clients: Add demo application for tablets

Note that this application does not follow best practices for handling tablet
events. The events are grouped by frame, all processing should be done in the
frame instead of the respective handler.

A good toolkit would accumulate the data in the events and provide them as one
event to the actual client once the frame is received. toytoolkit just hooks
up the handler one-by-one, so we're doing this here as well.

Co-authored-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Lyude Paul <thatslyude@gmail.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Bastian Farkas <bfarkas@de.adit-jv.com>
Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>

2 files changed, 261 insertions, 0 deletions

diff --git a/clients/meson.build b/clients/meson.build
index 539e9db2..2fe10956 100644
--- a/clients/meson.build
+++ b/clients/meson.build
@@ -330,6 +330,13 @@ demo_clients = [
 		'basename': 'subsurfaces',
 		'deps': [ 'egl', 'glesv2', 'wayland-egl' ]
 	},
+	{
+		'basename': 'tablet',
+		'add_sources': [
+			tablet_unstable_v2_client_protocol_h,
+			tablet_unstable_v2_protocol_c,
+		],
+	},
 	{ 'basename': 'transformed' },
 ]
 
diff --git a/clients/tablet.c b/clients/tablet.c
new file mode 100644
index 00000000..112fc4b5
--- /dev/null
+++ b/clients/tablet.c
@@ -0,0 +1,254 @@
+/*
+ * Copyright © 2014 Lyude
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and
+ * its documentation for any purpose is hereby granted without fee, provided
+ * that the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of the copyright holders not be used in
+ * advertising or publicity pertaining to distribution of the software
+ * without specific, written prior permission.  The copyright holders make
+ * no representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
+ * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE
+ */
+#include "config.h"
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <cairo.h>
+#include <math.h>
+#include <assert.h>
+#include <stdbool.h>
+
+#include <linux/input.h>
+#include <wayland-client.h>
+
+#include "window.h"
+#include "tablet-unstable-v2-client-protocol.h"
+
+struct display *display;
+struct window *window;
+struct widget *widget;
+
+cairo_surface_t *draw_buffer;
+
+int old_x, old_y;
+int current_x, current_y;
+enum zwp_tablet_tool_v2_type tool_type;
+
+bool tablet_is_down;
+
+double current_pressure;
+
+#define WL_TABLET_AXIS_MAX 65535
+
+static void
+redraw_handler(struct widget *widget, void *data)
+{
+	cairo_surface_t *surface;
+	cairo_t *window_cr, *drawing_cr;
+	struct rectangle allocation;
+
+	widget_get_allocation(widget, &allocation);
+
+	surface = window_get_surface(window);
+
+	/* Setup the background */
+	window_cr = cairo_create(surface);
+	cairo_set_operator(window_cr, CAIRO_OPERATOR_SOURCE);
+	cairo_rectangle(window_cr,
+			allocation.x,
+			allocation.y,
+			allocation.width,
+			allocation.height);
+	cairo_set_source_rgba(window_cr, 0, 0, 0, 0.8);
+	cairo_fill(window_cr);
+
+	/* Update the drawing buffer */
+	if (tablet_is_down) {
+		if (old_x != -1 && old_y != -1) {
+			drawing_cr = cairo_create(draw_buffer);
+			if (tool_type == ZWP_TABLET_TOOL_V2_TYPE_PEN) {
+				cairo_set_source_rgb(drawing_cr, 1, 1, 1);
+				cairo_set_line_width(drawing_cr,
+						     current_pressure /
+						     WL_TABLET_AXIS_MAX * 7 + 1);
+			} else if (tool_type == ZWP_TABLET_TOOL_V2_TYPE_ERASER) {
+				cairo_set_operator(drawing_cr, CAIRO_OPERATOR_CLEAR);
+				cairo_set_source_rgb(drawing_cr, 0, 0, 0);
+				cairo_set_line_width(drawing_cr,
