screenshooter: Properly handle multiple outputs.

clients/screenshot.c

@@ -32,14 +32,22 @@
 #include <wayland-client.h>
 #include "screenshooter-client-protocol.h"
 
+#define MAX(X,Y) ((X) > (Y) ? (X) : (Y))
+
 /* The screenshooter is a good example of a custom object exposed by
  * the compositor and serves as a test bed for implementing client
  * side marshalling outside libwayland.so */
 
-static struct wl_output *output;
 static struct wl_shm *shm;
 static struct screenshooter *screenshooter;
-static int output_width, output_height;
+static struct wl_list output_list;
+
+struct screenshooter_output {
+	struct wl_output *output;
+	struct wl_buffer *buffer;
+	int width, height, offset_x, offset_y;
+	struct wl_list link;
+};
 
 static void
 display_handle_geometry(void *data,
@@ -52,6 +60,14 @@ display_handle_geometry(void *data,
 			const char *make,
 			const char *model)
 {
+	struct screenshooter_output *output;
+
+	output = wl_output_get_user_data(wl_output);
+
+	if (wl_output == output->output) {
+		output->offset_x = x;
+		output->offset_y = y;
+	}
 }
 
 static void
@@ -62,8 +78,15 @@ display_handle_mode(void *data,
 		    int height,
 		    int refresh)
 {
-	output_width = width;
-	output_height = height;
+	struct screenshooter_output *output;
+
+	output = wl_output_get_user_data(wl_output);
+
+	if (wl_output == output->output &&
+			(flags & WL_OUTPUT_MODE_CURRENT)) {
+		output->width = width;
+		output->height = height;
+	}
 }
 
 static const struct wl_output_listener output_listener = {
@@ -75,9 +98,13 @@ static void
 handle_global(struct wl_display *display, uint32_t id,
 	      const char *interface, uint32_t version, void *data)
 {
+	static struct screenshooter_output *output;
+
 	if (strcmp(interface, "wl_output") == 0) {
-		output = wl_display_bind(display, id, &wl_output_interface);
-		wl_output_add_listener(output, &output_listener, NULL);
+		output = malloc(sizeof *output);
+		output->output = wl_display_bind(display, id, &wl_output_interface);
+		wl_list_insert(&output_list, &output->link);
+		wl_output_add_listener(output->output, &output_listener, output);
 	} else if (strcmp(interface, "wl_shm") == 0) {
 		shm = wl_display_bind(display, id, &wl_shm_interface);
 	} else if (strcmp(interface, "screenshooter") == 0) {
@@ -144,6 +171,8 @@ int main(int argc, char *argv[])
 	struct wl_display *display;
 	struct wl_buffer *buffer;
 	void *data = NULL;
+	struct screenshooter_output *output, *next;
+	int ss_area_width = 0, ss_area_height = 0, num_outputs = 0;
 
 	display = wl_display_connect(NULL);
 	if (display == NULL) {
@@ -151,6 +180,7 @@ int main(int argc, char *argv[])
 		return -1;
 	}
 
+	wl_list_init(&output_list);
 	wl_display_add_global_listener(display, handle_global, &screenshooter);
 	wl_display_iterate(display, WL_DISPLAY_READABLE);
 	wl_display_roundtrip(display);
@@ -159,11 +189,32 @@ int main(int argc, char *argv[])
 		return -1;
 	}
 
-	buffer = create_shm_buffer(output_width, output_height, &data);
-	screenshooter_shoot(screenshooter, output, buffer);
+	wl_list_for_each(output, &output_list, link) {
+
+		if (!num_outputs) {
+			ss_area_width = output->width + output->offset_x;
+			ss_area_height = output->height + output->offset_y;
+		}
+		else {
+			ss_area_width = MAX(ss_area_width, output->offset_x + output->width);
+			ss_area_height = MAX(ss_area_height, output->offset_y + output->height);
+		}
+		num_outputs++;
+	}
+
+	buffer = create_shm_buffer(ss_area_width, ss_area_height, &data);
+
+	wl_list_for_each(output, &output_list, link) {
+		screenshooter_shoot(screenshooter, output->output, buffer);
+	}
+
 	wl_display_roundtrip(display);
 
-	write_png(output_width, output_height, data);
+	write_png(ss_area_width, ss_area_height, data);
+
+	wl_list_for_each_safe(output, next, &output_list, link) {
+		free(output);
+	}
 
 	return 0;
 }

src/compositor-drm.c

@@ -1047,6 +1047,20 @@ drm_set_dpms(struct weston_output *output_base, enum dpms_enum level)
 	drmModeFreeConnector(connector);
 }
 
+static void
+drm_output_read_pixels(struct weston_output *output_base, void *data)
+{
+	struct drm_output *output = (struct drm_output *) output_base;
+	struct drm_compositor *compositor =
+		(struct drm_compositor *) output->base.compositor;
+
+	eglMakeCurrent(compositor->base.display, output->egl_surface,
+			output->egl_surface, compositor->base.context);
+
+	glReadPixels(0, 0, output_base->current->width, output_base->current->height,
+				GL_BGRA_EXT, GL_UNSIGNED_BYTE, data);
+}
+
 static int
 create_output_for_connector(struct drm_compositor *ec,
 			    drmModeRes *resources,
@@ -1154,6 +1168,7 @@ create_output_for_connector(struct drm_compositor *ec,
 	output->base.repaint = drm_output_repaint;
 	output->base.destroy = drm_output_destroy;
 	output->base.assign_planes = drm_assign_planes;
+	output->base.read_pixels = drm_output_read_pixels;
 	output->base.set_dpms = drm_set_dpms;
 
 	return 0;

src/compositor-wayland.c

@@ -377,6 +377,20 @@ wayland_output_destroy(struct weston_output *output_base)
 	return;
 }
 
