Merge pull request #1069 from emersion/screencopy

Add wlr-screencopy-unstable-v1 support

backend/drm/drm.c

@@ -683,7 +683,7 @@ static bool drm_connector_set_cursor(struct wlr_output *output,
 		wlr_render_texture_with_matrix(rend, texture, matrix, 1.0);
 		wlr_renderer_end(rend);
 
-		wlr_renderer_read_pixels(rend, WL_SHM_FORMAT_ARGB8888, bo_stride,
+		wlr_renderer_read_pixels(rend, WL_SHM_FORMAT_ARGB8888, NULL, bo_stride,
 			plane->surf.width, plane->surf.height, 0, 0, 0, 0, bo_data);
 
 		swap_drm_surface_buffers(&plane->surf, NULL);

examples/meson.build

@@ -1,6 +1,8 @@
 threads = dependency('threads')
 wayland_cursor = dependency('wayland-cursor')
 
+libpng = dependency('libpng', required: false)
+
 # These versions correspond to ffmpeg 4.0
 libavutil = dependency('libavutil', version: '>=56.14.100', required: false)
 libavcodec = dependency('libavcodec', version: '>=58.18.100', required: false)
@@ -56,3 +58,11 @@ if libavutil.found() and libavcodec.found() and libavformat.found()
 				libavformat, wlroots, threads ]
 	)
 endif
+
+if libpng.found()
+	executable(
+		'screencopy',
+		'screencopy.c',
+		dependencies: [wayland_client, wlr_protos, wlroots, libpng]
+	)
+endif

