screencopy: add capture_output_region support

include/wlr/types/wlr_screencopy_v1.h

@@ -18,7 +18,7 @@ struct wlr_screencopy_frame_v1 {
 	struct wlr_screencopy_manager_v1 *manager;
 	struct wl_list link;
 
-	int32_t width, height;
+	struct wlr_box buffer_box;
 
 	struct wl_shm_buffer *buffer;
 

protocol/wlr-screencopy-unstable-v1.xml

@@ -43,16 +43,39 @@
       source.
     </description>
 
+    <enum name="error">
+      <entry name="invalid_output_region" value="0"
+        summary="tried to capture an invalid output region"/>
+    </enum>
+
     <request name="capture_output">
-      <description summary="start capturing">
+      <description summary="capture an output">
-        Capture the next frame of a an entire output.
+        Capture the next frame of an entire output.
       </description>
       <arg name="frame" type="new_id" interface="zwlr_screencopy_frame_v1"/>
       <arg name="overlay_cursor" type="int"
-        summary="include custom client hardware cursor on top of the frame"/>
+        summary="composite cursor onto the frame"/>
       <arg name="output" type="object" interface="wl_output"/>
     </request>
 
+    <request name="capture_output_region">
+      <description summary="capture an output's region">
+        Capture the next frame of an output's region.
+
+        The region is given in output logical coordinates, see
+        xdg_output.logical_size. Trying to capture a region spanning outside the
+        output extents is a protocol error.
+      </description>
+      <arg name="frame" type="new_id" interface="zwlr_screencopy_frame_v1"/>
+      <arg name="overlay_cursor" type="int"
+        summary="composite cursor onto the frame"/>
+      <arg name="output" type="object" interface="wl_output"/>
+      <arg name="x" type="int"/>
+      <arg name="y" type="int"/>
+      <arg name="width" type="int"/>
+      <arg name="height" type="int"/>
+    </request>
+
     <request name="destroy" type="destructor">
       <description summary="destroy the manager">
         All objects created by the manager will still remain valid, until their

render/gles2/renderer.c

@@ -253,7 +253,8 @@ static bool gles2_read_pixels(struct wlr_renderer *wlr_renderer,
 		enum wl_shm_format wl_fmt, uint32_t *flags, uint32_t stride,
 		uint32_t width, uint32_t height, uint32_t src_x, uint32_t src_y,
 		uint32_t dst_x, uint32_t dst_y, void *data) {
-	gles2_get_renderer_in_context(wlr_renderer);
+	struct wlr_gles2_renderer *renderer =
+		gles2_get_renderer_in_context(wlr_renderer);
 
 	const struct wlr_gles2_pixel_format *fmt = get_gles2_format_from_wl(wl_fmt);
 	if (fmt == NULL) {
@@ -266,13 +267,15 @@ static bool gles2_read_pixels(struct wlr_renderer *wlr_renderer,
 	// Make sure any pending drawing is finished before we try to read it
 	glFinish();
 
+	glGetError(); // Clear the error flag
+
 	unsigned char *p = data + dst_y * stride;
 	uint32_t pack_stride = width * fmt->bpp / 8;
 	if (pack_stride == stride && dst_x == 0 && flags != NULL) {
 		// Under these particular conditions, we can read the pixels with only
 		// one glReadPixels call
-		glReadPixels(src_x, src_y, width, height, fmt->gl_format,
+		glReadPixels(src_x, renderer->viewport_height - height - src_y,
-			fmt->gl_type, p);
+			width, height, fmt->gl_format, fmt->gl_type, p);
 		*flags = WLR_RENDERER_READ_PIXELS_Y_INVERT;
 	} else {
 		// Unfortunately GLES2 doesn't support GL_PACK_*, so we have to read
@@ -288,7 +291,7 @@ static bool gles2_read_pixels(struct wlr_renderer *wlr_renderer,
 
 	POP_GLES2_DEBUG;
 
-	return true;
+	return (glGetError() == GL_NO_ERROR);
 }
 
 static bool gles2_format_supported(struct wlr_renderer *wlr_renderer,

types/wlr_screencopy_v1.c

@@ -28,10 +28,8 @@ static void frame_handle_output_swap_buffers(struct wl_listener *listener,
 	wl_list_remove(&frame->output_swap_buffers.link);
 	wl_list_init(&frame->output_swap_buffers.link);
 
-	if (output->width != frame->width || output->height != frame->height) {
+	int x = frame->buffer_box.x;
-		zwlr_screencopy_frame_v1_send_failed(frame->resource);
+	int y = frame->buffer_box.y;
-		return;
-	}
 
 	struct wl_shm_buffer *buffer = frame->buffer;
 	assert(buffer != NULL);
@@ -45,7 +43,7 @@ static void frame_handle_output_swap_buffers(struct wl_listener *listener,
 	void *data = wl_shm_buffer_get_data(buffer);
 	uint32_t flags = 0;
 	bool ok = wlr_renderer_read_pixels(renderer, fmt, &flags, stride,
-		width, height, 0, 0, 0, 0, data);
+		width, height, x, y, 0, 0, data);
 	wl_shm_buffer_end_access(buffer);
 
 	if (!ok) {
@@ -84,8 +82,8 @@ static void frame_handle_copy(struct wl_client *client,
 		return;
 	}
 
