GdkPixbuf is stored in memory as individual bytes, in strict red-green-blue-alpha
order, while cairo image surfaces are stored as 32bits units whose
order depends on the endianess.
It is probably possible to do something better, taking advantage
of cogl and the GL using the actual component order, but for now
it is easier to use the GDK utility to convert the cairo surface.
https://bugzilla.gnome.org/show_bug.cgi?id=693931
Use GdkPixbuf rather then cairo_surface_write_to_png_stream when saving
screenshots because this allows us to embedded metadata into the file which
is used by the background control panel to filter out screenshots.
https://bugzilla.gnome.org/show_bug.cgi?id=693737
We have to mark the cairo_surface dirty after modifying the data behind
cairo's back.
Also use CAIRO_FORMAT_ARGB32 rather then CAIRO_FORMAT_RGB24 for the
surface to be consistent with the rest of the code.
https://bugzilla.gnome.org/show_bug.cgi?id=691715
Since we also support passing a basename now, clients might be
interested in knowing the path used to save the file.
Add an out argument to the interface for that.
https://bugzilla.gnome.org/show_bug.cgi?id=688004
If a non-absolute path is passed to the screenshot methods, treat it as
a basename for the output image, and automatically try to save it in
$XDG_PICTURES_DIR, falling back to $HOME if it doesn't exist.
https://bugzilla.gnome.org/show_bug.cgi?id=688004
The screen grabber was a workaround for an extremely slow path in Mesa
when reading back pixel data from the frame buffer. It was using pixel
buffer objects by directly calling into GL to hit a fast blit path in
Intel's driver. This should no longer be necessary with the latest
Mesa because the normal read pixels path now has a fast path to just
memcpy the data. Using PBOs in that case just adds an extra
indirection because the data is read into an intermediate buffer and
then copied back out again.
We want to be able to remove the dependency on linking against libGL
directly from Gnome Shell because that will not work if Cogl is
actually using GLES. Also libGL includes GLX which means gnome-shell
ends up with a hard dependency on Xlib which hinders the goal of
getting Gnome Shell to be a Wayland compositor.
https://bugs.freedesktop.org/show_bug.cgi?id=46631https://bugzilla.gnome.org/show_bug.cgi?id=685915
We've been dangling on the edge of unsafety, unnoticed, for a little while
about the reference count safety of ShellScreenshot. GJS owns the entire
reference count, so as soon as it goes out of scope it could die, causing
GJS to try and fetch the corresponding wrapper object for a stale pointer.
We haven't seen any crashes because of luck -- SpiderMonkey tries to group
together deallocations to limit GC pauses, and there isn't really a lot
of GC pressure in the duration that a screenshot happens, so we tend to
be mostly stable. But in the case that you create a lot of objects while
a screenshot is going on, by hammering the "Print Screen" button, for
example, you can destroy the GObject before the callback finishes.
https://bugzilla.gnome.org/show_bug.cgi?id=672775
