gtk_fb: WIP switch to using GtkDrawingArea

I still need to dig into which is preferable from a performance
perspective, but the existing GtkImage integration with setting
its cairo surface for the page flip seems to cause lots of
size-allocations and errors on wayland as-is.

Note this also bumps the rototiller submodule to a different branch
for til_fb_context().

3 files changed, 26 insertions, 14 deletions

diff --git a/.gitmodules b/.gitmodules
index 904b734..6ce2cdd 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,4 @@
 [submodule "rototiller"]
 	path = rototiller
 	url = https://git.pengaru.com/rototiller
+	branch = fbcontext
diff --git a/rototiller b/rototiller
-Subproject 4351afc62b3dd1c7fb7f0bc563dae22ee0ec73d
+Subproject 2c01f07385db88fa92f3a3789457c68db0d7d49
diff --git a/src/gtk_fb.c b/src/gtk_fb.c
index f9fd015..3faad8f 100644
--- a/src/gtk_fb.c
+++ b/src/gtk_fb.c
@@ -26,7 +26,8 @@
 
 typedef struct gtk_fb_t {
 	GtkWidget	*window;
-	GtkWidget	*image;
+	GtkWidget	*area;
+	cairo_t		*cairo;
 	unsigned	width, height;
 	unsigned	fullscreen:1;
 	unsigned	resized:1;
@@ -39,13 +40,13 @@ struct gtk_fb_page_t {
 };
 
 
-/* called on "size-allocate" for the fb's gtk image */
+/* called on "size-allocate" for the fb's gtk area */
 static void resized(GtkWidget *widget, GtkAllocation *allocation, gpointer user_data)
 {
 	gtk_fb_t	*c = user_data;
 	GtkAllocation	alloc;
 
-	gtk_widget_get_allocation(c->image, &alloc);
+	gtk_widget_get_allocation(c->area, &alloc);
 	if (c->width != alloc.width ||
 	    c->height != alloc.height) {
 
@@ -133,18 +134,24 @@ static void gtk_fb_shutdown(til_fb_t *fb, void *context)
 static gboolean draw_cb(GtkWidget *widget, cairo_t *cr, gpointer user_data)
 {
 	til_fb_t	*fb = user_data;
+	gtk_fb_t	*c = til_fb_context(fb);
+
+	/* this is icky but we need to pass the cr to gtk_fb_page_flip(), til_fb_t is
+	 * the convenient via.
+	 */
+	c->cairo = cr;
 
 	til_fb_flip(fb);
 
 	return FALSE;
 }
 
-/* this just queues drawing the image on the "tick" */
+/* this just queues drawing the area on the "tick" */
 static gboolean queue_draw_cb(GtkWidget *widget, GdkFrameClock *frame_clock, gpointer user_data)
 {
 	gtk_fb_t	*c = user_data;
 
-	gtk_widget_queue_draw(c->image);
+	gtk_widget_queue_draw(c->area);
 
 	return G_SOURCE_CONTINUE;
 }
@@ -158,12 +165,13 @@ static int gtk_fb_acquire(til_fb_t *fb, void *context, void *page)
 	if (!c->window)
 		return -EPIPE;
 
-	c->image = gtk_image_new_from_surface(p->surface);
-	g_signal_connect_after(c->image, "size-allocate", G_CALLBACK(resized), c);
-	g_signal_connect(c->image, "draw", G_CALLBACK(draw_cb), fb);
-	gtk_widget_set_size_request(c->image, c->width, c->height);
-	gtk_widget_add_tick_callback(c->image, queue_draw_cb, c, NULL);
-	gtk_container_add(GTK_CONTAINER(c->window), c->image);
+	c->area = gtk_drawing_area_new();
+	/* XXX: copy from p->surface to c->area */
+	gtk_widget_set_size_request(c->area, c->width, c->height);
+	g_signal_connect_after(c->area, "size-allocate", G_CALLBACK(resized), c);
+	g_signal_connect(c->area, "draw", G_CALLBACK(draw_cb), fb);
+	gtk_widget_add_tick_callback(c->area, queue_draw_cb, c, NULL);
+	gtk_container_add(GTK_CONTAINER(c->window), c->area);
 	gtk_widget_show_all(c->window);
 
 	return 0;
@@ -175,7 +183,7 @@ static void gtk_fb_release(til_fb_t *fb, void *context)
 	gtk_fb_t	*c = context;
 
 	if (c->window)
-		gtk_widget_destroy(c->image);
+		gtk_widget_destroy(c->area);
 }
 
 
@@ -227,7 +235,7 @@ static int gtk_fb_page_free(til_fb_t *fb, void *context, void *page)
 
 /* XXX: due to gtk's event-driven nature, this isn't a vsync-synchronous page flip,
  * so til_fb_flip() must be scheduled independently to not just spin.
- * The "draw" signal on the image is used to drive til_fb_flip() on frameclock "ticks",
+ * The "draw" signal on the area is used to drive til_fb_flip() on frameclock "ticks",
  * a method suggested by Christian Hergert, thanks!
  */
 static int gtk_fb_page_flip(til_fb_t *fb, void *context, void *page)
@@ -239,7 +247,10 @@ static int gtk_fb_page_flip(til_fb_t *fb, void *context, void *page)
 		return -EPIPE;
 
 	cairo_surface_mark_dirty(p->surface);
-	gtk_image_set_from_surface(GTK_IMAGE(c->image), p->surface);
+	cairo_set_source_surface(c->cairo, p->surface, 0, 0);
+	cairo_set_operator(c->cairo, CAIRO_OPERATOR_SOURCE); 
+	cairo_rectangle(c->cairo, 0, 0, c->width, c->height);
+	cairo_fill(c->cairo);
 
 	if (c->resized) {
 		c->resized = 0;