-	if (frame->width != wl_shm_buffer_get_width(buffer) ||
+	if (frame->buffer_box.width != wl_shm_buffer_get_width(buffer) ||
-			frame->height != wl_shm_buffer_get_height(buffer)) {
+			frame->buffer_box.height != wl_shm_buffer_get_height(buffer)) {
 		wl_resource_post_error(frame->resource,
 			ZWLR_SCREENCOPY_FRAME_V1_ERROR_INVALID_DIMENSIONS,
 			"invalid width or height");
@@ -139,24 +137,37 @@ static struct wlr_screencopy_manager_v1 *manager_from_resource(
 	return wl_resource_get_user_data(resource);
 }
 
-static void manager_handle_capture_output(struct wl_client *client,
+static void capture_output(struct wl_client *client,
-		struct wl_resource *manager_resource, uint32_t id,
+		struct wlr_screencopy_manager_v1 *manager, uint32_t version, uint32_t id,
-		int32_t overlay_cursor, struct wl_resource *output_resource) {
+		int32_t overlay_cursor, struct wlr_output *output,
-	struct wlr_screencopy_manager_v1 *manager =
+		const struct wlr_box *box) {
-		manager_from_resource(manager_resource);
+	struct wlr_box buffer_box = {0};
-	struct wlr_output *output = wlr_output_from_resource(output_resource);
+	if (box == NULL) {
+		buffer_box.width = output->width;
+		buffer_box.height = output->height;
+	} else {
+		int ow, oh;
+		wlr_output_effective_resolution(output, &ow, &oh);
+
+		buffer_box = *box;
+
+		wlr_box_transform(&buffer_box, output->transform, ow, oh, &buffer_box);
+		buffer_box.x *= output->scale;
+		buffer_box.y *= output->scale;
+		buffer_box.width *= output->scale;
+		buffer_box.height *= output->scale;
+	}
 
 	struct wlr_screencopy_frame_v1 *frame =
 		calloc(1, sizeof(struct wlr_screencopy_frame_v1));
 	if (frame == NULL) {
-		wl_resource_post_no_memory(manager_resource);
+		wl_client_post_no_memory(client);
 		return;
 	}
 	frame->manager = manager;
 
 	frame->output = output;
 
-	uint32_t version = wl_resource_get_version(manager_resource);
 	frame->resource = wl_resource_create(client,
 		&zwlr_screencopy_frame_v1_interface, version, id);
 	if (frame->resource == NULL) {
@@ -171,11 +182,39 @@ static void manager_handle_capture_output(struct wl_client *client,
 
 	wl_list_init(&frame->output_swap_buffers.link);
 
-	frame->width = output->width;
+	frame->buffer_box = buffer_box;
-	frame->height = output->height;
-	// TODO: don't send zero
 	zwlr_screencopy_frame_v1_send_buffer(frame->resource,
-		frame->width, frame->height, 0, 0);
+		frame->buffer_box.width, frame->buffer_box.height,
+		WL_SHM_FORMAT_XRGB8888, 4 * frame->buffer_box.width);
+}
+
+static void manager_handle_capture_output(struct wl_client *client,
+		struct wl_resource *manager_resource, uint32_t id,
+		int32_t overlay_cursor, struct wl_resource *output_resource) {
+	struct wlr_screencopy_manager_v1 *manager =
+		manager_from_resource(manager_resource);
+	uint32_t version = wl_resource_get_version(manager_resource);
+	struct wlr_output *output = wlr_output_from_resource(output_resource);
+
+	capture_output(client, manager, version, id, overlay_cursor, output, NULL);
+}
+
+static void manager_handle_capture_output_region(struct wl_client *client,
+		struct wl_resource *manager_resource, uint32_t id,
+		int32_t overlay_cursor, struct wl_resource *output_resource,
+		int32_t x, int32_t y, int32_t width, int32_t height) {
+	struct wlr_screencopy_manager_v1 *manager =
+		manager_from_resource(manager_resource);
+	uint32_t version = wl_resource_get_version(manager_resource);
+	struct wlr_output *output = wlr_output_from_resource(output_resource);
+
+	struct wlr_box box = {
+		.x = x,
+		.y = y,
+		.width = width,
+		.height = height,
+	};
+	capture_output(client, manager, version, id, overlay_cursor, output, &box);
 }
 
 static void manager_handle_destroy(struct wl_client *client,
@@ -185,6 +224,7 @@ static void manager_handle_destroy(struct wl_client *client,
 
 static const struct zwlr_screencopy_manager_v1_interface manager_impl = {
 	.capture_output = manager_handle_capture_output,
+	.capture_output_region = manager_handle_capture_output_region,
 	.destroy = manager_handle_destroy,
 };