nma-version.h"
+
+#define NMA_TYPE_BAR_CODE            (nma_bar_code_get_type ())
+#define NMA_BAR_CODE(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), NMA_TYPE_BAR_CODE, NMABarCode))
+#define NMA_BAR_CODE_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), NMA_TYPE_BAR_CODE, NMABarCodeClass))
+#define NMA_IS_BAR_CODE(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), NMA_TYPE_BAR_CODE))
+#define NMA_IS_BAR_CODE_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), NMA_TYPE_BAR_CODE))
+#define NMA_BAR_CODE_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), NMA_TYPE_BAR_CODE, NMABarCodeClass))
+
+#define NMA_BAR_CODE_TEXT "text"
+#define NMA_BAR_CODE_SIZE "size"
+
+typedef struct _NMABarCode       NMABarCode;
+typedef struct _NMABarCodeClass  NMABarCodeClass;
+
+NMA_AVAILABLE_IN_1_8_22
+GType       nma_bar_code_get_type (void) G_GNUC_CONST;
+
+NMA_AVAILABLE_IN_1_8_22
+NMABarCode *nma_bar_code_new (const char *text);
+
+NMA_AVAILABLE_IN_1_8_22
+void        nma_bar_code_set_text (NMABarCode *self, const char *text);
+
+NMA_AVAILABLE_IN_1_8_22
+int         nma_bar_code_get_size (NMABarCode *self);
+
+NMA_AVAILABLE_IN_1_8_22
+void        nma_bar_code_draw (NMABarCode *self, cairo_t *cr);
+
+#endif /* __NMA_BAR_CODE_H__ */
diff --git a/src/libnma/nma-version.h.in b/src/libnma/nma-version.h.in
index ba6af984..c8638a91 100644
--- a/src/libnma/nma-version.h.in
+++ b/src/libnma/nma-version.h.in
@@ -72,9 +72,10 @@
 #define NMA_VERSION_1_8_8  (NMA_ENCODE_VERSION (1, 8, 8))
 #define NMA_VERSION_1_8_10 (NMA_ENCODE_VERSION (1, 8, 10))
 #define NMA_VERSION_1_8_12 (NMA_ENCODE_VERSION (1, 8, 12))
+#define NMA_VERSION_1_8_22 (NMA_ENCODE_VERSION (1, 8, 22))
 
 #define NMA_VERSION_CUR_STABLE  NMA_VERSION_1_8_10
-#define NMA_VERSION_NEXT_STABLE NMA_VERSION_1_8_12
+#define NMA_VERSION_NEXT_STABLE NMA_VERSION_1_8_22
 
 #define NMA_VERSION NMA_ENCODE_VERSION (NMA_MAJOR_VERSION, NMA_MINOR_VERSION, NMA_MICRO_VERSION)
 
@@ -123,4 +124,10 @@
 # define NMA_AVAILABLE_IN_1_8
 #endif
 
+#if NMA_VERSION_MAX_ALLOWED < NMA_VERSION_1_8_22
+# define NMA_AVAILABLE_IN_1_8_22            G_UNAVAILABLE(1.8,22)
+#else
+# define NMA_AVAILABLE_IN_1_8_22
+#endif
+
 #endif  /* NMA_VERSION_H */
diff --git a/src/libnma/nma.gresource.xml b/src/libnma/nma.gresource.xml
index e5f803e7..ee1fcb20 100644
--- a/src/libnma/nma.gresource.xml
+++ b/src/libnma/nma.gresource.xml
@@ -6,5 +6,6 @@
 		<file preprocess="xml-stripblanks">nma-pkcs11-cert-chooser-dialog.ui</file>
 		<file preprocess="xml-stripblanks">nma-mobile-wizard.ui</file>
 		<file preprocess="xml-stripblanks">nma-vpn-password-dialog.ui</file>
+		<file preprocess="xml-stripblanks">nma-bar-code-widget.ui</file>
 	</gresource>
 </gresources>
diff --git a/src/libnma/qrcodegen.c b/src/libnma/qrcodegen.c
new file mode 100644
index 00000000..7cda9659
--- /dev/null
+++ b/src/libnma/qrcodegen.c
@@ -0,0 +1,1009 @@
+/*
+ * QR Code generator library (C)
+ *
+ * Copyright (c) Project Nayuki. (MIT License)
+ * https://www.nayuki.io/page/qr-code-generator-library
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * - The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ * - The Software is provided "as is", without warranty of any kind, express or
+ *   implied, including but not limited to the warranties of merchantability,
+ *   fitness for a particular purpose and noninfringement. In no event shall the
+ *   authors or copyright holders be liable for any claim, damages or other
+ *   liability, whether in an action of contract, tort or otherwise, arising from,
+ *   out of or in connection with the Software or the use or other dealings in the
+ *   Software.
+ */
+
+#include <assert.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include "qrcodegen.h"
+
+#ifndef QRCODEGEN_TEST
+	#define testable static  // Keep functions private
+#else
+	#define testable  // Expose private functions
+#endif
+
+
+/*---- Forward declarations for private functions ----*/
+
+// Regarding all public and private functions defined in this source file:
+// - They require all pointer/array arguments to be not null unless the array length is zero.
+// - They only read input scalar/array arguments, write to output pointer/array
+//   arguments, and return scalar values; they are "pure" functions.
+// - They don't read mutable global variables or write to any global variables.
+// - They don't perform I/O, read the clock, print to console, etc.
+// - They allocate a small and constant amount of stack memory.
+// - They don't allocate or free any memory on the heap.
+// - They don't recurse or mutually recurse. All the code
+//   could be inlined into the top-level public functions.
+// - They run in at most quadratic time with respect to input arguments.
+//   Most functions run in linear time, and some in constant time.
+//   There are no unbounded loops or non-obvious termination conditions.
+// - They are completely thread-safe if the caller does not give the
+//   same writable buffer to concurrent calls to these functions.
+
+testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen);
+
+testable void addEccAndInterleave(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]);
+testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl);
+testable int getNumRawDataModules(int ver);
+
+testable void calcReedSolomonGenerator(int degree, uint8_t result[]);
+testable void calcReedSolomonRemainder(const uint8_t data[], int dataLen,
+	const uint8_t generator[], int degree, uint8_t result[]);
+testable uint8_t finiteFieldMultiply(uint8_t x, uint8_t y);
+
+testable void initializeFunctionModules(int version, uint8_t qrcode[]);
+static void drawWhiteFunctionModules(uint8_t qrcode[], int version);
+static void drawFormatBits(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uint8_t qrcode[]);
+testable int getAlignmentPatternPositions(int version, uint8_t result[7]);
+static void fillRectangle(int left, int top, int width, int height, uint8_t qrcode[]);
+
+static void drawCodewords(const uint8_t data[], int dataLen, uint8_t qrcode[]);
+static void applyMask(const uint8_t functionModules[], uint8_t qrcode[], enum qrcodegen_Mask mask);
+static long getPenaltyScore(const uint8_t qrcode[]);
+static void addRunToHistory(unsigned char run, unsigned char history[7]);
+static bool hasFinderLikePattern(unsigned char runHistory[7]);
+
+testable bool getModule(const uint8_t qrcode[], int x, int y);
+testable void setModule(uint8_t qrcode[], int x, int y, bool isBlack);
+testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isBlack);
+static bool getBit(int x, int i);
+
+testable int calcSegmentBitLength(enum qrcodegen_Mode mode, size_t numChars);
+testable int getTotalBits(const struct qrcodegen_Segment segs[], size_t len, int version);
+static int numCharCountBits(enum qrcodegen_Mode mode, int version);
+
+
+
+/*---- Private tables of constants ----*/
+
+// The set of all legal characters in alphanumeric mode, where each character
+// value maps to the index in the string. For checking text and encoding segments.
+static const char *ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";
+
+// For generating error correction codes.
+testable const int8_t ECC_CODEWORDS_PER_BLOCK[4][41] = {
+	// Version: (note that index 0 is for padding, and is set to an illegal value)
+	//0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40    Error correction level
+	{-1,  7, 10, 15, 20, 26, 18, 20, 24, 30, 18, 20, 24, 26, 30, 22, 24, 28, 30, 28, 28, 28, 28, 30, 30, 26, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30},  // Low
+	{-1, 10, 16, 26, 18, 24, 16, 18, 22, 22, 26, 30, 22, 22, 24, 24, 28, 28, 26, 26, 26, 26, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28},  // Medium
+	{-1, 13, 22, 18, 26, 18, 24, 18, 22, 20, 24, 28, 26, 24, 20, 30, 24, 28, 28, 26, 30, 28, 30, 30, 30, 30, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30},  // Quartile
+	{-1, 17, 28, 22, 16, 22, 28, 26, 26, 24, 28, 24, 28, 22, 24, 24, 30, 28, 28, 26, 28, 30, 24, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30},  // High
+};
+
+#define qrcodegen_REED_SOLOMON_DEGREE_MAX 30  // Based on the table above
+
+// For generating error correction codes.
