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ShellScreenGrabber: grab the screen using pixel buffers

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For the Intel drivers, using glReadPixels() to read into client-memory
directly from the frame buffer is much slower than creating a pixel
buffer, copying into that, and then mapping that for reading. On other
drivers, the two approaches are likely to be similar in speed. Create
a ShellScreenGrabber abstraction that uses pixel buffers if available.
Use that for screenshots and screen recording.

https://bugzilla.gnome.org/show_bug.cgi?id=669065
This commit is contained in:
Owen W. Taylor
2012-01-27 16:33:26 -05:00
parent b3936ecadf
commit 4e89a5edde
6 changed files with 292 additions and 29 deletions
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50
src/shell-global.c
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@ -35,6 +35,7 @@
#include "shell-global-private.h"
#include "shell-jsapi-compat-private.h"
#include "shell-perf-log.h"
#include "shell-screen-grabber.h"
#include "shell-window-tracker.h"
#include "shell-wm.h"
#include "st.h"
@ -1989,25 +1990,38 @@ write_screenshot_thread (GSimpleAsyncResult *result,
g_simple_async_result_set_op_res_gboolean (result, status == CAIRO_STATUS_SUCCESS);
}
static void
do_grab_screenshot (_screenshot_data *screenshot_data,
int x,
int y,
int width,
int height)
{
ShellScreenGrabber *grabber;
static const cairo_user_data_key_t key;
guchar *data;
grabber = shell_screen_grabber_new ();
data = shell_screen_grabber_grab (grabber, x, y, width, height);
g_object_unref (grabber);
screenshot_data->image = cairo_image_surface_create_for_data (data, CAIRO_FORMAT_RGB24,
width, height, width * 4);
cairo_surface_set_user_data (screenshot_data->image, &key,
data, (cairo_destroy_func_t)g_free);
}
static void
grab_screenshot (ClutterActor *stage,
_screenshot_data *screenshot_data)
{
MetaScreen *screen = shell_global_get_screen (screenshot_data->global);
guchar *data;
int width, height;
GSimpleAsyncResult *result;
meta_plugin_query_screen_size (screenshot_data->global->plugin, &width, &height);
screenshot_data->image = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, width, height);
data = cairo_image_surface_get_data (screenshot_data->image);
cogl_flush();
cogl_read_pixels (0, 0, width, height, COGL_READ_PIXELS_COLOR_BUFFER, CLUTTER_CAIRO_FORMAT_ARGB32, data);
cairo_surface_mark_dirty (screenshot_data->image);
do_grab_screenshot (screenshot_data, 0, 0, width, height);
if (meta_screen_get_n_monitors (screen) > 1)
{
@ -2064,20 +2078,12 @@ grab_area_screenshot (ClutterActor *stage,
_screenshot_data *screenshot_data)
{
GSimpleAsyncResult *result;
guchar *data;
screenshot_data->image = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
screenshot_data->screenshot_area.width,
screenshot_data->screenshot_area.height);
data = cairo_image_surface_get_data (screenshot_data->image);
cogl_flush();
cogl_read_pixels (screenshot_data->screenshot_area.x, screenshot_data->screenshot_area.y,
screenshot_data->screenshot_area.width, screenshot_data->screenshot_area.height,
COGL_READ_PIXELS_COLOR_BUFFER, CLUTTER_CAIRO_FORMAT_ARGB32, data);
cairo_surface_mark_dirty (screenshot_data->image);
do_grab_screenshot (screenshot_data,
screenshot_data->screenshot_area.x,
screenshot_data->screenshot_area.y,
screenshot_data->screenshot_area.width,
screenshot_data->screenshot_area.height);
g_signal_handlers_disconnect_by_func (stage, (void *)grab_area_screenshot, (gpointer)screenshot_data);
result = g_simple_async_result_new (NULL, on_screenshot_written, (gpointer)screenshot_data, grab_area_screenshot);