+						     current_pressure /
+						     WL_TABLET_AXIS_MAX * 30 + 10);
+			}
+
+			cairo_set_line_cap(drawing_cr, CAIRO_LINE_CAP_ROUND);
+
+			cairo_translate(drawing_cr,
+					-allocation.x,
+					-allocation.y);
+			cairo_move_to(drawing_cr, old_x, old_y);
+			cairo_line_to(drawing_cr, current_x, current_y);
+			cairo_stroke(drawing_cr);
+
+			cairo_destroy(drawing_cr);
+		}
+
+		old_x = current_x;
+		old_y = current_y;
+	}
+
+	/* Squash the drawing buffer onto the window's buffer */
+	cairo_set_source_surface(window_cr,
+				 draw_buffer,
+				 allocation.x,
+				 allocation.y);
+	cairo_set_operator(window_cr, CAIRO_OPERATOR_ADD);
+	cairo_rectangle(window_cr,
+			allocation.x,
+			allocation.y,
+			allocation.width,
+			allocation.height);
+	cairo_clip(window_cr);
+	cairo_paint(window_cr);
+
+	cairo_destroy(window_cr);
+
+	cairo_surface_destroy(surface);
+}
+
+static void
+resize_handler(struct widget *widget,
+	       int32_t width, int32_t height,
+	       void *data)
+{
+	cairo_surface_t *tmp_buffer;
+	cairo_t *cr;
+
+	tmp_buffer = draw_buffer;
+	draw_buffer = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
+						 width, height);
+	cr = cairo_create(draw_buffer);
+	cairo_set_source_rgba(cr, 0, 0, 0, 0);
+	cairo_rectangle(cr, 0, 0, width, height);
+	cairo_fill(cr);
+
+	if (tmp_buffer) {
+		cairo_set_source_surface(cr, tmp_buffer, 0, 0);
+		cairo_rectangle(cr, 0, 0, width, height);
+		cairo_clip(cr);
+		cairo_paint(cr);
+	}
+
+	cairo_destroy(cr);
+
+	cairo_surface_destroy(tmp_buffer);
+}
+
+static void
+proximity_in_handler(struct widget *widget, struct tablet_tool *tool,
+		     struct tablet *tablet, void *data)
+{
+	tool_type = tablet_tool_get_type(tool);
+}
+
+static void
+pressure_handler(struct widget *widget, struct tablet_tool *tool,
+		 uint32_t pressure, void *data)
+{
+	current_pressure = pressure;
+}
+
+static int
+tablet_motion_handler(struct widget *widget, struct tablet_tool *tool,
+		      float x, float y, void *data)
+{
+	int cursor;
+
+	current_x = x;
+	current_y = y;
+
+	if (tablet_is_down) {
+		widget_schedule_redraw(widget);
+		cursor = CURSOR_HAND1;
+	} else {
+		cursor = CURSOR_LEFT_PTR;
+	}
+
+	return cursor;
+}
+
+static void
+tablet_down_handler(struct widget *widget, struct tablet_tool *tool, void *data)
+{
+	tablet_is_down = true;
+}
+
+static void
+tablet_up_handler(struct widget *widget, struct tablet_tool *tool, void *data)
+{
+	tablet_is_down = false;
+	old_x = -1;
+	old_y = -1;
+}
+
+static void
+init_globals(void)
+{
+	window = window_create(display);
+	widget = window_frame_create(window, NULL);
+	window_set_title(window, "Wayland Tablet Demo");
+	old_x = -1;
+	old_y = -1;
+
+	widget_set_tablet_tool_axis_handlers(widget,
+					     tablet_motion_handler,
+					     pressure_handler,
+					     NULL, NULL,
+					     NULL, NULL, NULL);
+	widget_set_tablet_tool_down_handler(widget, tablet_down_handler);
+	widget_set_tablet_tool_up_handler(widget, tablet_up_handler);
+	widget_set_tablet_tool_proximity_handlers(widget,
+						  proximity_in_handler,
+						  NULL);
+	widget_set_redraw_handler(widget, redraw_handler);
+	widget_set_resize_handler(widget, resize_handler);
+
+	widget_schedule_resize(widget, 1000, 800);
+}
+
+static void
+cleanup(void)
+{
+	widget_destroy(widget);
+	window_destroy(window);
+}
+
+int
+main(int argc, char *argv[])
+{
+	display = display_create(&argc, argv);
+	if (display == NULL) {
+		fprintf(stderr, "failed to create display: %m\n");
+		return -1;
+	}
+
+	init_globals();
+
+	display_run(display);
+
+	cleanup();
+
+	display_destroy(display);
+
+	return 0;
+}