+testable const int8_t NUM_ERROR_CORRECTION_BLOCKS[4][41] = {
+	// Version: (note that index 0 is for padding, and is set to an illegal value)
+	//0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40    Error correction level
+	{-1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 4,  4,  4,  4,  4,  6,  6,  6,  6,  7,  8,  8,  9,  9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25},  // Low
+	{-1, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5,  5,  8,  9,  9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49},  // Medium
+	{-1, 1, 1, 2, 2, 4, 4, 6, 6, 8, 8,  8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68},  // Quartile
+	{-1, 1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81},  // High
+};
+
+// For automatic mask pattern selection.
+static const int PENALTY_N1 =  3;
+static const int PENALTY_N2 =  3;
+static const int PENALTY_N3 = 40;
+static const int PENALTY_N4 = 10;
+
+
+
+/*---- High-level QR Code encoding functions ----*/
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode[],
+		enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl) {
+
+	size_t textLen = strlen(text);
+	if (textLen == 0)
+		return qrcodegen_encodeSegmentsAdvanced(NULL, 0, ecl, minVersion, maxVersion, mask, boostEcl, tempBuffer, qrcode);
+	size_t bufLen = qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion);
+
+	struct qrcodegen_Segment seg;
+	if (qrcodegen_isNumeric(text)) {
+		if (qrcodegen_calcSegmentBufferSize(qrcodegen_Mode_NUMERIC, textLen) > bufLen)
+			goto fail;
+		seg = qrcodegen_makeNumeric(text, tempBuffer);
+	} else if (qrcodegen_isAlphanumeric(text)) {
+		if (qrcodegen_calcSegmentBufferSize(qrcodegen_Mode_ALPHANUMERIC, textLen) > bufLen)
+			goto fail;
+		seg = qrcodegen_makeAlphanumeric(text, tempBuffer);
+	} else {
+		if (textLen > bufLen)
+			goto fail;
+		for (size_t i = 0; i < textLen; i++)
+			tempBuffer[i] = (uint8_t)text[i];
+		seg.mode = qrcodegen_Mode_BYTE;
+		seg.bitLength = calcSegmentBitLength(seg.mode, textLen);
+		if (seg.bitLength == -1)
+			goto fail;
+		seg.numChars = (int)textLen;
+		seg.data = tempBuffer;
+	}
+	return qrcodegen_encodeSegmentsAdvanced(&seg, 1, ecl, minVersion, maxVersion, mask, boostEcl, tempBuffer, qrcode);
+
+fail:
+	qrcode[0] = 0;  // Set size to invalid value for safety
+	return false;
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode[],
+		enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl) {
+
+	struct qrcodegen_Segment seg;
+	seg.mode = qrcodegen_Mode_BYTE;
+	seg.bitLength = calcSegmentBitLength(seg.mode, dataLen);
+	if (seg.bitLength == -1) {
+		qrcode[0] = 0;  // Set size to invalid value for safety
+		return false;
+	}
+	seg.numChars = (int)dataLen;
+	seg.data = dataAndTemp;
+	return qrcodegen_encodeSegmentsAdvanced(&seg, 1, ecl, minVersion, maxVersion, mask, boostEcl, dataAndTemp, qrcode);
+}
+
+
+// Appends the given number of low-order bits of the given value to the given byte-based
+// bit buffer, increasing the bit length. Requires 0 <= numBits <= 16 and val < 2^numBits.
+testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen) {
+	assert(0 <= numBits && numBits <= 16 && (unsigned long)val >> numBits == 0);
+	for (int i = numBits - 1; i >= 0; i--, (*bitLen)++)
+		buffer[*bitLen >> 3] |= ((val >> i) & 1) << (7 - (*bitLen & 7));
+}
+
+
+
+/*---- Low-level QR Code encoding functions ----*/
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
+		enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]) {
+	return qrcodegen_encodeSegmentsAdvanced(segs, len, ecl,
+		qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, -1, true, tempBuffer, qrcode);
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
+		int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]) {
+	assert(segs != NULL || len == 0);
+	assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
+	assert(0 <= (int)ecl && (int)ecl <= 3 && -1 <= (int)mask && (int)mask <= 7);
+
+	// Find the minimal version number to use
+	int version, dataUsedBits;
+	for (version = minVersion; ; version++) {
+		int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;  // Number of data bits available
+		dataUsedBits = getTotalBits(segs, len, version);
+		if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
+			break;  // This version number is found to be suitable
+		if (version >= maxVersion) {  // All versions in the range could not fit the given data
+			qrcode[0] = 0;  // Set size to invalid value for safety
+			return false;
+		}
+	}
+	assert(dataUsedBits != -1);
+
+	// Increase the error correction level while the data still fits in the current version number
+	for (int i = (int)qrcodegen_Ecc_MEDIUM; i <= (int)qrcodegen_Ecc_HIGH; i++) {  // From low to high
+		if (boostEcl && dataUsedBits <= getNumDataCodewords(version, (enum qrcodegen_Ecc)i) * 8)
+			ecl = (enum qrcodegen_Ecc)i;
+	}
+
+	// Concatenate all segments to create the data bit string
+	memset(qrcode, 0, qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
+	int bitLen = 0;
+	for (size_t i = 0; i < len; i++) {
+		const struct qrcodegen_Segment *seg = &segs[i];
+		appendBitsToBuffer((int)seg->mode, 4, qrcode, &bitLen);
+		appendBitsToBuffer(seg->numChars, numCharCountBits(seg->mode, version), qrcode, &bitLen);
+		for (int j = 0; j < seg->bitLength; j++)
+			appendBitsToBuffer((seg->data[j >> 3] >> (7 - (j & 7))) & 1, 1, qrcode, &bitLen);
+	}
+	assert(bitLen == dataUsedBits);
+
+	// Add terminator and pad up to a byte if applicable
+	int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;
+	assert(bitLen <= dataCapacityBits);
+	int terminatorBits = dataCapacityBits - bitLen;
+	if (terminatorBits > 4)
+		terminatorBits = 4;
+	appendBitsToBuffer(0, terminatorBits, qrcode, &bitLen);
+	appendBitsToBuffer(0, (8 - bitLen % 8) % 8, qrcode, &bitLen);
+	assert(bitLen % 8 == 0);
+
+	// Pad with alternating bytes until data capacity is reached
+	for (uint8_t padByte = 0xEC; bitLen < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
+		appendBitsToBuffer(padByte, 8, qrcode, &bitLen);
+
+	// Draw function and data codeword modules
+	addEccAndInterleave(qrcode, version, ecl, tempBuffer);
+	initializeFunctionModules(version, qrcode);
+	drawCodewords(tempBuffer, getNumRawDataModules(version) / 8, qrcode);
+	drawWhiteFunctionModules(qrcode, version);
+	initializeFunctionModules(version, tempBuffer);
+
+	// Handle masking
+	if (mask == qrcodegen_Mask_AUTO) {  // Automatically choose best mask
+		long minPenalty = LONG_MAX;
+		for (int i = 0; i < 8; i++) {
+			enum qrcodegen_Mask msk = (enum qrcodegen_Mask)i;
+			drawFormatBits(ecl, msk, qrcode);
+			applyMask(tempBuffer, qrcode, msk);
+			long penalty = getPenaltyScore(qrcode);
+			if (penalty < minPenalty) {
+				mask = msk;
+				minPenalty = penalty;
+			}
+			applyMask(tempBuffer, qrcode, msk);  // Undoes the mask due to XOR
+		}
+	}
+	assert(0 <= (int)mask && (int)mask <= 7);
+	drawFormatBits(ecl, mask, qrcode);
+	applyMask(tempBuffer, qrcode, mask);
+	return true;
+}
+
+
+
+/*---- Error correction code generation functions ----*/
+
+// Appends error correction bytes to each block of the given data array, then interleaves
+// bytes from the blocks and stores them in the result array. data[0 : dataLen] contains
+// the input data. data[dataLen : rawCodewords] is used as a temporary work area and will
+// be clobbered by this function. The final answer is stored in result[0 : rawCodewords].
