backend-wayland: restructure wayland_output_resize_surface()

A following patch is going to need the introduced 'area' and 'fb_size'
variables. Until then though, a little hack is needed to avoid no-gl
builds failing with error: variable 'fb_size' set but not used.

While starting to use struct weston_geometry, convert also the input and
opaque regions to use it. This shortens and simplifies the code, as we
can drop the roughly duplicate code of doing stuff for with vs. without
a frame.

No change in behavior, this is pure refactoring.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

libweston/backend-wayland/wayland.c

@@ -831,64 +831,54 @@ wayland_output_init_pixman_renderer(struct wayland_output *output)
 static void
 wayland_output_resize_surface(struct wayland_output *output)
 {
-	struct wayland_backend *b =
-		to_wayland_backend(output->base.compositor);
-	int32_t ix, iy, iwidth, iheight;
-	int32_t width, height;
+	struct wayland_backend *b = to_wayland_backend(output->base.compositor);
+	/* Defaults for without frame: */
+	struct weston_size fb_size = {
+		.width = output->base.current_mode->width,
+		.height = output->base.current_mode->height
+	};
+	struct weston_geometry area = {
+		.x = 0,
+		.y = 0,
+		.width = fb_size.width,
+		.height = fb_size.height
+	};
+	struct weston_geometry inp = area;
+	struct weston_geometry opa = area;
 	struct wl_region *region;
 
-	width = output->base.current_mode->width;
-	height = output->base.current_mode->height;
-
 	if (output->frame) {
-		frame_resize_inside(output->frame, width, height);
-
-		frame_input_rect(output->frame, &ix, &iy, &iwidth, &iheight);
-		region = wl_compositor_create_region(b->parent.compositor);
-		wl_region_add(region, ix, iy, iwidth, iheight);
-		wl_surface_set_input_region(output->parent.surface, region);
-		wl_region_destroy(region);
-
-		if (output->parent.xdg_surface) {
-			xdg_surface_set_window_geometry(output->parent.xdg_surface,
-							ix,
-							iy,
-							iwidth,
-							iheight);
-		}
+		frame_resize_inside(output->frame, area.width, area.height);
+		frame_interior(output->frame, &area.x, &area.y, NULL, NULL);
+		fb_size.width = frame_width(output->frame);
+		fb_size.height = frame_height(output->frame);
 
-		frame_opaque_rect(output->frame, &ix, &iy, &iwidth, &iheight);
-		region = wl_compositor_create_region(b->parent.compositor);
-		wl_region_add(region, ix, iy, iwidth, iheight);
-		wl_surface_set_opaque_region(output->parent.surface, region);
-		wl_region_destroy(region);
+		frame_input_rect(output->frame, &inp.x, &inp.y,
+				 &inp.width, &inp.height);
+		frame_opaque_rect(output->frame, &opa.x, &opa.y,
+				  &opa.width, &opa.height);
+	}
 
-		width = frame_width(output->frame);
-		height = frame_height(output->frame);
-	} else {
-		region = wl_compositor_create_region(b->parent.compositor);
-		wl_region_add(region, 0, 0, width, height);
-		wl_surface_set_input_region(output->parent.surface, region);
-		wl_region_destroy(region);
-
-		region = wl_compositor_create_region(b->parent.compositor);
-		wl_region_add(region, 0, 0, width, height);
-		wl_surface_set_opaque_region(output->parent.surface, region);
-		wl_region_destroy(region);
-
-		if (output->parent.xdg_surface) {
-			xdg_surface_set_window_geometry(output->parent.xdg_surface,
-							0,
-							0,
-							width,
-							height);
-		}
+	region = wl_compositor_create_region(b->parent.compositor);
+	wl_region_add(region, inp.x, inp.y, inp.width, inp.height);
+	wl_surface_set_input_region(output->parent.surface, region);
+	wl_region_destroy(region);
+
+	if (output->parent.xdg_surface) {
+		xdg_surface_set_window_geometry(output->parent.xdg_surface,
+						inp.x, inp.y,
+						inp.width, inp.height);
 	}
 
+	region = wl_compositor_create_region(b->parent.compositor);
+	wl_region_add(region, opa.x, opa.y, opa.width, opa.height);
+	wl_surface_set_opaque_region(output->parent.surface, region);
+	wl_region_destroy(region);
+
 #ifdef ENABLE_EGL
 	if (output->gl.egl_window) {
 		wl_egl_window_resize(output->gl.egl_window,
-				     width, height, 0, 0);
+				     fb_size.width, fb_size.height, 0, 0);
 
 		/* These will need to be re-created due to the resize */
 		gl_renderer->output_set_border(&output->base,