--- /dev/null
+/* Paint
+ *
+ * Demonstrates practical handling of drawing tablets in a real world
+ * usecase.
+ */
+#include <gtk/gtk.h>
+
+typedef struct
+{
+ GtkEventBox parent_instance;
+ cairo_surface_t *surface;
+ cairo_t *cr;
+ GdkRGBA draw_color;
+
+ GtkGesture *stylus_gesture;
+} DrawingArea;
+
+typedef struct
+{
+ GtkEventBoxClass parent_class;
+} DrawingAreaClass;
+
+G_DEFINE_TYPE (DrawingArea, drawing_area, GTK_TYPE_EVENT_BOX)
+
+static void
+drawing_area_ensure_surface (DrawingArea *area,
+ gint width,
+ gint height)
+{
+ if (!area->surface ||
+ cairo_image_surface_get_width (area->surface) != width ||
+ cairo_image_surface_get_height (area->surface) != height)
+ {
+ cairo_surface_t *surface;
+
+ surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+ width, height);
+ if (area->surface)
+ {
+ cairo_t *cr;
+
+ cr = cairo_create (surface);
+ cairo_set_source_surface (cr, area->surface, 0, 0);
+ cairo_paint (cr);
+
+ cairo_surface_destroy (area->surface);
+ cairo_destroy (area->cr);
+ cairo_destroy (cr);
+ }
+
+ area->surface = surface;
+ area->cr = cairo_create (surface);
+ }
+}
+
+static void
+drawing_area_size_allocate (GtkWidget *widget,
+ GtkAllocation *allocation)
+{
+ DrawingArea *area = (DrawingArea *) widget;
+
+ drawing_area_ensure_surface (area, allocation->width, allocation->height);
+
+ GTK_WIDGET_CLASS (drawing_area_parent_class)->size_allocate (widget, allocation);
+}
+
+static void
+drawing_area_map (GtkWidget *widget)
+{
+ GtkAllocation allocation;
+
+ GTK_WIDGET_CLASS (drawing_area_parent_class)->map (widget);
+
+ gdk_window_set_event_compression (gtk_widget_get_window (widget), TRUE);
+
+ gtk_widget_get_allocation (widget, &allocation);
+ drawing_area_ensure_surface ((DrawingArea *) widget,
+ allocation.width, allocation.height);
+}
+
+static void
+drawing_area_unmap (GtkWidget *widget)
+{
+ DrawingArea *area = (DrawingArea *) widget;
+
+ g_clear_pointer (&area->cr, cairo_destroy);
+ g_clear_pointer (&area->surface, cairo_surface_destroy);
+
+ GTK_WIDGET_CLASS (drawing_area_parent_class)->unmap (widget);
+}
+
+static gboolean
+drawing_area_draw (GtkWidget *widget,
+ cairo_t *cr)
+{
+ DrawingArea *area = (DrawingArea *) widget;
+ GtkAllocation allocation;
+
+ gtk_widget_get_allocation (widget, &allocation);
+
+ cairo_set_source_rgb (cr, 1, 1, 1);
+ cairo_paint (cr);
+
+ cairo_set_source_surface (cr, area->surface, 0, 0);
+ cairo_paint (cr);
+
+ cairo_set_source_rgb (cr, 0.6, 0.6, 0.6);
+ cairo_rectangle (cr, 0, 0, allocation.width, allocation.height);
+ cairo_stroke (cr);
+
+ return TRUE;
+}
+
+static void
+drawing_area_class_init (DrawingAreaClass *klass)
+{
+ GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+
+ widget_class->size_allocate = drawing_area_size_allocate;
+ widget_class->draw = drawing_area_draw;
+ widget_class->map = drawing_area_map;
+ widget_class->unmap = drawing_area_unmap;
+}
+
+static void
+drawing_area_apply_stroke (DrawingArea *area,
+ GdkDeviceTool *tool,
+ gdouble x,
+ gdouble y,
+ gdouble pressure)
+{
+ if (gdk_device_tool_get_tool_type (tool) == GDK_DEVICE_TOOL_TYPE_ERASER)