+testable void addEccAndInterleave(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]) {
+	// Calculate parameter numbers
+	assert(0 <= (int)ecl && (int)ecl < 4 && qrcodegen_VERSION_MIN <= version && version <= qrcodegen_VERSION_MAX);
+	int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[(int)ecl][version];
+	int blockEccLen = ECC_CODEWORDS_PER_BLOCK  [(int)ecl][version];
+	int rawCodewords = getNumRawDataModules(version) / 8;
+	int dataLen = getNumDataCodewords(version, ecl);
+	int numShortBlocks = numBlocks - rawCodewords % numBlocks;
+	int shortBlockDataLen = rawCodewords / numBlocks - blockEccLen;
+
+	// Split data into blocks, calculate ECC, and interleave
+	// (not concatenate) the bytes into a single sequence
+	uint8_t generator[qrcodegen_REED_SOLOMON_DEGREE_MAX];
+	calcReedSolomonGenerator(blockEccLen, generator);
+	const uint8_t *dat = data;
+	for (int i = 0; i < numBlocks; i++) {
+		int datLen = shortBlockDataLen + (i < numShortBlocks ? 0 : 1);
+		uint8_t *ecc = &data[dataLen];  // Temporary storage
+		calcReedSolomonRemainder(dat, datLen, generator, blockEccLen, ecc);
+		for (int j = 0, k = i; j < datLen; j++, k += numBlocks) {  // Copy data
+			if (j == shortBlockDataLen)
+				k -= numShortBlocks;
+			result[k] = dat[j];
+		}
+		for (int j = 0, k = dataLen + i; j < blockEccLen; j++, k += numBlocks)  // Copy ECC
+			result[k] = ecc[j];
+		dat += datLen;
+	}
+}
+
+
+// Returns the number of 8-bit codewords that can be used for storing data (not ECC),
+// for the given version number and error correction level. The result is in the range [9, 2956].
+testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl) {
+	int v = version, e = (int)ecl;
+	assert(0 <= e && e < 4);
+	return getNumRawDataModules(v) / 8
+		- ECC_CODEWORDS_PER_BLOCK    [e][v]
+		* NUM_ERROR_CORRECTION_BLOCKS[e][v];
+}
+
+
+// Returns the number of data bits that can be stored in a QR Code of the given version number, after
+// all function modules are excluded. This includes remainder bits, so it might not be a multiple of 8.
+// The result is in the range [208, 29648]. This could be implemented as a 40-entry lookup table.
+testable int getNumRawDataModules(int ver) {
+	assert(qrcodegen_VERSION_MIN <= ver && ver <= qrcodegen_VERSION_MAX);
+	int result = (16 * ver + 128) * ver + 64;
+	if (ver >= 2) {
+		int numAlign = ver / 7 + 2;
+		result -= (25 * numAlign - 10) * numAlign - 55;
+		if (ver >= 7)
+			result -= 36;
+	}
+	return result;
+}
+
+
+
+/*---- Reed-Solomon ECC generator functions ----*/
+
+// Calculates the Reed-Solomon generator polynomial of the given degree, storing in result[0 : degree].
+testable void calcReedSolomonGenerator(int degree, uint8_t result[]) {
+	// Start with the monomial x^0
+	assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX);
+	memset(result, 0, degree * sizeof(result[0]));
+	result[degree - 1] = 1;
+
+	// Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
+	// drop the highest term, and store the rest of the coefficients in order of descending powers.
+	// Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).
+	uint8_t root = 1;
+	for (int i = 0; i < degree; i++) {
+		// Multiply the current product by (x - r^i)
+		for (int j = 0; j < degree; j++) {
+			result[j] = finiteFieldMultiply(result[j], root);
+			if (j + 1 < degree)
+				result[j] ^= result[j + 1];
+		}
+		root = finiteFieldMultiply(root, 0x02);
+	}
+}
+
+
+// Calculates the remainder of the polynomial data[0 : dataLen] when divided by the generator[0 : degree], where all
+// polynomials are in big endian and the generator has an implicit leading 1 term, storing the result in result[0 : degree].
+testable void calcReedSolomonRemainder(const uint8_t data[], int dataLen,
+		const uint8_t generator[], int degree, uint8_t result[]) {
+
+	// Perform polynomial division
+	assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX);
+	memset(result, 0, degree * sizeof(result[0]));
+	for (int i = 0; i < dataLen; i++) {
+		uint8_t factor = data[i] ^ result[0];
+		memmove(&result[0], &result[1], (degree - 1) * sizeof(result[0]));
+		result[degree - 1] = 0;
+		for (int j = 0; j < degree; j++)
+			result[j] ^= finiteFieldMultiply(generator[j], factor);
+	}
+}
+
+#undef qrcodegen_REED_SOLOMON_DEGREE_MAX
+
+
+// Returns the product of the two given field elements modulo GF(2^8/0x11D).
+// All inputs are valid. This could be implemented as a 256*256 lookup table.
+testable uint8_t finiteFieldMultiply(uint8_t x, uint8_t y) {
+	// Russian peasant multiplication
+	uint8_t z = 0;
+	for (int i = 7; i >= 0; i--) {
+		z = (z << 1) ^ ((z >> 7) * 0x11D);
+		z ^= ((y >> i) & 1) * x;
+	}
+	return z;
+}
+
+
+
+/*---- Drawing function modules ----*/
+
+// Clears the given QR Code grid with white modules for the given
+// version's size, then marks every function module as black.
+testable void initializeFunctionModules(int version, uint8_t qrcode[]) {
+	// Initialize QR Code
+	int qrsize = version * 4 + 17;
+	memset(qrcode, 0, ((qrsize * qrsize + 7) / 8 + 1) * sizeof(qrcode[0]));
+	qrcode[0] = (uint8_t)qrsize;
+
+	// Fill horizontal and vertical timing patterns
+	fillRectangle(6, 0, 1, qrsize, qrcode);
+	fillRectangle(0, 6, qrsize, 1, qrcode);
+
+	// Fill 3 finder patterns (all corners except bottom right) and format bits
+	fillRectangle(0, 0, 9, 9, qrcode);
+	fillRectangle(qrsize - 8, 0, 8, 9, qrcode);
+	fillRectangle(0, qrsize - 8, 9, 8, qrcode);
+
+	// Fill numerous alignment patterns
+	uint8_t alignPatPos[7];
+	int numAlign = getAlignmentPatternPositions(version, alignPatPos);
+	for (int i = 0; i < numAlign; i++) {
+		for (int j = 0; j < numAlign; j++) {
+			// Don't draw on the three finder corners
+			if (!((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0)))
+				fillRectangle(alignPatPos[i] - 2, alignPatPos[j] - 2, 5, 5, qrcode);
+		}
+	}
+
+	// Fill version blocks
+	if (version >= 7) {
+		fillRectangle(qrsize - 11, 0, 3, 6, qrcode);
+		fillRectangle(0, qrsize - 11, 6, 3, qrcode);
+	}
+}
+
+
+// Draws white function modules and possibly some black modules onto the given QR Code, without changing
+// non-function modules. This does not draw the format bits. This requires all function modules to be previously
+// marked black (namely by initializeFunctionModules()), because this may skip redrawing black function modules.
+static void drawWhiteFunctionModules(uint8_t qrcode[], int version) {
+	// Draw horizontal and vertical timing patterns
+	int qrsize = qrcodegen_getSize(qrcode);
+	for (int i = 7; i < qrsize - 7; i += 2) {
+		setModule(qrcode, 6, i, false);
+		setModule(qrcode, i, 6, false);
+	}
+
+	// Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules)
+	for (int dy = -4; dy <= 4; dy++) {
+		for (int dx = -4; dx <= 4; dx++) {
+			int dist = abs(dx);
+			if (abs(dy) > dist)
+				dist = abs(dy);
+			if (dist == 2 || dist == 4) {
+				setModuleBounded(qrcode, 3 + dx, 3 + dy, false);
+				setModuleBounded(qrcode, qrsize - 4 + dx, 3 + dy, false);
+				setModuleBounded(qrcode, 3 + dx, qrsize - 4 + dy, false);
+			}
+		}
+	}
+
+	// Draw numerous alignment patterns
+	uint8_t alignPatPos[7];
+	int numAlign = getAlignmentPatternPositions(version, alignPatPos);
+	for (int i = 0; i < numAlign; i++) {
+		for (int j = 0; j < numAlign; j++) {
+			if ((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0))
+				continue;  // Don't draw on the three finder corners
+			for (int dy = -1; dy <= 1; dy++) {
+				for (int dx = -1; dx <= 1; dx++)
+					setModule(qrcode, alignPatPos[i] + dx, alignPatPos[j] + dy, dx == 0 && dy == 0);
+			}
+		}
+	}
+
+	// Draw version blocks
+	if (version >= 7) {
+		// Calculate error correction code and pack bits
+		int rem = version;  // version is uint6, in the range [7, 40]
+		for (int i = 0; i < 12; i++)
+			rem = (rem << 1) ^ ((rem >> 11) * 0x1F25);
+		long bits = (long)version << 12 | rem;  // uint18
+		assert(bits >> 18 == 0);
+
+		// Draw two copies
+		for (int i = 0; i < 6; i++) {
+			for (int j = 0; j < 3; j++) {
+				int k = qrsize - 11 + j;
+				setModule(qrcode, k, i, (bits & 1) != 0);
+				setModule(qrcode, i, k, (bits & 1) != 0);
+				bits >>= 1;
+			}
+		}
+	}
+}
+
+
+// Draws two copies of the format bits (with its own error correction code) based
+// on the given mask and error correction level. This always draws all modules of
+// the format bits, unlike drawWhiteFunctionModules() which might skip black modules.
