Use pngquant to make the application icons take up less space

Fixes https://github.com/hughsie/appstream-glib/issues/203

4 files changed, 42 insertions, 0 deletions

diff --git a/contrib/libappstream-glib.spec.in b/contrib/libappstream-glib.spec.in
index ccfb006..419a38a 100644
--- a/contrib/libappstream-glib.spec.in
+++ b/contrib/libappstream-glib.spec.in
@@ -69,6 +69,7 @@ GLib headers and libraries for appstream-glib.
 %package builder
 Summary: Library and command line tools for building AppStream metadata
 Requires: %{name}%{?_isa} = %{version}-%{release}
+Requires: pngquant
 
 %description builder
 This library and command line tool is used for building AppStream metadata
diff --git a/libappstream-builder/asb-app.c b/libappstream-builder/asb-app.c
index fa42160..b44f091 100644
--- a/libappstream-builder/asb-app.c
+++ b/libappstream-builder/asb-app.c
@@ -33,6 +33,7 @@
 #include <appstream-glib.h>
 
 #include "asb-app.h"
+#include "asb-utils.h"
 
 typedef struct
 {
@@ -188,6 +189,10 @@ asb_app_save_resources (AsbApp *app, AsbAppSaveFlags save_flags, GError **error)
 		if (!gdk_pixbuf_save (pixbuf, filename, "png", error, NULL))
 			return FALSE;
 
+		/* optimize the icon */
+		if (!asb_utils_optimize_png (filename, error))
+			return FALSE;
+
 		/* set new AppStream compatible icon name */
 		asb_package_log (priv->pkg,
 				 ASB_PACKAGE_LOG_LEVEL_DEBUG,
diff --git a/libappstream-builder/asb-utils.c b/libappstream-builder/asb-utils.c
index f1b48e9..503c379 100644
--- a/libappstream-builder/asb-utils.c
+++ b/libappstream-builder/asb-utils.c
@@ -281,6 +281,40 @@ asb_utils_explode_file (struct archive_entry *entry, const gchar *dir)
 }
 
 /**
+ * asb_utils_optimize_png:
+ * @filename: package filename
+ * @error: A #GError or %NULL
+ *
+ * Optimises a PNG if pngquant is installed on the system.
+ *
+ * Returns: %TRUE for success, %FALSE otherwise
+ **/
+gboolean
+asb_utils_optimize_png (const gchar *filename, GError **error)
+{
+	g_autofree gchar *standard_error = NULL;
+	gint exit_status = 0;
+	const gchar *argv[] = { "/usr/bin/pngquant", "--skip-if-larger",
+				"--strip", "--ext", ".png",
+				"--force", "--speed", "1", filename, NULL };
+	if (!g_file_test (argv[0], G_FILE_TEST_IS_EXECUTABLE))
+		return TRUE;
+	if (!g_spawn_sync (NULL, (gchar **) argv, NULL, G_SPAWN_DEFAULT,
+			   NULL, NULL, NULL, &standard_error, &exit_status, error))
+		return FALSE;
+	if (exit_status != 0) {
+		g_autofree gchar *argv_str = g_strjoinv (" ", (gchar **) argv);
+		g_set_error (error,
+			     AS_APP_ERROR,
+			     AS_APP_ERROR_FAILED,
+			     "failed to run %s: %s",
+			     argv_str, standard_error);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+/**
  * asb_utils_explode:
  * @filename: package filename
  * @dir: directory to decompress into
diff --git a/libappstream-builder/asb-utils.h b/libappstream-builder/asb-utils.h
index 266f311..31922b6 100644
--- a/libappstream-builder/asb-utils.h
+++ b/libappstream-builder/asb-utils.h
@@ -42,6 +42,8 @@ gboolean	 asb_utils_explode			(const gchar	*filename,
 							 const gchar	*dir,
 							 GPtrArray	*glob,
 							 GError		**error);
+gboolean	 asb_utils_optimize_png			(const gchar	*filename,
+							 GError		**error);
 gchar		*asb_utils_get_cache_id_for_filename	(const gchar	*filename);
 
 gchar		*asb_utils_get_builder_id		(void);