/* Draw a rectangle on the screen */
static void
draw_brush (GtkWidget *widget,
gdouble x,
gdouble y)
{
GdkRectangle update_rect;
cairo_t *cr;
if (surface == NULL ||
cairo_image_surface_get_width (surface) != gtk_widget_get_width (widget) ||
cairo_image_surface_get_height (surface) != gtk_widget_get_height (widget))
create_surface (widget);
update_rect.x = x - 3;
update_rect.y = y - 3;
update_rect.width = 6;
update_rect.height = 6;
/* Paint to the surface, where we store our state */
cr = cairo_create (surface);
gdk_cairo_rectangle (cr, &update_rect);
cairo_fill (cr);
cairo_destroy (cr);
gtk_widget_queue_draw (widget);
}
static void
cb_compose_images_snapshot (GtkWidget *widget,
GtkSnapshot *snapshot)
{
const int width = gtk_widget_get_width (widget);
const int height = gtk_widget_get_height (widget);
/* This is only relevant when an image gets transitioned to being deleted,
* but we just always push a clip node here, for simplicity. */
gtk_snapshot_push_clip (snapshot,
&GRAPHENE_RECT_INIT (0, 0, width, height),
"ComposeImagesClip");
GTK_WIDGET_CLASS (cb_compose_images_parent_class)->snapshot (widget, snapshot);
gtk_snapshot_pop (snapshot);
}
/* Create a new surface of the appropriate size to store our scribbles */
static void
create_surface (GtkWidget *widget)
{
cairo_t *cr;
if (surface)
cairo_surface_destroy (surface);
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
gtk_widget_get_width (widget),
gtk_widget_get_height (widget));
/* Initialize the surface to white */
cr = cairo_create (surface);
cairo_set_source_rgb (cr, 1, 1, 1);
cairo_paint (cr);
cairo_destroy (cr);
}