+static void drawFormatBits(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uint8_t qrcode[]) {
+	// Calculate error correction code and pack bits
+	assert(0 <= (int)mask && (int)mask <= 7);
+	static const int table[] = {1, 0, 3, 2};
+	int data = table[(int)ecl] << 3 | (int)mask;  // errCorrLvl is uint2, mask is uint3
+	int rem = data;
+	for (int i = 0; i < 10; i++)
+		rem = (rem << 1) ^ ((rem >> 9) * 0x537);
+	int bits = (data << 10 | rem) ^ 0x5412;  // uint15
+	assert(bits >> 15 == 0);
+
+	// Draw first copy
+	for (int i = 0; i <= 5; i++)
+		setModule(qrcode, 8, i, getBit(bits, i));
+	setModule(qrcode, 8, 7, getBit(bits, 6));
+	setModule(qrcode, 8, 8, getBit(bits, 7));
+	setModule(qrcode, 7, 8, getBit(bits, 8));
+	for (int i = 9; i < 15; i++)
+		setModule(qrcode, 14 - i, 8, getBit(bits, i));
+
+	// Draw second copy
+	int qrsize = qrcodegen_getSize(qrcode);
+	for (int i = 0; i < 8; i++)
+		setModule(qrcode, qrsize - 1 - i, 8, getBit(bits, i));
+	for (int i = 8; i < 15; i++)
+		setModule(qrcode, 8, qrsize - 15 + i, getBit(bits, i));
+	setModule(qrcode, 8, qrsize - 8, true);  // Always black
+}
+
+
+// Calculates and stores an ascending list of positions of alignment patterns
+// for this version number, returning the length of the list (in the range [0,7]).
+// Each position is in the range [0,177), and are used on both the x and y axes.
+// This could be implemented as lookup table of 40 variable-length lists of unsigned bytes.
+testable int getAlignmentPatternPositions(int version, uint8_t result[7]) {
+	if (version == 1)
+		return 0;
+	int numAlign = version / 7 + 2;
+	int step = (version == 32) ? 26 :
+		(version*4 + numAlign*2 + 1) / (numAlign*2 - 2) * 2;
+	for (int i = numAlign - 1, pos = version * 4 + 10; i >= 1; i--, pos -= step)
+		result[i] = pos;
+	result[0] = 6;
+	return numAlign;
+}
+
+
+// Sets every pixel in the range [left : left + width] * [top : top + height] to black.
+static void fillRectangle(int left, int top, int width, int height, uint8_t qrcode[]) {
+	for (int dy = 0; dy < height; dy++) {
+		for (int dx = 0; dx < width; dx++)
+			setModule(qrcode, left + dx, top + dy, true);
+	}
+}
+
+
+
+/*---- Drawing data modules and masking ----*/
+
+// Draws the raw codewords (including data and ECC) onto the given QR Code. This requires the initial state of
+// the QR Code to be black at function modules and white at codeword modules (including unused remainder bits).
+static void drawCodewords(const uint8_t data[], int dataLen, uint8_t qrcode[]) {
+	int qrsize = qrcodegen_getSize(qrcode);
+	int i = 0;  // Bit index into the data
+	// Do the funny zigzag scan
+	for (int right = qrsize - 1; right >= 1; right -= 2) {  // Index of right column in each column pair
+		if (right == 6)
+			right = 5;
+		for (int vert = 0; vert < qrsize; vert++) {  // Vertical counter
+			for (int j = 0; j < 2; j++) {
+				int x = right - j;  // Actual x coordinate
+				bool upward = ((right + 1) & 2) == 0;
+				int y = upward ? qrsize - 1 - vert : vert;  // Actual y coordinate
+				if (!getModule(qrcode, x, y) && i < dataLen * 8) {
+					bool black = getBit(data[i >> 3], 7 - (i & 7));
+					setModule(qrcode, x, y, black);
+					i++;
+				}
+				// If this QR Code has any remainder bits (0 to 7), they were assigned as
+				// 0/false/white by the constructor and are left unchanged by this method
+			}
+		}
+	}
+	assert(i == dataLen * 8);
+}
+
+
+// XORs the codeword modules in this QR Code with the given mask pattern.
+// The function modules must be marked and the codeword bits must be drawn
+// before masking. Due to the arithmetic of XOR, calling applyMask() with
+// the same mask value a second time will undo the mask. A final well-formed
+// QR Code needs exactly one (not zero, two, etc.) mask applied.
+static void applyMask(const uint8_t functionModules[], uint8_t qrcode[], enum qrcodegen_Mask mask) {
+	assert(0 <= (int)mask && (int)mask <= 7);  // Disallows qrcodegen_Mask_AUTO
+	int qrsize = qrcodegen_getSize(qrcode);
+	for (int y = 0; y < qrsize; y++) {
+		for (int x = 0; x < qrsize; x++) {
+			if (getModule(functionModules, x, y))
+				continue;
+			bool invert;
+			switch ((int)mask) {
+				case 0:  invert = (x + y) % 2 == 0;                    break;
+				case 1:  invert = y % 2 == 0;                          break;
+				case 2:  invert = x % 3 == 0;                          break;
+				case 3:  invert = (x + y) % 3 == 0;                    break;
+				case 4:  invert = (x / 3 + y / 2) % 2 == 0;            break;
+				case 5:  invert = x * y % 2 + x * y % 3 == 0;          break;
+				case 6:  invert = (x * y % 2 + x * y % 3) % 2 == 0;    break;
+				case 7:  invert = ((x + y) % 2 + x * y % 3) % 2 == 0;  break;
+				default:  assert(false);  return;
+			}
+			bool val = getModule(qrcode, x, y);
+			setModule(qrcode, x, y, val ^ invert);
+		}
+	}
+}
+
+
+// Calculates and returns the penalty score based on state of the given QR Code's current modules.
+// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score.
