[PATCH] screenshooter: Properly handle multiple outputs.

Kristian Hoegsberg hoegsberg at gmail.com
Wed Apr 4 05:37:45 PDT 2012


On Wed, Apr 04, 2012 at 01:51:08AM -0600, Scott Moreau wrote:
> ---

Looks pretty good.  There are a few small comments below, but the
overall approach is good.

> Tested: Side-by-side and stacked output configurations, in x11 and drm.
> Shooting under drm glitches sometimes and either or both output data
> contains garbage.

I see the drm glitches without this, it's a different problem.

> 
>  clients/screenshot.c     |   69 ++++++++++++++++++++++++++++++++++++++++------
>  src/compositor-drm.c     |   14 +++++++++
>  src/compositor-wayland.c |   14 +++++++++
>  src/compositor-x11.c     |   14 +++++++++
>  src/compositor.h         |    1 +
>  src/screenshooter.c      |   28 +++++++++---------
>  6 files changed, 117 insertions(+), 23 deletions(-)
> 
> diff --git a/clients/screenshot.c b/clients/screenshot.c
> index 6cc2ebb..40f0af4 100644
> --- a/clients/screenshot.c
> +++ b/clients/screenshot.c
> @@ -32,14 +32,24 @@
>  #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 ss_output {
> +	struct wl_output *output;
> +	struct wl_buffer *buffer;
> +	int width, height, offset_x, offset_y;
> +	struct wl_list link;
> +};
> +
> +static struct ss_output *output;

Can we call this screenshooter_output instead?

>  static void
>  display_handle_geometry(void *data,
> @@ -52,6 +62,14 @@ display_handle_geometry(void *data,
>  			const char *make,
>  			const char *model)
>  {
> +	struct ss_output *ss_output;
> +
> +	wl_list_for_each(ss_output, &output_list, link) {
> +		if (wl_output == ss_output->output) {
> +			ss_output->offset_x = x;
> +			ss_output->offset_y = y;
> +		}
> +	}

Instead of this loop, you can just set the user data on the wl_output
object (the data arg to add_listener) and then get it here using

  ss_output = wl_output_get_user_data(wl_output);


>  }
>  
>  static void
> @@ -62,8 +80,15 @@ display_handle_mode(void *data,
>  		    int height,
>  		    int refresh)
>  {
> -	output_width = width;
> -	output_height = height;
> +	struct ss_output *ss_output;
> +
> +	wl_list_for_each(ss_output, &output_list, link) {
> +		if (wl_output == ss_output->output &&
> +				(flags & WL_OUTPUT_MODE_CURRENT)) {
> +			ss_output->width = width;
> +			ss_output->height = height;
> +		}
> +	}

Same here.

>  }
>  
>  static const struct wl_output_listener output_listener = {
> @@ -76,8 +101,10 @@ handle_global(struct wl_display *display, uint32_t id,
>  	      const char *interface, uint32_t version, void *data)
>  {
>  	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, NULL);

Pass output instead of NULL as the last arg here.

>  	} 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 ss_output *ss_output;
> +	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(ss_output, &output_list, link) {
> +
> +		if (!num_outputs) {
> +			ss_area_width = ss_output->width + ss_output->offset_x;
> +			ss_area_height = ss_output->height + ss_output->offset_y;
> +		}

I'd just set ss_area_width/height to 0 initially.


> +		else {
> +			ss_area_width = MAX(ss_area_width, ss_output->offset_x + ss_output->width);
> +			ss_area_height = MAX(ss_area_height, ss_output->offset_y + ss_output->height);
> +		}
> +		num_outputs++;
> +	}
> +
> +	buffer = create_shm_buffer(ss_area_width, ss_area_height, &data);
> +
> +	wl_list_for_each(ss_output, &output_list, link) {
> +		screenshooter_shoot(screenshooter, ss_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(ss_output, &output_list, link) {
> +		free(ss_output);

You need wl_list_for_each_safe here since you're freeing the structs
that holds the prev/next pointers.

> +	}
>  
>  	return 0;
>  }
> diff --git a/src/compositor-drm.c b/src/compositor-drm.c
> index d428c82..7f2886e 100644
> --- a/src/compositor-drm.c
> +++ b/src/compositor-drm.c
> @@ -1047,6 +1047,19 @@ 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,
> @@ -1085,6 +1098,7 @@ create_output_for_connector(struct drm_compositor *ec,
>  	output->base.subpixel = drm_subpixel_to_wayland(connector->subpixel);
>  	output->base.make = "unknown";
>  	output->base.model = "unknown";
> +	output->base.read_pixels = drm_output_read_pixels;

Group this assignment with the other function pointer assignments
(repaint, destroy etc, at the end of the function).

>  	wl_list_init(&output->base.mode_list);
>  
>  	output->crtc_id = resources->crtcs[i];
> diff --git a/src/compositor-wayland.c b/src/compositor-wayland.c
> index 593e272..8c87721 100644
> --- a/src/compositor-wayland.c
> +++ b/src/compositor-wayland.c
> @@ -377,6 +377,19 @@ 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)
> @@ -393,6 +406,7 @@ wayland_compositor_create_output(struct wayland_compositor *c,
>  	output->mode.width = width;
>  	output->mode.height = height;
>  	output->mode.refresh = 60;
> +	output->base.read_pixels = wayland_output_read_pixels;
>  	wl_list_init(&output->base.mode_list);
>  	wl_list_insert(&output->base.mode_list, &output->mode.link);
>  
> diff --git a/src/compositor-x11.c b/src/compositor-x11.c
> index d0203ca..09aa117 100644
> --- a/src/compositor-x11.c
> +++ b/src/compositor-x11.c
> @@ -344,6 +344,19 @@ 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)
> @@ -381,6 +394,7 @@ x11_compositor_create_output(struct x11_compositor *c, int x, int y,
>  	output->mode.width = width;
>  	output->mode.height = height;
>  	output->mode.refresh = 60;
> +	output->base.read_pixels = x11_output_read_pixels;
>  	wl_list_init(&output->base.mode_list);
>  	wl_list_insert(&output->base.mode_list, &output->mode.link);
>  
> diff --git a/src/compositor.h b/src/compositor.h
> index d1cd7c8..ea18b7b 100644
> --- a/src/compositor.h
> +++ b/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;
> diff --git a/src/screenshooter.c b/src/screenshooter.c
> index f9497f7..3fe7bc3 100644
> --- a/src/screenshooter.c
> +++ b/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 +53,24 @@ 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;

Just add output->x * 4 term to d here instead of inside the loop.

> +	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 + output->x * 4, s, output_stride);
> +		d += buffer_stride;
> +		s -= output_stride;
>  	}
>  
>  	free(tmp);
> @@ -101,7 +101,7 @@ 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 +116,7 @@ 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);
>  }
>  
> -- 
> 1.7.4.1
> 
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