pixman-renderer: Move shadow buffer into renderer

The X11 backend uses a shadow buffer to be able to support transformed
outputs. However, this belongs in the renderer, since otherwise this
code would have to be copied into every backend that uses the pixman
renderer and supports transformed outputs.

src/compositor-x11.c

@@ -116,10 +116,8 @@ struct x11_output {
 	xcb_gc_t		gc;
 	xcb_shm_seg_t		segment;
 	pixman_image_t	       *hw_surface;
-	pixman_image_t         *shadow_surface;
 	int			shm_id;
 	void		       *buf;
-	void		       *shadow_buf;
 	uint8_t			depth;
 };
 
@@ -342,59 +340,12 @@ x11_output_repaint_shm(struct weston_output *output_base,
 	struct x11_output *output = (struct x11_output *)output_base;
 	struct weston_compositor *ec = output->base.compositor;
 	struct x11_compositor *c = (struct x11_compositor *)ec;
-	pixman_box32_t *rects;
-	int nrects, i, src_x, src_y, x1, y1, x2, y2, width, height;
 	xcb_void_cookie_t cookie;
 	xcb_generic_error_t *err;
 
-	pixman_renderer_output_set_buffer(output_base, output->shadow_surface);
+	pixman_renderer_output_set_buffer(output_base, output->hw_surface);
 	ec->renderer->repaint_output(output_base, damage);
 
-	width = pixman_image_get_width(output->shadow_surface);
-	height = pixman_image_get_height(output->shadow_surface);
-	rects = pixman_region32_rectangles(damage, &nrects);
-	for (i = 0; i < nrects; i++) {
-		switch (output_base->transform) {
-		default:
-		case WL_OUTPUT_TRANSFORM_NORMAL:
-			x1 = rects[i].x1;
-			x2 = rects[i].x2;
-			y1 = rects[i].y1;
-			y2 = rects[i].y2;
-			break;
-		case WL_OUTPUT_TRANSFORM_180:
-			x1 = width - rects[i].x2;
-			x2 = width - rects[i].x1;
-			y1 = height - rects[i].y2;
-			y2 = height - rects[i].y1;
-			break;
-		case WL_OUTPUT_TRANSFORM_90:
-			x1 = height - rects[i].y2;
-			x2 = height - rects[i].y1;
-			y1 = rects[i].x1;
-			y2 = rects[i].x2;
-			break;
-		case WL_OUTPUT_TRANSFORM_270:
-			x1 = rects[i].y1;
-			x2 = rects[i].y2;
-			y1 = width - rects[i].x2;
-			y2 = width - rects[i].x1;
-			break;
-		}
-		src_x = x1;
-		src_y = y1;
-
-		pixman_image_composite32(PIXMAN_OP_SRC,
-			output->shadow_surface, /* src */
-			NULL /* mask */,
-			output->hw_surface, /* dest */
-			src_x, src_y, /* src_x, src_y */
-			0, 0, /* mask_x, mask_y */
-			x1, y1, /* dest_x, dest_y */
-			x2 - x1, /* width */
-			y2 - y1 /* height */);
-	}
-
 	pixman_region32_subtract(&ec->primary_plane.damage,
 				 &ec->primary_plane.damage, damage);
 	cookie = xcb_shm_put_image_checked(c->conn, output->window, output->gc,
@@ -444,10 +395,6 @@ x11_output_deinit_shm(struct x11_compositor *c, struct x11_output *output)
 		free(err);
 	}
 	shmdt(output->buf);
-
-	pixman_image_unref(output->shadow_surface);
-	output->shadow_surface = NULL;
-	free(output->shadow_buf);
 }
 