+static long getPenaltyScore(const uint8_t qrcode[]) {
+	int qrsize = qrcodegen_getSize(qrcode);
+	long result = 0;
+
+	// Adjacent modules in row having same color, and finder-like patterns
+	for (int y = 0; y < qrsize; y++) {
+		unsigned char runHistory[7] = {0};
+		bool color = false;
+		unsigned char runX = 0;
+		for (int x = 0; x < qrsize; x++) {
+			if (getModule(qrcode, x, y) == color) {
+				runX++;
+				if (runX == 5)
+					result += PENALTY_N1;
+				else if (runX > 5)
+					result++;
+			} else {
+				addRunToHistory(runX, runHistory);
+				if (!color && hasFinderLikePattern(runHistory))
+					result += PENALTY_N3;
+				color = getModule(qrcode, x, y);
+				runX = 1;
+			}
+		}
+		addRunToHistory(runX, runHistory);
+		if (color)
+			addRunToHistory(0, runHistory);  // Dummy run of white
+		if (hasFinderLikePattern(runHistory))
+			result += PENALTY_N3;
+	}
+	// Adjacent modules in column having same color, and finder-like patterns
+	for (int x = 0; x < qrsize; x++) {
+		unsigned char runHistory[7] = {0};
+		bool color = false;
+		unsigned char runY = 0;
+		for (int y = 0; y < qrsize; y++) {
+			if (getModule(qrcode, x, y) == color) {
+				runY++;
+				if (runY == 5)
+					result += PENALTY_N1;
+				else if (runY > 5)
+					result++;
+			} else {
+				addRunToHistory(runY, runHistory);
+				if (!color && hasFinderLikePattern(runHistory))
+					result += PENALTY_N3;
+				color = getModule(qrcode, x, y);
+				runY = 1;
+			}
+		}
+		addRunToHistory(runY, runHistory);
+		if (color)
+			addRunToHistory(0, runHistory);  // Dummy run of white
+		if (hasFinderLikePattern(runHistory))
+			result += PENALTY_N3;
+	}
+
+	// 2*2 blocks of modules having same color
+	for (int y = 0; y < qrsize - 1; y++) {
+		for (int x = 0; x < qrsize - 1; x++) {
+			bool  color = getModule(qrcode, x, y);
+			if (  color == getModule(qrcode, x + 1, y) &&
+			      color == getModule(qrcode, x, y + 1) &&
+			      color == getModule(qrcode, x + 1, y + 1))
+				result += PENALTY_N2;
+		}
+	}
+
+	// Balance of black and white modules
+	int black = 0;
+	for (int y = 0; y < qrsize; y++) {
+		for (int x = 0; x < qrsize; x++) {
+			if (getModule(qrcode, x, y))
+				black++;
+		}
+	}
+	int total = qrsize * qrsize;  // Note that size is odd, so black/total != 1/2
+	// Compute the smallest integer k >= 0 such that (45-5k)% <= black/total <= (55+5k)%
+	int k = (int)((labs(black * 20L - total * 10L) + total - 1) / total) - 1;
+	result += k * PENALTY_N4;
+	return result;
+}
+
+
+// Inserts the given value to the front of the given array, which shifts over the
+// existing values and deletes the last value. A helper function for getPenaltyScore().
+static void addRunToHistory(unsigned char run, unsigned char history[7]) {
+	memmove(&history[1], &history[0], 6 * sizeof(history[0]));
+	history[0] = run;
+}
+
+
+// Tests whether the given run history has the pattern of ratio 1:1:3:1:1 in the middle, and
+// surrounded by at least 4 on either or both ends. A helper function for getPenaltyScore().
+// Must only be called immediately after a run of white modules has ended.
+static bool hasFinderLikePattern(unsigned char runHistory[7]) {
+	unsigned char n = runHistory[1];
+	// The maximum QR Code size is 177, hence the run length n <= 177.
+	// Arithmetic is promoted to int, so n*4 will not overflow.
+	return n > 0 && runHistory[2] == n && runHistory[4] == n && runHistory[5] == n
+		&& runHistory[3] == n * 3 && (runHistory[0] >= n * 4 || runHistory[6] >= n * 4);
+}
+
+
+
+/*---- Basic QR Code information ----*/
+
+// Public function - see documentation comment in header file.
+int qrcodegen_getSize(const uint8_t qrcode[]) {
+	assert(qrcode != NULL);
+	int result = qrcode[0];
+	assert((qrcodegen_VERSION_MIN * 4 + 17) <= result
+		&& result <= (qrcodegen_VERSION_MAX * 4 + 17));
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_getModule(const uint8_t qrcode[], int x, int y) {
+	assert(qrcode != NULL);
+	int qrsize = qrcode[0];
+	return (0 <= x && x < qrsize && 0 <= y && y < qrsize) && getModule(qrcode, x, y);
+}
+
+
+// Gets the module at the given coordinates, which must be in bounds.
+testable bool getModule(const uint8_t qrcode[], int x, int y) {
+	int qrsize = qrcode[0];
+	assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize);
+	int index = y * qrsize + x;
+	return getBit(qrcode[(index >> 3) + 1], index & 7);
+}
+
+
+// Sets the module at the given coordinates, which must be in bounds.
+testable void setModule(uint8_t qrcode[], int x, int y, bool isBlack) {
+	int qrsize = qrcode[0];
+	assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize);
+	int index = y * qrsize + x;
+	int bitIndex = index & 7;
+	int byteIndex = (index >> 3) + 1;
+	if (isBlack)
+		qrcode[byteIndex] |= 1 << bitIndex;
+	else
+		qrcode[byteIndex] &= (1 << bitIndex) ^ 0xFF;
+}
+
+
+// Sets the module at the given coordinates, doing nothing if out of bounds.
+testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isBlack) {
+	int qrsize = qrcode[0];
+	if (0 <= x && x < qrsize && 0 <= y && y < qrsize)
+		setModule(qrcode, x, y, isBlack);
+}
+
+
+// Returns true iff the i'th bit of x is set to 1. Requires x >= 0 and 0 <= i <= 14.
+static bool getBit(int x, int i) {
+	return ((x >> i) & 1) != 0;
+}
+
+
+
+/*---- Segment handling ----*/
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_isAlphanumeric(const char *text) {
+	assert(text != NULL);
+	for (; *text != '\0'; text++) {
+		if (strchr(ALPHANUMERIC_CHARSET, *text) == NULL)
+			return false;
+	}
+	return true;
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_isNumeric(const char *text) {
+	assert(text != NULL);
+	for (; *text != '\0'; text++) {
+		if (*text < '0' || *text > '9')
+			return false;
+	}
+	return true;
+}
+
+
+// Public function - see documentation comment in header file.
+size_t qrcodegen_calcSegmentBufferSize(enum qrcodegen_Mode mode, size_t numChars) {
+	int temp = calcSegmentBitLength(mode, numChars);
+	if (temp == -1)
+		return SIZE_MAX;
+	assert(0 <= temp && temp <= INT16_MAX);
+	return ((size_t)temp + 7) / 8;
+}
+
+
+// Returns the number of data bits needed to represent a segment
+// containing the given number of characters using the given mode. Notes:
+// - Returns -1 on failure, i.e. numChars > INT16_MAX or
+//   the number of needed bits exceeds INT16_MAX (i.e. 32767).
+// - Otherwise, all valid results are in the range [0, INT16_MAX].
+// - For byte mode, numChars measures the number of bytes, not Unicode code points.
+// - For ECI mode, numChars must be 0, and the worst-case number of bits is returned.
+//   An actual ECI segment can have shorter data. For non-ECI modes, the result is exact.
