render/pixman: add wlr_*_is_pixman and wlr_pixman_texture_get_image

Add the following functions:

- wlr_renderer_is_pixman
- wlr_texture_is_pixman
- wlr_pixman_texture_get_image

include/wlr/render/pixman.h

@@ -9,9 +9,14 @@
 #ifndef WLR_RENDER_PIXMAN_H
 #define WLR_RENDER_PIXMAN_H
 
+#include <pixman.h>
 #include <wlr/backend.h>
 #include <wlr/render/wlr_renderer.h>
 
 struct wlr_renderer *wlr_pixman_renderer_create(void);
 
+bool wlr_renderer_is_pixman(struct wlr_renderer *wlr_renderer);
+bool wlr_texture_is_pixman(struct wlr_texture *texture);
+pixman_image_t *wlr_pixman_texture_get_image(struct wlr_texture *wlr_texture);
+
 #endif

render/pixman/renderer.c

@@ -12,9 +12,13 @@
 
 static const struct wlr_renderer_impl renderer_impl;
 
+bool wlr_renderer_is_pixman(struct wlr_renderer *wlr_renderer) {
+	return wlr_renderer->impl == &renderer_impl;
+}
+
 static struct wlr_pixman_renderer *get_renderer(
 		struct wlr_renderer *wlr_renderer) {
-	assert(wlr_renderer->impl == &renderer_impl);
+	assert(wlr_renderer_is_pixman(wlr_renderer));
 	return (struct wlr_pixman_renderer *)wlr_renderer;
 }
 
@@ -31,9 +35,13 @@ static struct wlr_pixman_buffer *get_buffer(
 
 static const struct wlr_texture_impl texture_impl;
 
+bool wlr_texture_is_pixman(struct wlr_texture *texture) {
+	return texture->impl == &texture_impl;
+}
+
 static struct wlr_pixman_texture *get_texture(
 		struct wlr_texture *wlr_texture) {
-	assert(wlr_texture->impl == &texture_impl);
+	assert(wlr_texture_is_pixman(wlr_texture));
 	return (struct wlr_pixman_texture *)wlr_texture;
 }
 
@@ -554,3 +562,8 @@ struct wlr_renderer *wlr_pixman_renderer_create(void) {
 
 	return &renderer->wlr_renderer;
 }
+
+pixman_image_t *wlr_pixman_texture_get_image(struct wlr_texture *wlr_texture) {
+	struct wlr_pixman_texture *texture = get_texture(wlr_texture);
+	return texture->image;
+}