+static void
+wayland_output_read_pixels(struct weston_output *output_base, void *data)
+{
+	struct wayland_output *output = (struct wayland_output *) output_base;
+	struct wayland_compositor *compositor =
+		(struct wayland_compositor *) output->base.compositor;
+
+	eglMakeCurrent(compositor->base.display, output->egl_surface,
+			output->egl_surface, compositor->base.context);
+
+	glReadPixels(0, 0, output_base->current->width, output_base->current->height,
+				GL_BGRA_EXT, GL_UNSIGNED_BYTE, data);
+}
+
 static int
 wayland_compositor_create_output(struct wayland_compositor *c,
 				 int width, int height)
@@ -444,6 +458,7 @@ wayland_compositor_create_output(struct wayland_compositor *c,
 	output->base.repaint = wayland_output_repaint;
 	output->base.destroy = wayland_output_destroy;
 	output->base.assign_planes = NULL;
+	output->base.read_pixels = wayland_output_read_pixels;
 	output->base.set_backlight = NULL;
 	output->base.set_dpms = NULL;
 

src/compositor-x11.c

@@ -344,6 +344,20 @@ x11_output_set_icon(struct x11_compositor *c,
 	pixman_image_unref(image);
 }
 
+static void
+x11_output_read_pixels(struct weston_output *output_base, void *data)
+{
+	struct x11_output *output = (struct x11_output *) output_base;
+	struct x11_compositor *compositor =
+		(struct x11_compositor *) output->base.compositor;
+
+	eglMakeCurrent(compositor->base.display, output->egl_surface,
+			output->egl_surface, compositor->base.context);
+
+	glReadPixels(0, 0, output_base->current->width, output_base->current->height,
+				GL_BGRA_EXT, GL_UNSIGNED_BYTE, data);
+}
+
 static int
 x11_compositor_create_output(struct x11_compositor *c, int x, int y,
 			     int width, int height, int fullscreen)
@@ -454,6 +468,7 @@ x11_compositor_create_output(struct x11_compositor *c, int x, int y,
 	output->base.repaint = x11_output_repaint;
 	output->base.destroy = x11_output_destroy;
 	output->base.assign_planes = NULL;
+	output->base.read_pixels = x11_output_read_pixels;
 	output->base.set_backlight = NULL;
 	output->base.set_dpms = NULL;
 

src/compositor.h

@@ -96,6 +96,7 @@ struct weston_output {
 			pixman_region32_t *damage);
 	void (*destroy)(struct weston_output *output);
 	void (*assign_planes)(struct weston_output *output);
+	void (*read_pixels)(struct weston_output *output, void *data);
 
 	/* backlight values are on 0-255 range, where higher is brighter */
 	uint32_t backlight_current;

src/screenshooter.c

@@ -32,7 +32,7 @@ struct screenshooter {
 	struct weston_compositor *ec;
 	struct wl_global *global;
 	struct wl_client *client;
-	struct weston_process screenshooter_process;
+	struct weston_process process;
 };
 
 static void
@@ -44,7 +44,7 @@ screenshooter_shoot(struct wl_client *client,
 	struct weston_output *output = output_resource->data;
 	struct wl_buffer *buffer = buffer_resource->data;
 	uint8_t *tmp, *d, *s;
-	int32_t stride, i;
+	int32_t buffer_stride, output_stride, i;
 
 	if (!wl_buffer_is_shm(buffer))
 		return;
@@ -53,24 +53,25 @@ screenshooter_shoot(struct wl_client *client,
 	    buffer->height < output->current->height)
 		return;
 
-	stride = wl_shm_buffer_get_stride(buffer);
-	tmp = malloc(stride * buffer->height);
+	buffer_stride = wl_shm_buffer_get_stride(buffer);
+	output_stride = output->current->width * 4;
+	tmp = malloc(output_stride * output->current->height);
 	if (tmp == NULL) {
 		wl_resource_post_no_memory(resource);
 		return;
 	}
 
 	glPixelStorei(GL_PACK_ALIGNMENT, 1);
-	glReadPixels(0, 0, output->current->width, output->current->height,
-		     GL_BGRA_EXT, GL_UNSIGNED_BYTE, tmp);
+	output->read_pixels(output, tmp);
 
-	d = wl_shm_buffer_get_data(buffer);
-	s = tmp + stride * (buffer->height - 1);
+	d = wl_shm_buffer_get_data(buffer) + output->y * buffer_stride +
+							output->x * 4;
+	s = tmp + output_stride * (output->current->height - 1);
 
-	for (i = 0; i < buffer->height; i++) {
-		memcpy(d, s, stride);
-		d += stride;
-		s -= stride;
+	for (i = 0; i < output->current->height; i++) {
+		memcpy(d, s, output_stride);
+		d += buffer_stride;
+		s -= output_stride;
 	}
 
 	free(tmp);
@@ -101,7 +102,7 @@ static void
 screenshooter_sigchld(struct weston_process *process, int status)
 {
 	struct screenshooter *shooter =
-		container_of(process, struct screenshooter, screenshooter_process);
+		container_of(process, struct screenshooter, process);
 
 	shooter->client = NULL;
 }
@@ -116,7 +117,7 @@ screenshooter_binding(struct wl_input_device *device, uint32_t time,
 
 	if (!shooter->client)
 		shooter->client = weston_client_launch(shooter->ec,
-					&shooter->screenshooter_process,
+					&shooter->process,
 					screenshooter_exe, screenshooter_sigchld);
 }