+testable int calcSegmentBitLength(enum qrcodegen_Mode mode, size_t numChars) {
+	// All calculations are designed to avoid overflow on all platforms
+	if (numChars > (unsigned int)INT16_MAX)
+		return -1;
+	long result = (long)numChars;
+	if (mode == qrcodegen_Mode_NUMERIC)
+		result = (result * 10 + 2) / 3;  // ceil(10/3 * n)
+	else if (mode == qrcodegen_Mode_ALPHANUMERIC)
+		result = (result * 11 + 1) / 2;  // ceil(11/2 * n)
+	else if (mode == qrcodegen_Mode_BYTE)
+		result *= 8;
+	else if (mode == qrcodegen_Mode_KANJI)
+		result *= 13;
+	else if (mode == qrcodegen_Mode_ECI && numChars == 0)
+		result = 3 * 8;
+	else {  // Invalid argument
+		assert(false);
+		return -1;
+	}
+	assert(result >= 0);
+	if (result > (unsigned int)INT16_MAX)
+		return -1;
+	return (int)result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeBytes(const uint8_t data[], size_t len, uint8_t buf[]) {
+	assert(data != NULL || len == 0);
+	struct qrcodegen_Segment result;
+	result.mode = qrcodegen_Mode_BYTE;
+	result.bitLength = calcSegmentBitLength(result.mode, len);
+	assert(result.bitLength != -1);
+	result.numChars = (int)len;
+	if (len > 0)
+		memcpy(buf, data, len * sizeof(buf[0]));
+	result.data = buf;
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeNumeric(const char *digits, uint8_t buf[]) {
+	assert(digits != NULL);
+	struct qrcodegen_Segment result;
+	size_t len = strlen(digits);
+	result.mode = qrcodegen_Mode_NUMERIC;
+	int bitLen = calcSegmentBitLength(result.mode, len);
+	assert(bitLen != -1);
+	result.numChars = (int)len;
+	if (bitLen > 0)
+		memset(buf, 0, ((size_t)bitLen + 7) / 8 * sizeof(buf[0]));
+	result.bitLength = 0;
+
+	unsigned int accumData = 0;
+	int accumCount = 0;
+	for (; *digits != '\0'; digits++) {
+		char c = *digits;
+		assert('0' <= c && c <= '9');
+		accumData = accumData * 10 + (unsigned int)(c - '0');
+		accumCount++;
+		if (accumCount == 3) {
+			appendBitsToBuffer(accumData, 10, buf, &result.bitLength);
+			accumData = 0;
+			accumCount = 0;
+		}
+	}
+	if (accumCount > 0)  // 1 or 2 digits remaining
+		appendBitsToBuffer(accumData, accumCount * 3 + 1, buf, &result.bitLength);
+	assert(result.bitLength == bitLen);
+	result.data = buf;
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeAlphanumeric(const char *text, uint8_t buf[]) {
+	assert(text != NULL);
+	struct qrcodegen_Segment result;
+	size_t len = strlen(text);
+	result.mode = qrcodegen_Mode_ALPHANUMERIC;
+	int bitLen = calcSegmentBitLength(result.mode, len);
+	assert(bitLen != -1);
+	result.numChars = (int)len;
+	if (bitLen > 0)
+		memset(buf, 0, ((size_t)bitLen + 7) / 8 * sizeof(buf[0]));
+	result.bitLength = 0;
+
+	unsigned int accumData = 0;
+	int accumCount = 0;
+	for (; *text != '\0'; text++) {
+		const char *temp = strchr(ALPHANUMERIC_CHARSET, *text);
+		assert(temp != NULL);
+		accumData = accumData * 45 + (unsigned int)(temp - ALPHANUMERIC_CHARSET);
+		accumCount++;
+		if (accumCount == 2) {
+			appendBitsToBuffer(accumData, 11, buf, &result.bitLength);
+			accumData = 0;
+			accumCount = 0;
+		}
+	}
+	if (accumCount > 0)  // 1 character remaining
+		appendBitsToBuffer(accumData, 6, buf, &result.bitLength);
+	assert(result.bitLength == bitLen);
+	result.data = buf;
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]) {
+	struct qrcodegen_Segment result;
+	result.mode = qrcodegen_Mode_ECI;
+	result.numChars = 0;
+	result.bitLength = 0;
+	if (assignVal < 0)
+		assert(false);
+	else if (assignVal < (1 << 7)) {
+		memset(buf, 0, 1 * sizeof(buf[0]));
+		appendBitsToBuffer(assignVal, 8, buf, &result.bitLength);
+	} else if (assignVal < (1 << 14)) {
+		memset(buf, 0, 2 * sizeof(buf[0]));
+		appendBitsToBuffer(2, 2, buf, &result.bitLength);
+		appendBitsToBuffer(assignVal, 14, buf, &result.bitLength);
+	} else if (assignVal < 1000000L) {
+		memset(buf, 0, 3 * sizeof(buf[0]));
+		appendBitsToBuffer(6, 3, buf, &result.bitLength);
+		appendBitsToBuffer(assignVal >> 10, 11, buf, &result.bitLength);
+		appendBitsToBuffer(assignVal & 0x3FF, 10, buf, &result.bitLength);
+	} else
+		assert(false);
+	result.data = buf;
+	return result;
+}
+
+
+// Calculates the number of bits needed to encode the given segments at the given version.
+// Returns a non-negative number if successful. Otherwise returns -1 if a segment has too
+// many characters to fit its length field, or the total bits exceeds INT16_MAX.
+testable int getTotalBits(const struct qrcodegen_Segment segs[], size_t len, int version) {
+	assert(segs != NULL || len == 0);
+	long result = 0;
+	for (size_t i = 0; i < len; i++) {
+		int numChars  = segs[i].numChars;
+		int bitLength = segs[i].bitLength;
+		assert(0 <= numChars  && numChars  <= INT16_MAX);
+		assert(0 <= bitLength && bitLength <= INT16_MAX);
+		int ccbits = numCharCountBits(segs[i].mode, version);
+		assert(0 <= ccbits && ccbits <= 16);
+		if (numChars >= (1L << ccbits))
+			return -1;  // The segment's length doesn't fit the field's bit width
+		result += 4L + ccbits + bitLength;
+		if (result > INT16_MAX)
+			return -1;  // The sum might overflow an int type
+	}
+	assert(0 <= result && result <= INT16_MAX);
+	return (int)result;
+}
+
+
+// Returns the bit width of the character count field for a segment in the given mode
+// in a QR Code at the given version number. The result is in the range [0, 16].
+static int numCharCountBits(enum qrcodegen_Mode mode, int version) {
+	assert(qrcodegen_VERSION_MIN <= version && version <= qrcodegen_VERSION_MAX);
+	int i = (version + 7) / 17;
+	switch (mode) {
+		case qrcodegen_Mode_NUMERIC     : { static const int temp[] = {10, 12, 14}; return temp[i]; }
+		case qrcodegen_Mode_ALPHANUMERIC: { static const int temp[] = { 9, 11, 13}; return temp[i]; }
+		case qrcodegen_Mode_BYTE        : { static const int temp[] = { 8, 16, 16}; return temp[i]; }
+		case qrcodegen_Mode_KANJI       : { static const int temp[] = { 8, 10, 12}; return temp[i]; }
+		case qrcodegen_Mode_ECI         : return 0;
+		default:  assert(false);  return -1;  // Dummy value
+	}
+}
diff --git a/src/libnma/qrcodegen.h b/src/libnma/qrcodegen.h
new file mode 100644
index 00000000..55e2bfec
--- /dev/null
+++ b/src/libnma/qrcodegen.h
@@ -0,0 +1,311 @@
+/*
+ * QR Code generator library (C)
+ *
+ * Copyright (c) Project Nayuki. (MIT License)
+ * https://www.nayuki.io/page/qr-code-generator-library
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * - The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ * - The Software is provided "as is", without warranty of any kind, express or
+ *   implied, including but not limited to the warranties of merchantability,
+ *   fitness for a particular purpose and noninfringement. In no event shall the
+ *   authors or copyright holders be liable for any claim, damages or other
+ *   liability, whether in an action of contract, tort or otherwise, arising from,
+ *   out of or in connection with the Software or the use or other dealings in the
+ *   Software.
+ */
+
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/*
+ * This library creates QR Code symbols, which is a type of two-dimension barcode.
+ * Invented by Denso Wave and described in the ISO/IEC 18004 standard.
+ * A QR Code structure is an immutable square grid of black and white cells.
+ * The library provides functions to create a QR Code from text or binary data.
+ * The library covers the QR Code Model 2 specification, supporting all versions (sizes)
+ * from 1 to 40, all 4 error correction levels, and 4 character encoding modes.
+ *
+ * Ways to create a QR Code object:
+ * - High level: Take the payload data and call qrcodegen_encodeText() or qrcodegen_encodeBinary().
+ * - Low level: Custom-make the list of segments and call
+ *   qrcodegen_encodeSegments() or qrcodegen_encodeSegmentsAdvanced().
+ * (Note that all ways require supplying the desired error correction level and various byte buffers.)
+ */
+
+
+/*---- Enum and struct types----*/
+
+/*
+ * The error correction level in a QR Code symbol.
+ */
+enum qrcodegen_Ecc {
+	// Must be declared in ascending order of error protection
+	// so that an internal qrcodegen function works properly
+	qrcodegen_Ecc_LOW = 0 ,  // The QR Code can tolerate about  7% erroneous codewords
+	qrcodegen_Ecc_MEDIUM  ,  // The QR Code can tolerate about 15% erroneous codewords
+	qrcodegen_Ecc_QUARTILE,  // The QR Code can tolerate about 25% erroneous codewords
+	qrcodegen_Ecc_HIGH    ,  // The QR Code can tolerate about 30% erroneous codewords
+};
+
+
+/*
+ * The mask pattern used in a QR Code symbol.
+ */
+enum qrcodegen_Mask {
+	// A special value to tell the QR Code encoder to
+	// automatically select an appropriate mask pattern
+	qrcodegen_Mask_AUTO = -1,
+	// The eight actual mask patterns
+	qrcodegen_Mask_0 = 0,
+	qrcodegen_Mask_1,
+	qrcodegen_Mask_2,
+	qrcodegen_Mask_3,
+	qrcodegen_Mask_4,
+	qrcodegen_Mask_5,
+	qrcodegen_Mask_6,
+	qrcodegen_Mask_7,
+};
+
+
+/*
+ * Describes how a segment's data bits are interpreted.
+ */
+enum qrcodegen_Mode {
+	qrcodegen_Mode_NUMERIC      = 0x1,
+	qrcodegen_Mode_ALPHANUMERIC = 0x2,
+	qrcodegen_Mode_BYTE         = 0x4,
+	qrcodegen_Mode_KANJI        = 0x8,
+	qrcodegen_Mode_ECI          = 0x7,
+};
+
+
+/*
+ * A segment of character/binary/control data in a QR Code symbol.