examples/screencopy.c

@@ -0,0 +1,270 @@
+/*
+ * Copyright © 2008 Kristian Høgsberg
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#define _XOPEN_SOURCE 700
+#define _POSIX_C_SOURCE 199309L
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <png.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/param.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <wayland-client-protocol.h>
+#include "wlr-screencopy-unstable-v1-client-protocol.h"
+
+struct format {
+	enum wl_shm_format wl_format;
+	bool is_bgr;
+};
+
+static struct wl_shm *shm = NULL;
+static struct zwlr_screencopy_manager_v1 *screencopy_manager = NULL;
+static struct wl_output *output = NULL;
+
+static struct {
+	struct wl_buffer *wl_buffer;
+	void *data;
+	enum wl_shm_format format;
+	int width, height, stride;
+	bool y_invert;
+} buffer;
+bool buffer_copy_done = false;
+
+// wl_shm_format describes little-endian formats, libpng uses big-endian
+// formats (so Wayland's ABGR is libpng's RGBA).
+static const struct format formats[] = {
+	{WL_SHM_FORMAT_XRGB8888, true},
+	{WL_SHM_FORMAT_ARGB8888, true},
+	{WL_SHM_FORMAT_XBGR8888, false},
+	{WL_SHM_FORMAT_ABGR8888, false},
+};
+
+static int backingfile(off_t size) {
+	char template[] = "/tmp/wlroots-shared-XXXXXX";
+	int fd = mkstemp(template);
+	if (fd < 0) {
+		return -1;
+	}
+
+	int ret;
+	while ((ret = ftruncate(fd, size)) == EINTR) {
+		// No-op
+	}
+	if (ret < 0) {
+		close(fd);
+		return -1;
+	}
+
+	unlink(template);
+	return fd;
+}
+
+static struct wl_buffer *create_shm_buffer(enum wl_shm_format fmt,
+		int width, int height, int stride, void **data_out) {
+	int size = stride * height;
+
+	int fd = backingfile(size);
+	if (fd < 0) {
+		fprintf(stderr, "creating a buffer file for %d B failed: %m\n", size);
+		return NULL;
+	}
+
+	void *data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if (data == MAP_FAILED) {
+		fprintf(stderr, "mmap failed: %m\n");
+		close(fd);
+		return NULL;
+	}
+
+	struct wl_shm_pool *pool = wl_shm_create_pool(shm, fd, size);
+	close(fd);
+	struct wl_buffer *buffer = wl_shm_pool_create_buffer(pool, 0, width, height,
+		stride, fmt);
+	wl_shm_pool_destroy(pool);
+
+	*data_out = data;
+	return buffer;
+}
+
+static void frame_handle_buffer(void *data,
+		struct zwlr_screencopy_frame_v1 *frame, uint32_t format,
+		uint32_t width, uint32_t height, uint32_t stride) {
+	buffer.format = format;
+	buffer.width = width;
+	buffer.height = height;
+	buffer.stride = stride;
+	buffer.wl_buffer =
+		create_shm_buffer(format, width, height, stride, &buffer.data);
+	if (buffer.wl_buffer == NULL) {
+		fprintf(stderr, "failed to create buffer\n");
+		exit(EXIT_FAILURE);
+	}
+
+	zwlr_screencopy_frame_v1_copy(frame, buffer.wl_buffer);
+}
+
+static void frame_handle_flags(void *data,
+		struct zwlr_screencopy_frame_v1 *frame, uint32_t flags) {
+	buffer.y_invert = flags & ZWLR_SCREENCOPY_FRAME_V1_FLAGS_Y_INVERT;
+}
+
+static void frame_handle_ready(void *data,
+		struct zwlr_screencopy_frame_v1 *frame, uint32_t tv_sec_hi,
+		uint32_t tv_sec_lo, uint32_t tv_nsec) {
+	buffer_copy_done = true;
+}
+
+static void frame_handle_failed(void *data,
+		struct zwlr_screencopy_frame_v1 *frame) {
+	fprintf(stderr, "failed to copy frame\n");
+	exit(EXIT_FAILURE);
+}
+
+static const struct zwlr_screencopy_frame_v1_listener frame_listener = {
+	.buffer = frame_handle_buffer,
+	.flags = frame_handle_flags,
+	.ready = frame_handle_ready,
+	.failed = frame_handle_failed,
+};
+
+static void handle_global(void *data, struct wl_registry *registry,
+		uint32_t name, const char *interface, uint32_t version) {
+	if (strcmp(interface, wl_output_interface.name) == 0 && output == NULL) {
+		output = wl_registry_bind(registry, name, &wl_output_interface, 1);
+	} else if (strcmp(interface, wl_shm_interface.name) == 0) {
+		shm = wl_registry_bind(registry, name, &wl_shm_interface, 1);
+	} else if (strcmp(interface,
+			zwlr_screencopy_manager_v1_interface.name) == 0) {
+		screencopy_manager = wl_registry_bind(registry, name,
+			&zwlr_screencopy_manager_v1_interface, 1);
+	}
+}
+
+static void handle_global_remove(void *data, struct wl_registry *registry,
+		uint32_t name) {
+	// Who cares?
+}
+
+static const struct wl_registry_listener registry_listener = {
+	.global = handle_global,
+	.global_remove = handle_global_remove,
+};
+
+static void write_image(char *filename, enum wl_shm_format wl_fmt, int width,
+		int height, int stride, bool y_invert, png_bytep data) {
+	const struct format *fmt = NULL;
+	for (size_t i = 0; i < sizeof(formats) / sizeof(formats[0]); ++i) {
+		if (formats[i].wl_format == wl_fmt) {
+			fmt = &formats[i];
+			break;
+		}
+	}
+	if (fmt == NULL) {
+		fprintf(stderr, "unsupported format %"PRIu32"\n", wl_fmt);
+		exit(EXIT_FAILURE);
+	}
+
+	FILE *f = fopen(filename, "wb");
+	if (f == NULL) {
+		fprintf(stderr, "failed to open output file\n");
+		exit(EXIT_FAILURE);
+	}
+
+	png_structp png =
+		png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+	png_infop info = png_create_info_struct(png);
+
+	png_init_io(png, f);
+
+	png_set_IHDR(png, info, width, height, 8, PNG_COLOR_TYPE_RGBA,
+		PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
+		PNG_FILTER_TYPE_DEFAULT);
+
+	if (fmt->is_bgr) {
+		png_set_bgr(png);
+	}
+
+	png_write_info(png, info);
+
+	for (size_t i = 0; i < (size_t)height; ++i) {
+		png_bytep row;
+		if (y_invert) {
+			row = data + (height - i - 1) * stride;
+		} else {
+			row = data + i * stride;
+		}
+		png_write_row(png, row);
+	}
+
+	png_write_end(png, NULL);
+
+	png_destroy_write_struct(&png, &info);
+
+	fclose(f);
+}
+
+int main(int argc, char *argv[]) {
+	struct wl_display * display = wl_display_connect(NULL);
+	if (display == NULL) {
+		fprintf(stderr, "failed to create display: %m\n");
+		return EXIT_FAILURE;
+	}
+
+	struct wl_registry *registry = wl_display_get_registry(display);
+	wl_registry_add_listener(registry, &registry_listener, NULL);
+	wl_display_dispatch(display);
+	wl_display_roundtrip(display);
+
+	if (shm == NULL) {
+		fprintf(stderr, "compositor is missing wl_shm\n");
+		return EXIT_FAILURE;
+	}
+	if (screencopy_manager == NULL) {
+		fprintf(stderr, "compositor doesn't support wlr-screencopy-unstable-v1\n");
+		return EXIT_FAILURE;
+	}
+	if (output == NULL) {
+		fprintf(stderr, "no output available\n");
+		return EXIT_FAILURE;
+	}
+
+	struct zwlr_screencopy_frame_v1 *frame =
+		zwlr_screencopy_manager_v1_capture_output(screencopy_manager, 0, output);
+	zwlr_screencopy_frame_v1_add_listener(frame, &frame_listener, NULL);
+
+	while (!buffer_copy_done && wl_display_dispatch(display) != -1) {
+		// This space is intentionally left blank
+	}
+
+	write_image("wayland-screenshot.png", buffer.format, buffer.width,
+		buffer.height, buffer.stride, buffer.y_invert, buffer.data);
+	wl_buffer_destroy(buffer.wl_buffer);
+
+	return EXIT_SUCCESS;
+}

