Now that all Cairo contexts are ported to managing cairo surfaces
themselves, the old fallback code that didi the managing is no longer
needed.
Also clarify the behavior of gdk_cairo_context_cairo_create() wrt the
vfunc by doing the early exit and the clipping outside of it.
* Remove DC refcounting (we trust GDK to always do
begin_frame/end_frame calls in pairs)
* Now that there's no GDK-provided double-buffer up the stack,
double-buffering is implemented here
(though it's disabled by default - in my tests it didn't provide
any visual improvements, but did decrease performance).
* For some reason delaying window resizes until the point where
we need to blit the double-buffer into the window leads
to visual glitches, so doulbe-buffered windows are resized
in begin_frame, same as non-double-buffered ones.
* New code to clear the paint region, for all drawing modes.
Hopefully, it isn't duplicated anywhere up the stack.
* GL has its own context now, so remove any GL-related comments.
* Layered windows are still used (because cairo actually works
better with them)
* A bit more code re-use for layered windows
* Some functions that were local to gdksurface-win32.c are made
usable for the whole backend
* Drag-indicator drawing is temporarily commented out to match
a similar change in X11 backend
We used to pass 2 regions to GdkDrawCotnext.end_frame() but code was
confusing what they meant. So we now don't do that anymore and only pass
the region that matters: The frame region.
This makes the previous gdk_draw_context_is_drawing() function public
under a new name.
I decided against the old name because we use the term "frame" for a
drawing operation, so I wanted to have this boolean flag reuse the term.
As they require a draw context and the draw context is already bound to
the surface, it makes much more sense and reduces abiguity by moving
these APIs to the draw context.
As a side effect, we simplify GdkSurface APIs to a point where
GdkSurface now does not concern itself with drawing anymore at all,
apart from being the object that creates draw contexts.
Also, split it into its own file - which was the original reason for
looking at this code, the rewrite was an unintentional side effect.
This changes the context to create surfaces on demand.
So whenever the compositor holds onto a surface while GDK wants to
render, it just creates a new surface. If the compositor releases
surfaces, we will retain one for the next frame to be rendered, but free
all extra ones.
This way, we should get to a stage where we have exactly as many
surfaces as needed and never allocate/free any.
Also, don't implement SurfaceClass.ref_cairo_surface() anymore. This
means calls to it will crash now. But as they only happen in the generic
GdkCairoContext implementation, we shouldn't be affected by that.
Plus, once all backends have been ported, that call is going away
anyway.
And make the GdkCairoContext as abstract.
The idea of this and thje following commits is to get rid of all
Cairo code in gdksurface.c (and $backend/gdksurface-$backend.c)
by moving that code into the Cairo context files.
In particular, the GdkSurfaceClass.begin_frame/end_frame()
functions (which are currently exclusively used by the Cairo code
should end up being moved to GdkDrawContextClass.begin/end_frame().
This has multiple benefits:
1. It unifies code between the different drawing contexts.
GL lives in GLContext, Vulkan in VulkanContext and Cairo in
CairoContext. In turn, this makes it way easier to reason about
what's going on in surface-specific code. Currently pretty much
all backends do things wrong when they want to sync to drawing
or to the frame clock.
2. It makes the API of GdkSurface smaller. No drawing code (apart
from creating the contexts) needs to remain.
3. It confines Cairo to the Drawcontext, thereby making it way
more obvious when backends are still using it in situations
where it may now conflict with OpenGL (like when doing the dnd
failed animation or in the APIs that I'm removing in this
branch).
4. We have 2 very different types of Cairo contexts: The X/win32
model, where we have a natively supported Cairo backend but do
double buffering ourselves and use similar surfaces and the
Wayland/Broadway model where we use image surfaces without any
Cairo backend support and have to submit the buffers manually.
By not sharing code between those 2 versions, we can make the
actual code way smaller. We also get around the need to create
1x1 image surfaces in the Wayland backend where we pretend
there's a native Cairo surface.
This does nothing but disallow passing NULL to gdk_surface_begin_paint()
and instead require this context.
The ultimate goal is to split out Cairo drawing into its own source file
so it doesn't clutter up the generic rendering path.
The shortcuts inhibitors hash table is created when we create a
GdkWaylandWindow implementation for a GdkWindow, and it's destroyed once
we finalize the instance. The fake "root" window we create for the
Wayland display does not have a backing native window, so the shortcuts
inhibitors hash table is set to NULL; this causes a critical error
message when calling g_hash_table_destroy() on it. The finalization of
the root window happens when we close a display connection.
We should use g_clear_pointer(), instead, as it's NULL safe.
Without this change, the displayclose test fails, as all warnings are
considered fatal.
We can't freeze the frame clock on commit, but only after-paint,
otherwise the frameclock will resume in the paint stage.
So freeze the frame clock at the end of the frame if we are waiting for
a frame callback.
Note; The diff is only lage because of indentation changes due to
avoiding early returns in favor of a branch.
Instead of going through an ancillary script to strip away the
`WL_EXPORT` annotation from the generated code, we should bump up the
required version of Wayland, and use the `private-code` argument for
wayland-scanner, which does the right thing for us.
* Previous commit had misleading info. The code was
added to begin_paint() instead of end_paint(). Though
that did not affect its performance in any visible way.
* Company advised to move the code to an "after_paint" signal
handler, so that it works on all renderers, not just Cairo.
This change caused high fluctuation in FPS values in fishbowl
when it is put in a situation where it cannot achieve 60fps
(such as using Cairo renderer at ultra-high resolution).
This seems to be deliberate and not a bug.
There is no easily apparent way of being notified when frame updates
happene exactly, so we just query frame info at the end of each paint.
If we query too often (faster than DWM refresh rate), we just get
the same values twice in a row, but that is, hopefully, highly unlikely.
When asked for a nonexistent (positive) monitor number,
gdk_x11_display_get_monitor would (at best) return an uninitialized pointer,
instead of returning NULL.
That way, we can store the right region there: The actual painted area
instead of the exposed area (which is way too small).
Also, the GL context is the only user of this data, so storing it there
seems way smarter.
This error message is printed into the journal if a GTK app can't
connect to eithre Wayland or X11. Make it at least mention who is not
capable of connecting to a server.
Unrelated, we might want to improve our error reporting when a GTK app
can't start, so that debugging issues with system startup / login get
easier to resolve.
