Any data that is later fed to graphene must be
allocated with proper alignment, if graphene
uses SSE2 or GCC vector instructions.
This adds custom array code (a streamlined copy
of GArray with all unnecessary bells and whistles removed),
which is then used for the state_stack instead of GArray.
There's also a runtime check for the size of GtkSnapshotState
itself being a multiple of 16. If that is not so, any array
elements past the 0th element will lose alignment.
There are probably struct attributes that can
make GtkSnapshotState always have size that is a multiple
of 16, but we'll burn that bridge if we cross it.
The check survived from GTK2 when that function could still return
GdkPixmap and GdkFont objects and was accompanied by this comment:
/* We may receive events such as NoExpose/GraphicsExpose
* and ShmCompletion for pixmaps
*/
and gtk_image_set_can_shrink().
Images are meant to always be icon-sized, they can never shrink below
that.
And images are icons, so they are meant to be square. If they are
not, we pretned that's by accident and keep aspect ratio.
This commit introduces GtkPicture, which is supposed to complement
GtkImage.
GtkImage will be adapted to always display an icon, while
GtkPicture displays regular imagery.
Instead declare a priv local. We should do this even if we don't remove
the priv pointer from GtkWidget entirely, just to stay consistent with
new code we introduce.
The code is mostly stolen from graphene.
Allocators support any alignment, but their implementation
only calls system aligned allocator functions if malloc()
is not aligned to 16-byte boundaries. If it is aligned,
the implementation just calls malloc() regardless of which
alignment is requested by the caller.
This can be fixed by saving the result of meson malloc()
alignment check and adding a few conditions to the implementation,
but right now GSK and GTK only need 16-byte alignment either way.
* A bunch of new variables for config.h.meson
* A check for aligned allocation being necessary at all
(graphene must use GCC vector instructions or SSE2)
* A check for C malloc() being aligned at 16-byte boundaries
* A check for a few special aligned allocator functions being
present and not being built-ins (posix_memalign is a builtin
in GCC, even on platforms where there is no posix_memalign
system function)
* Added -mstackrealign flag on Windows, since otherwise
stack variables may become unaligned when the stack briefly
passes through OS code (such as in various callbacks and
handlers)
Otherwise, requesting a min size in em where the equivalent in px had a
fractional part would lead to the widget getting allocated 1 too few px.
You could see this in the CSS property vs. allocation in the Inspector.
Note that margin/border/padding are left alone: the rationale is that we
do as browsers do, and Benjamin said we already do that for those,
whereas his tests on min-(width|height) showed otherwise. My subsequent
analysis indicated it to be far less clear-cut than that, but he remains
unconvinced that we should ceil() all the things! So just do these ones.
https://gitlab.gnome.org/GNOME/gtk/issues/1088
This is the API used by GtkMenu to properly position menus on the screen
without requiring GTK to query the menu window's position or the work
area of where the window is positioned. It makes it possible to position
popup windows properly when using Wayland.
Make this API available to external users so custom popup windows can be
positioned properly as well.
Related: https://gitlab.gnome.org/GNOME/gtk/issues/997