+ * The mid-level way to create a segment is to take the payload data
+ * and call a factory function such as qrcodegen_makeNumeric().
+ * The low-level way to create a segment is to custom-make the bit buffer
+ * and initialize a qrcodegen_Segment struct with appropriate values.
+ * Even in the most favorable conditions, a QR Code can only hold 7089 characters of data.
+ * Any segment longer than this is meaningless for the purpose of generating QR Codes.
+ * Moreover, the maximum allowed bit length is 32767 because
+ * the largest QR Code (version 40) has 31329 modules.
+ */
+struct qrcodegen_Segment {
+	// The mode indicator of this segment.
+	enum qrcodegen_Mode mode;
+
+	// The length of this segment's unencoded data. Measured in characters for
+	// numeric/alphanumeric/kanji mode, bytes for byte mode, and 0 for ECI mode.
+	// Always zero or positive. Not the same as the data's bit length.
+	int numChars;
+
+	// The data bits of this segment, packed in bitwise big endian.
+	// Can be null if the bit length is zero.
+	uint8_t *data;
+
+	// The number of valid data bits used in the buffer. Requires
+	// 0 <= bitLength <= 32767, and bitLength <= (capacity of data array) * 8.
+	// The character count (numChars) must agree with the mode and the bit buffer length.
+	int bitLength;
+};
+
+
+
+/*---- Macro constants and functions ----*/
+
+#define qrcodegen_VERSION_MIN   1  // The minimum version number supported in the QR Code Model 2 standard
+#define qrcodegen_VERSION_MAX  40  // The maximum version number supported in the QR Code Model 2 standard
+
+// Calculates the number of bytes needed to store any QR Code up to and including the given version number,
+// as a compile-time constant. For example, 'uint8_t buffer[qrcodegen_BUFFER_LEN_FOR_VERSION(25)];'
+// can store any single QR Code from version 1 to 25 (inclusive). The result fits in an int (or int16).
+// Requires qrcodegen_VERSION_MIN <= n <= qrcodegen_VERSION_MAX.
+#define qrcodegen_BUFFER_LEN_FOR_VERSION(n)  ((((n) * 4 + 17) * ((n) * 4 + 17) + 7) / 8 + 1)
+
+// The worst-case number of bytes needed to store one QR Code, up to and including
+// version 40. This value equals 3918, which is just under 4 kilobytes.
+// Use this more convenient value to avoid calculating tighter memory bounds for buffers.
+#define qrcodegen_BUFFER_LEN_MAX  qrcodegen_BUFFER_LEN_FOR_VERSION(qrcodegen_VERSION_MAX)
+
+
+
+/*---- Functions (high level) to generate QR Codes ----*/
+
+/*
+ * Encodes the given text string to a QR Code, returning true if encoding succeeded.
+ * If the data is too long to fit in any version in the given range
+ * at the given ECC level, then false is returned.
+ * - The input text must be encoded in UTF-8 and contain no NULs.
+ * - The variables ecl and mask must correspond to enum constant values.
+ * - Requires 1 <= minVersion <= maxVersion <= 40.
+ * - The arrays tempBuffer and qrcode must each have a length
+ *   of at least qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion).
+ * - After the function returns, tempBuffer contains no useful data.
+ * - If successful, the resulting QR Code may use numeric,
+ *   alphanumeric, or byte mode to encode the text.
+ * - In the most optimistic case, a QR Code at version 40 with low ECC
+ *   can hold any UTF-8 string up to 2953 bytes, or any alphanumeric string
+ *   up to 4296 characters, or any digit string up to 7089 characters.
+ *   These numbers represent the hard upper limit of the QR Code standard.
+ * - Please consult the QR Code specification for information on
+ *   data capacities per version, ECC level, and text encoding mode.
+ */
+bool qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode[],
+	enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl);
+
+
+/*
+ * Encodes the given binary data to a QR Code, returning true if encoding succeeded.
+ * If the data is too long to fit in any version in the given range
+ * at the given ECC level, then false is returned.
+ * - The input array range dataAndTemp[0 : dataLen] should normally be
+ *   valid UTF-8 text, but is not required by the QR Code standard.
+ * - The variables ecl and mask must correspond to enum constant values.
+ * - Requires 1 <= minVersion <= maxVersion <= 40.
+ * - The arrays dataAndTemp and qrcode must each have a length
+ *   of at least qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion).
+ * - After the function returns, the contents of dataAndTemp may have changed,
+ *   and does not represent useful data anymore.
+ * - If successful, the resulting QR Code will use byte mode to encode the data.
+ * - In the most optimistic case, a QR Code at version 40 with low ECC can hold any byte
+ *   sequence up to length 2953. This is the hard upper limit of the QR Code standard.
+ * - Please consult the QR Code specification for information on
+ *   data capacities per version, ECC level, and text encoding mode.
+ */
+bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode[],
+	enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl);
+
+
+/*---- Functions (low level) to generate QR Codes ----*/
+
+/*
+ * Renders a QR Code representing the given segments at the given error correction level.
+ * The smallest possible QR Code version is automatically chosen for the output. Returns true if
+ * QR Code creation succeeded, or false if the data is too long to fit in any version. The ECC level
+ * of the result may be higher than the ecl argument if it can be done without increasing the version.
+ * This function allows the user to create a custom sequence of segments that switches
+ * between modes (such as alphanumeric and byte) to encode text in less space.
+ * This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
+ * To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
+ * result in them being clobbered, but the QR Code output will still be correct.
+ * But the qrcode array must not overlap tempBuffer or any segment's data buffer.
+ */
+bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
+	enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]);
+
+
+/*
+ * Renders a QR Code representing the given segments with the given encoding parameters.
+ * Returns true if QR Code creation succeeded, or false if the data is too long to fit in the range of versions.
+ * The smallest possible QR Code version within the given range is automatically
+ * chosen for the output. Iff boostEcl is true, then the ECC level of the result
+ * may be higher than the ecl argument if it can be done without increasing the
+ * version. The mask number is either between 0 to 7 (inclusive) to force that
+ * mask, or -1 to automatically choose an appropriate mask (which may be slow).
+ * This function allows the user to create a custom sequence of segments that switches
+ * between modes (such as alphanumeric and byte) to encode text in less space.
+ * This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
+ * To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
+ * result in them being clobbered, but the QR Code output will still be correct.
+ * But the qrcode array must not overlap tempBuffer or any segment's data buffer.
+ */
+bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
+	int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]);
+
+
+/*
+ * Tests whether the given string can be encoded as a segment in alphanumeric mode.
+ * A string is encodable iff each character is in the following set: 0 to 9, A to Z
+ * (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
+ */
+bool qrcodegen_isAlphanumeric(const char *text);
+
+
+/*
+ * Tests whether the given string can be encoded as a segment in numeric mode.
+ * A string is encodable iff each character is in the range 0 to 9.
+ */
+bool qrcodegen_isNumeric(const char *text);
+
+
+/*
+ * Returns the number of bytes (uint8_t) needed for the data buffer of a segment
+ * containing the given number of characters using the given mode. Notes:
+ * - Returns SIZE_MAX on failure, i.e. numChars > INT16_MAX or
+ *   the number of needed bits exceeds INT16_MAX (i.e. 32767).
+ * - Otherwise, all valid results are in the range [0, ceil(INT16_MAX / 8)], i.e. at most 4096.
+ * - It is okay for the user to allocate more bytes for the buffer than needed.
+ * - For byte mode, numChars measures the number of bytes, not Unicode code points.
+ * - For ECI mode, numChars must be 0, and the worst-case number of bytes is returned.
+ *   An actual ECI segment can have shorter data. For non-ECI modes, the result is exact.
+ */
+size_t qrcodegen_calcSegmentBufferSize(enum qrcodegen_Mode mode, size_t numChars);
+
+
+/*
+ * Returns a segment representing the given binary data encoded in
+ * byte mode. All input byte arrays are acceptable. Any text string
+ * can be converted to UTF-8 bytes and encoded as a byte mode segment.
+ */
+struct qrcodegen_Segment qrcodegen_makeBytes(const uint8_t data[], size_t len, uint8_t buf[]);
+
+
+/*
+ * Returns a segment representing the given string of decimal digits encoded in numeric mode.
+ */
+struct qrcodegen_Segment qrcodegen_makeNumeric(const char *digits, uint8_t buf[]);
+
+
+/*
+ * Returns a segment representing the given text string encoded in alphanumeric mode.
+ * The characters allowed are: 0 to 9, A to Z (uppercase only), space,
+ * dollar, percent, asterisk, plus, hyphen, period, slash, colon.