+ {
+ cairo_set_line_width (area->cr, 10 * pressure);
+ cairo_set_operator (area->cr, CAIRO_OPERATOR_DEST_OUT);
+ }
+ else
+ {
+ cairo_set_line_width (area->cr, 4 * pressure);
+ cairo_set_operator (area->cr, CAIRO_OPERATOR_SATURATE);
+ }
+
+ cairo_set_source_rgba (area->cr, area->draw_color.red,
+ area->draw_color.green, area->draw_color.blue,
+ area->draw_color.alpha * pressure);
+
+ //cairo_set_source_rgba (area->cr, 0, 0, 0, pressure);
+
+ cairo_line_to (area->cr, x, y);
+ cairo_stroke (area->cr);
+ cairo_move_to (area->cr, x, y);
+}
+
+static void
+stylus_gesture_down (GtkGestureStylus *gesture,
+ gdouble x,
+ gdouble y,
+ DrawingArea *area)
+{
+ cairo_new_path (area->cr);
+}
+
+static void
+stylus_gesture_motion (GtkGestureStylus *gesture,
+ gdouble x,
+ gdouble y,
+ DrawingArea *area)
+{
+ GdkDeviceTool *tool;
+ gdouble pressure;
+
+ tool = gtk_gesture_stylus_get_device_tool (gesture);
+
+ if (!gtk_gesture_stylus_get_axis (gesture, GDK_AXIS_PRESSURE, &pressure))
+ pressure = 1;
+
+ drawing_area_apply_stroke (area, tool, x, y, pressure);
+ gtk_widget_queue_draw (GTK_WIDGET (area));
+}
+
+static void
+drawing_area_init (DrawingArea *area)
+{
+ gtk_event_box_set_visible_window (GTK_EVENT_BOX (area), TRUE);
+
+ area->stylus_gesture = gtk_gesture_stylus_new (GTK_WIDGET (area));
+ g_signal_connect (area->stylus_gesture, "down",
+ G_CALLBACK (stylus_gesture_down), area);
+ g_signal_connect (area->stylus_gesture, "motion",
+ G_CALLBACK (stylus_gesture_motion), area);
+
+ area->draw_color = (GdkRGBA) { 0, 0, 0, 1 };
+}
+
+GtkWidget *
+drawing_area_new (void)
+{
+ return g_object_new (drawing_area_get_type (), NULL);
+}
+
+void
+drawing_area_set_color (DrawingArea *area,
+ GdkRGBA *color)
+{
+ area->draw_color = *color;
+}
+
+static void
+color_button_color_set (GtkColorButton *button,
+ DrawingArea *draw_area)
+{
+ GdkRGBA color;
+
+ gtk_color_chooser_get_rgba (GTK_COLOR_CHOOSER (button), &color);
+ drawing_area_set_color (draw_area, &color);
+}
+
+GtkWidget *
+do_paint (GtkWidget *toplevel)
+{
+ static GtkWidget *window = NULL;
+
+ if (!window)
+ {
+ GtkWidget *draw_area, *headerbar, *colorbutton;
+
+ window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+
+ draw_area = drawing_area_new ();
+ gtk_container_add (GTK_CONTAINER (window), draw_area);
+
+ headerbar = gtk_header_bar_new ();
+ gtk_header_bar_set_title (GTK_HEADER_BAR (headerbar), "Paint");
+ gtk_header_bar_set_show_close_button (GTK_HEADER_BAR (headerbar), TRUE);
+
+ colorbutton = gtk_color_button_new ();
+ g_signal_connect (colorbutton, "color-set",
+ G_CALLBACK (color_button_color_set), draw_area);
+ gtk_color_chooser_set_rgba (GTK_COLOR_CHOOSER (colorbutton),
+ &(GdkRGBA) { 0, 0, 0, 1 });
+
+ gtk_header_bar_pack_end (GTK_HEADER_BAR (headerbar), colorbutton);
+ gtk_window_set_titlebar (GTK_WINDOW (window), headerbar);
+
+ g_signal_connect (window, "destroy",
+ G_CALLBACK (gtk_widget_destroyed), &window);
+ }
+
+ if (!gtk_widget_get_visible (window))
+ gtk_widget_show_all (window);
+ else
+ gtk_widget_destroy (window);
+
+ return window;
+}
projects / gtk+3.0.git / commitdiff