 static void
@@ -622,8 +569,6 @@ x11_output_init_shm(struct x11_compositor *c, struct x11_output *output,
 	xcb_format_iterator_t fmt;
 	xcb_void_cookie_t cookie;
 	xcb_generic_error_t *err;
-	int shadow_width, shadow_height;
-	pixman_transform_t transform;
 	const xcb_query_extension_reply_t *ext;
 	int bitsperpixel = 0;
 	pixman_format_code_t pixman_format;
@@ -701,53 +646,6 @@ x11_output_init_shm(struct x11_compositor *c, struct x11_output *output,
 	/* Now create pixman image */
 	output->hw_surface = pixman_image_create_bits(pixman_format, width, height, output->buf,
 		width * (bitsperpixel / 8));
-	pixman_transform_init_identity(&transform);
-	switch (output->base.transform) {
-	default:
-	case WL_OUTPUT_TRANSFORM_NORMAL:
-		shadow_width = width;
-		shadow_height = height;
-		pixman_transform_rotate(&transform,
-			NULL, 0, 0);
-		pixman_transform_translate(&transform, NULL,
-			0, 0);
-		break;
-	case WL_OUTPUT_TRANSFORM_180:
-		shadow_width = width;
-		shadow_height = height;
-		pixman_transform_rotate(&transform,
-			NULL, -pixman_fixed_1, 0);
-		pixman_transform_translate(NULL, &transform,
-			pixman_int_to_fixed(shadow_width),
-			pixman_int_to_fixed(shadow_height));
-		break;
-	case WL_OUTPUT_TRANSFORM_270:
-		shadow_width = height;
-		shadow_height = width;
-		pixman_transform_rotate(&transform,
-			NULL, 0, pixman_fixed_1);
-		pixman_transform_translate(&transform,
-			NULL,
-			pixman_int_to_fixed(shadow_width),
-			0);
-		break;
-	case WL_OUTPUT_TRANSFORM_90:
-		shadow_width = height;
-		shadow_height = width;
-		pixman_transform_rotate(&transform,
-			NULL, 0, -pixman_fixed_1);
-		pixman_transform_translate(&transform,
-			NULL,
-			0,
-			pixman_int_to_fixed(shadow_height));
-		break;
-	}
-	output->shadow_buf = malloc(width * height *  (bitsperpixel / 8));
-	output->shadow_surface = pixman_image_create_bits(pixman_format, shadow_width, shadow_height,
-		output->shadow_buf, shadow_width * (bitsperpixel / 8));
-	/* No need in transform for normal output */
-	if (output->base.transform != WL_OUTPUT_TRANSFORM_NORMAL)
-		pixman_image_set_transform(output->shadow_surface, &transform);
 
 	output->gc = xcb_generate_id(c->conn);
 	xcb_create_gc(c->conn, output->gc, output->window, 0, NULL);

src/pixman-renderer.c

@@ -31,6 +31,8 @@
 #include <linux/input.h>
 
 struct pixman_output_state {
+	void *shadow_buffer;
+	pixman_image_t *shadow_image;
 	pixman_image_t *hw_buffer;
 };
 
@@ -140,7 +142,7 @@ repaint_region(struct weston_surface *es, struct weston_output *output,
 		pixman_image_composite32(pixman_op,
 			ps->image, /* src */
 			NULL /* mask */,
-			po->hw_buffer, /* dest */
+			po->shadow_image, /* dest */
 			src_x, src_y, /* src_x, src_y */
 			0, 0, /* mask_x, mask_y */
 			rects[i].x1, rects[i].y1, /* dest_x, dest_y */
@@ -153,7 +155,7 @@ repaint_region(struct weston_surface *es, struct weston_output *output,
 		pixman_image_composite32(PIXMAN_OP_OVER,
 			pr->debug_color, /* src */
 			NULL /* mask */,
-			po->hw_buffer, /* dest */
+			po->shadow_image, /* dest */
 			src_x, src_y, /* src_x, src_y */
 			0, 0, /* mask_x, mask_y */
 			rects[i].x1, rects[i].y1, /* dest_x, dest_y */
@@ -219,6 +221,35 @@ repaint_surfaces(struct weston_output *output, pixman_region32_t *damage)
 			draw_surface(surface, output, damage);
 }
 
