This is not really needed. The gl context is totally tied to the
window it is created from by virtue of sharing the context with the
paint context of that window and that context always has the visual
of the window (which we already can get).
Also, all user visible contexts are essentially offscreen contexts, so
a visual doesn't make sense for them. They only use FBOs which have
whatever format that the users sets up.
To properly support multithreaded use we use a global GPrivate
to track the current context. Since we also don't need to track
the current context on the display we move gdk_display_destroy_gl_context
to GdkGLContext::discard.
We used to have a weak ref to the cairo surface and it was keep
alive by the references in the normal windows, but that reference
was removed by d48adf9cee, causing
us to constantly create and destroy the surface.
https://bugzilla.gnome.org/show_bug.cgi?id=738648
We want to create windows with the default visuals such that we then
have the right visual for GLX when we want to create the paint GL
context for the window.
For instance, (in bug 738670) the default rgba visual we picked for the
NVidia driver had an alpha size of 0 which gave us a BadMatch when later
trying to initialize a gl context on it with a alpha FBConfig.
Instead of just picking what the Xserver likes for the default, and just
picking the first rgba visual we now actually call into GLX to pick
an appropriate visual.
The visuals are typically sorted by some sort of "most useful first"
order. And picking the last one is likely to give us the weirdest
matching glx visual.
Commits 314b6abbe8 and eb9223c008 were ignoring
the fact that the code where found is set to 1 was modifying
col - which was an ok thing to do when that part of the code
was still breaking out of the loop, but it is no longer doing
that (since 2003 !). Fix things up by storing the final col
value in a separate variable and using that after the loop.
https://bugzilla.gnome.org/show_bug.cgi?id=738886
Its not really reasonable to handle failures to make_current, it
basically only happens if you pass invalid arguments to it, and
thats not something we trap on similar things on the X drawing side.
If GL is not supported that should be handled by the context creation
failing, and anything going wrong after that is essentially a critical
(or an async X error).
We make user facing gl contexts not attached to a surface if possible,
or attached to dummy surfaces. This means nothing can accidentally
read/write to the toplevel back buffer.
This adds the new type GdkGLContext that wraps an OpenGL context for a
particular native window. It also adds support for the gdk paint
machinery to use OpenGL to draw everything. As soon as anyone creates
a GL context for a native window we create a "paint context" for that
GdkWindow and switch to using GL for painting it.
This commit contains only an implementation for X11 (using GLX).
The way painting works is that all client gl contexts draw into
offscreen buffers rather than directly to the back buffer, and the
way something gets onto the window is by using gdk_cairo_draw_from_gl()
to draw part of that buffer onto the draw cairo context.
As a fallback (if we're doing redirected drawing or some effect like a
cairo_push_group()) we read back the gl buffer into memory and composite
using cairo. This means that GL rendering works in all cases, including
rendering to a PDF. However, this is not particularly fast.
In the *typical* case, where we're drawing directly to the window in
the regular paint loop we hit the fast path. The fast path uses opengl
to draw the buffer to the window back buffer, either by blitting or
texturing. Then we track the region that was drawn, and when the draw
ends we paint the normal cairo surface to the window (using
texture-from-pixmap in the X11 case, or texture from cairo image
otherwise) in the regions where there is no gl painted.
There are some complexities wrt layering of gl and cairo areas though:
* We track via gdk_window_mark_paint_from_clip() whenever gtk is
painting over a region we previously rendered with opengl
(flushed_region). This area (needs_blend_region) is blended
rather than copied at the end of the frame.
* If we're drawing a gl texture with alpha we first copy the current
cairo_surface inside the target region to the back buffer before
we blend over it.
These two operations allow us full stacking of transparent gl and cairo
regions.
Before 5e325c4, the default BitGravity was NorthWestGravity.
When static gravities were removed in 5e325c4, the BitGravity regressed
to the X11 default, Forget. Forget causes giant graphical glitches and
black flashes when resizing, especially in some environments that aren't
synchronized to a paint clock yet, like XWayland.
I'm assuming that the author assumed that the default of BitGravity was
NorthWestGravity, which is the default of WinGravity. Just go ahead and
fix this regression to make resizing look smooth again.
Remove checks for NULL before g_free() and g_clear_object().
Merge check for NULL, freeing of pointer and its setting
to NULL by g_clear_pointer().
https://bugzilla.gnome.org/show_bug.cgi?id=733157
The warning may have had some value at some point, but if
people uninstall large icons just to make the warning go
away, it does more harm than good. So just remove it.
If we have a fullscreen window that covers a monitor, desktop
chrome is not relevant for placing of menus and other popups.
Therefore, return the full monitor geometry instead of the
workarea in this case.
https://bugzilla.gnome.org/show_bug.cgi?id=737251
gdk_x11_display_set_window_scale() affects the interpretation of the
Xft/DPI XSETTING - it is substituted inside GDK with the value of
Gdk/UnscaledDPI xsetting. However, this change is not propagated to
GTK+ and from GTK+ back to gdk_screen_set_resolution() until the
main loop is run.
Fix this by handling the screen resolution directly in gdk/x11.
This requires duplication of code between GDK and GTK+ since we still
have to handle DPI in GTK+ in the case that GdkSettings:gtk-xft-dpi
is set by the application.
https://bugzilla.gnome.org/show_bug.cgi?id=733076
Traditionally, the way painting was done in GTK+ was with the
"expose-event" handler, where you'd use GDK methods to do drawing on
your surface. In GTK+ 2.24, we added cairo support with gdk_cairo_create,
so you could paint your graphics with cairo.
Since then, we've added client-side windows, double buffering, the paint
clock, and various other enhancements, and the modern way to do drawing
is to connect to the "draw" signal on GtkWidget, which hands you a
cairo_t. To do double-buffering, the cairo_t we hand you is actually on
a secret surface, not the actual backing store of the window, and when
the draw handler completes we blit it into the main backing store
atomically.
The code to do this is with the APIs gdk_window_begin_paint_region,
which creates the temporary surface, and gdk_window_end_paint which
blits it back into the backing store. GTK+'s implementation of the
"draw" signal uses these APIs.
We've always sort-of supported people calling gdk_cairo_create
"outside" of a begin_paint / end_paint like old times, but then you're
not getting the benefit of double-buffering, and it's harder for GDK to
optimize.
Additionally, newer backends like Mir and Wayland can't actually support
this model, since they're based on double-buffering and swapping buffers
at various points in time. If we hand you a random cairo_t, we have no
idea when is a good time to swap.
Remove support for this.
This is technically a GDK API break: a warning is added in cases where
gdk_cairo_create is called outside of a paint cycle, and the returned
surface is a dummy that won't ever be composited back onto the main
surface. Testing with complex applications like Ardour didn't produce
any warnings.