include/rootston/desktop.h

@@ -22,6 +22,7 @@
 #include <wlr/types/wlr_list.h>
 #include <wlr/types/wlr_idle.h>
 #include <wlr/types/wlr_idle_inhibit_v1.h>
+#include <wlr/types/wlr_screencopy_v1.h>
 #include "rootston/view.h"
 #include "rootston/config.h"
 #include "rootston/output.h"
@@ -54,6 +55,7 @@ struct roots_desktop {
 	struct wlr_linux_dmabuf *linux_dmabuf;
 	struct wlr_layer_shell *layer_shell;
 	struct wlr_virtual_keyboard_manager_v1 *virtual_keyboard;
+	struct wlr_screencopy_manager_v1 *screencopy;
 
 	struct wl_listener new_output;
 	struct wl_listener layout_change;

include/wlr/render/interface.h

@@ -34,7 +34,7 @@ struct wlr_renderer_impl {
 	int (*get_dmabuf_modifiers)(struct wlr_renderer *renderer, int format,
 		uint64_t **modifiers);
 	bool (*read_pixels)(struct wlr_renderer *renderer, enum wl_shm_format fmt,
-		uint32_t stride, uint32_t width, uint32_t height,
+		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);
 	bool (*format_supported)(struct wlr_renderer *renderer,

include/wlr/render/wlr_renderer.h

@@ -7,6 +7,10 @@
 #include <wlr/render/wlr_texture.h>
 #include <wlr/types/wlr_box.h>
 
+enum wlr_renderer_read_pixels_flags {
+	WLR_RENDERER_READ_PIXELS_Y_INVERT = 1,
+};
+
 struct wlr_renderer_impl;
 
 struct wlr_renderer {
@@ -87,9 +91,12 @@ int wlr_renderer_get_dmabuf_modifiers(struct wlr_renderer *renderer, int format,
 /**
  * Reads out of pixels of the currently bound surface into data. `stride` is in
  * bytes.
+ *
+ * If `flags` is not NULl, the caller indicates that it accepts frame flags
+ * defined in `enum wlr_renderer_read_pixels_flags`.
  */
 bool wlr_renderer_read_pixels(struct wlr_renderer *r, enum wl_shm_format fmt,
-	uint32_t stride, uint32_t width, uint32_t height,
+	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);
 /**
  * Checks if a format is supported.

include/wlr/types/wlr_screencopy_v1.h

@@ -0,0 +1,39 @@
+#ifndef WLR_TYPES_WLR_SCREENCOPY_V1_H
+#define WLR_TYPES_WLR_SCREENCOPY_V1_H
+
+#include <wayland-server.h>
+
+struct wlr_screencopy_manager_v1 {
+	struct wl_global *global;
+	struct wl_list resources; // wl_resource
+	struct wl_list frames; // wlr_screencopy_frame_v1::link
+
+	struct wl_listener display_destroy;
+
+	void *data;
+};
+
+struct wlr_screencopy_frame_v1 {
+	struct wl_resource *resource;
+	struct wlr_screencopy_manager_v1 *manager;
+	struct wl_list link;
+
+	enum wl_shm_format format;
+	struct wlr_box box;
+	int stride;
+
+	struct wl_shm_buffer *buffer;
+	struct wl_listener buffer_destroy;
+
+	struct wlr_output *output;
+	struct wl_listener output_swap_buffers;
+
+	void *data;
+};
+
+struct wlr_screencopy_manager_v1 *wlr_screencopy_manager_v1_create(
+	struct wl_display *display);
+void wlr_screencopy_manager_v1_destroy(
+	struct wlr_screencopy_manager_v1 *screencopy);
+
+#endif