+ */
+struct qrcodegen_Segment qrcodegen_makeAlphanumeric(const char *text, uint8_t buf[]);
+
+
+/*
+ * Returns a segment representing an Extended Channel Interpretation
+ * (ECI) designator with the given assignment value.
+ */
+struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]);
+
+
+/*---- Functions to extract raw data from QR Codes ----*/
+
+/*
+ * Returns the side length of the given QR Code, assuming that encoding succeeded.
+ * The result is in the range [21, 177]. Note that the length of the array buffer
+ * is related to the side length - every 'uint8_t qrcode[]' must have length at least
+ * qrcodegen_BUFFER_LEN_FOR_VERSION(version), which equals ceil(size^2 / 8 + 1).
+ */
+int qrcodegen_getSize(const uint8_t qrcode[]);
+
+
+/*
+ * Returns the color of the module (pixel) at the given coordinates, which is false
+ * for white or true for black. The top left corner has the coordinates (x=0, y=0).
+ * If the given coordinates are out of bounds, then false (white) is returned.
+ */
+bool qrcodegen_getModule(const uint8_t qrcode[], int x, int y);
+
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/libnma/tests/bar-code.c b/src/libnma/tests/bar-code.c
new file mode 100644
index 00000000..c27ee314
--- /dev/null
+++ b/src/libnma/tests/bar-code.c
@@ -0,0 +1,177 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public License as
+ * published by the ree Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright 2018, 2019 Red Hat, Inc.
+ */
+
+#include "nm-default.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include <gtk/gtk.h>
+
+#include "nma-bar-code-widget.h"
+
+static gboolean
+delete (GtkWidget *widget, GdkEvent *event, gpointer user_data)
+{
+        gtk_main_quit ();
+
+        return FALSE;
+}
+
+static void
+ssid_changed (GtkEditable *editable, gpointer user_data)
+{
+	NMConnection *connection = NM_CONNECTION (user_data);
+	NMSettingWireless *s_wireless = nm_connection_get_setting_wireless (connection);
+	gs_unref_bytes GBytes *ssid = NULL;
+	GtkEntryBuffer *buffer;
+
+	g_return_if_fail (s_wireless);
+
+	buffer = gtk_entry_get_buffer (GTK_ENTRY (editable));
+	ssid = g_bytes_new_static (gtk_entry_buffer_get_text (buffer),
+	                           gtk_entry_buffer_get_bytes (buffer));
+
+	g_object_set (s_wireless,
+	              NM_SETTING_WIRELESS_SSID, ssid,
+	              NULL);
+}
+
+static void
+password_changed (GtkEditable *editable, gpointer user_data)
+{
+	NMConnection *connection = NM_CONNECTION (user_data);
+	NMSettingWirelessSecurity *s_wsec = nm_connection_get_setting_wireless_security (connection);
+
+	if (!s_wsec)
+		return;
+
+	g_object_set (s_wsec,
+	              NM_SETTING_WIRELESS_SECURITY_PSK,
+	              gtk_entry_get_text (GTK_ENTRY (editable)),
+	              NULL);
+}
+
+static void
+key_mgmt_changed (GtkComboBox *combo_box, gpointer user_data)
+{
+	NMConnection *connection = NM_CONNECTION (user_data);
+	const char *key_mgmt = gtk_combo_box_get_active_id (combo_box);
+	NMSettingWirelessSecurity *s_wsec = nm_connection_get_setting_wireless_security (connection);
+	GtkWidget *pass = g_object_get_data (G_OBJECT (combo_box), "pass");
+
+	if (!key_mgmt) {
+		nm_connection_remove_setting (connection, NM_TYPE_SETTING_WIRELESS_SECURITY);
+		gtk_widget_set_sensitive (pass, FALSE);
+		return;
+	}
+
+	if (!s_wsec) {
+		s_wsec = NM_SETTING_WIRELESS_SECURITY (nm_setting_wireless_security_new ());
+		nm_connection_add_setting (connection, NM_SETTING (s_wsec));
+		gtk_widget_set_sensitive (pass, TRUE);
+		password_changed (GTK_EDITABLE (pass), connection);
+	}
+
+	g_object_set (s_wsec,
+	              NM_SETTING_WIRELESS_SECURITY_KEY_MGMT, key_mgmt,
+	              NULL);
+}
+
+int
+main (int argc, char *argv[])
+{
+	GtkWidget *w, *pass;
+	GtkWidget *grid;
+	NMConnection *connection = NULL;
+	gs_unref_bytes GBytes *ssid = g_bytes_new_static ("\"ab:cd\"", 13);
+
+	connection = nm_simple_connection_new ();
+	nm_connection_add_setting (connection,
+		g_object_new (NM_TYPE_SETTING_CONNECTION,
+		              NM_SETTING_CONNECTION_ID, "fifik",
+		              NULL));
+	nm_connection_add_setting (connection,
+	                           nm_setting_wireless_new ());
+
+        gtk_init (&argc, &argv);
+
+        w = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+        gtk_widget_show (w);
+	gtk_window_set_default_size (GTK_WINDOW (w), 800, 680);
+	g_signal_connect (w, "delete-event", G_CALLBACK (delete), NULL);
+
+	grid = gtk_grid_new ();
+	gtk_widget_show (grid);
+	gtk_grid_set_column_spacing (GTK_GRID (grid), 6);
+	gtk_grid_set_row_spacing (GTK_GRID (grid), 6);
+	g_object_set (grid,
+	              "margin_start", 6,
+	              "margin_end", 6,
+	              "margin_top", 6,
+	              "margin_bottom", 6,
+	              NULL);
+	gtk_container_add (GTK_CONTAINER (w), grid);
+
+	w = gtk_label_new ("SSID");
+	gtk_widget_show (w);
+	g_object_set (w, "xalign", 1.0, NULL);
+	gtk_grid_attach (GTK_GRID (grid), w, 0, 0, 1, 1);
+
+	w = gtk_entry_new ();
+	g_signal_connect (w, "changed", G_CALLBACK (ssid_changed), connection);
+	gtk_entry_set_text (GTK_ENTRY (w), "\"ab:cd\"");
+	gtk_widget_show (w);
+	gtk_grid_attach (GTK_GRID (grid), w, 1, 0, 1, 1);
+
+	w = gtk_label_new ("Password");
+	gtk_widget_show (w);
+	g_object_set (w, "xalign", 1.0, NULL);
+	gtk_grid_attach (GTK_GRID (grid), w, 0, 1, 1, 1);
+
+	pass = gtk_entry_new ();
+	g_signal_connect (pass, "changed", G_CALLBACK (password_changed), connection);
+	gtk_entry_set_text (GTK_ENTRY (pass), "lolofon");
+	gtk_widget_show (pass);
+	gtk_grid_attach (GTK_GRID (grid), pass, 1, 1, 1, 1);
+
+	w = gtk_label_new ("Key Management");
+	gtk_widget_show (w);
+	g_object_set (w, "xalign", 1.0, NULL);
+	gtk_grid_attach (GTK_GRID (grid), w, 0, 2, 1, 1);
+
+	w = gtk_combo_box_text_new ();
+	gtk_combo_box_text_append (GTK_COMBO_BOX_TEXT (w), NULL, "No Password");
+	gtk_combo_box_text_append (GTK_COMBO_BOX_TEXT (w), "none", "WEP: none");
+	gtk_combo_box_text_append (GTK_COMBO_BOX_TEXT (w), "ieee8021x", "WEP: ieee8021x");
+	gtk_combo_box_text_append (GTK_COMBO_BOX_TEXT (w), "wpa-none", "WPA: wpa-none");
+	gtk_combo_box_text_append (GTK_COMBO_BOX_TEXT (w), "wpa-psk", "WPA: wpa-psk");
+	g_object_set_data (G_OBJECT (w), "pass", pass);
+	g_signal_connect (w, "changed", G_CALLBACK (key_mgmt_changed), connection);
+	gtk_combo_box_set_active_id (GTK_COMBO_BOX (w), "wpa-psk");
+	gtk_widget_show (w);
+	gtk_grid_attach (GTK_GRID (grid), w, 1, 2, 1, 1);
+
+	w = nma_bar_code_widget_new (connection);
+	gtk_widget_show (w);
+	gtk_widget_set_vexpand (w, TRUE);
+	gtk_widget_set_hexpand (w, TRUE);
+	gtk_grid_attach (GTK_GRID (grid), w, 0, 3, 2, 1);
+
+	gtk_main ();
+}