+static void
+copy_to_hw_buffer(struct weston_output *output, pixman_region32_t *region)
+{
+	struct pixman_output_state *po = get_output_state(output);
+	int nrects, i, width, height;
+	pixman_box32_t *rects;
+	pixman_box32_t b;
+
+	width = pixman_image_get_width(po->shadow_image);
+	height = pixman_image_get_height(po->shadow_image);
+
+	rects = pixman_region32_rectangles(region, &nrects);
+	for (i = 0; i < nrects; i++) {
+		b = weston_transformed_rect(width, height,
+					    output->transform, rects[i]);
+
+		pixman_image_composite32(PIXMAN_OP_SRC,
+			po->shadow_image, /* src */
+			NULL /* mask */,
+			po->hw_buffer, /* dest */
+			b.x1, b.y1, /* src_x, src_y */
+			0, 0, /* mask_x, mask_y */
+			b.x1, b.y1, /* dest_x, dest_y */
+			b.x2 - b.x1, /* width */
+			b.y2 - b.y1 /* height */);
+	}
+
+}
+
 static void
 pixman_renderer_repaint_output(struct weston_output *output,
 			     pixman_region32_t *output_damage)
@@ -229,6 +260,7 @@ pixman_renderer_repaint_output(struct weston_output *output,
 		return;
 
 	repaint_surfaces(output, output_damage);
+	copy_to_hw_buffer(output, output_damage);
 
 	pixman_region32_copy(&output->previous_damage, output_damage);
 	wl_signal_emit(&output->frame_signal, output);
@@ -402,10 +434,68 @@ WL_EXPORT int
 pixman_renderer_output_create(struct weston_output *output)
 {
 	struct pixman_output_state *po = calloc(1, sizeof *po);
+	pixman_transform_t transform;
+	pixman_fixed_t fw, fh;
+	int w, h;
+	int rotated = 0;
 
 	if (!po)
 		return -1;
 
+	/* set shadow image transformation */
+	w = output->current->width;
+	h = output->current->height;
+
+	fw = pixman_int_to_fixed(w);
+	fh = pixman_int_to_fixed(h);
+
+	pixman_transform_init_identity(&transform);
+
+	switch (output->transform) {
+	default:
+	case WL_OUTPUT_TRANSFORM_NORMAL:
+		break;
+	case WL_OUTPUT_TRANSFORM_180:
+		pixman_transform_rotate(&transform, NULL, -pixman_fixed_1, 0);
+		pixman_transform_translate(NULL, &transform, fw, fh);
+		break;
+	case WL_OUTPUT_TRANSFORM_270:
+		rotated = 1;
+		pixman_transform_rotate(&transform, NULL, 0, pixman_fixed_1);
+		pixman_transform_translate(&transform, NULL, fh, 0);
+		break;
+	case WL_OUTPUT_TRANSFORM_90:
+		rotated = 1;
+		pixman_transform_rotate(&transform, NULL, 0, -pixman_fixed_1);
+		pixman_transform_translate(&transform, NULL, 0, fw);
+		break;
+	}
+
+	if (rotated) {
+		int tmp = w;
+		w = h;
+		h = tmp;
+	}
+
+	po->shadow_buffer = malloc(w * h * 4);
+
+	if (!po->shadow_buffer) {
+		free(po);
+		return -1;
+	}
+
+	po->shadow_image =
+		pixman_image_create_bits(PIXMAN_x8r8g8b8, w, h,
+					 po->shadow_buffer, w * 4);
+
+	if (!po->shadow_image) {
+		free(po->shadow_buffer);
+		free(po);
+		return -1;
+	}
+
+	pixman_image_set_transform(po->shadow_image, &transform);
+
 	output->renderer_state = po;
 
 	return 0;
@@ -416,7 +506,10 @@ pixman_renderer_output_destroy(struct weston_output *output)
 {
 	struct pixman_output_state *po = get_output_state(output);
 
+	pixman_image_unref(po->shadow_image);
 	pixman_image_unref(po->hw_buffer);
+
+	po->shadow_image = NULL;
 	po->hw_buffer = NULL;
 
 	free(po);