This adds save/restore calls to the clear-to-transparent call in
the pixel cache, to avoid changing the default color of the
cairo_t. It also removes a call set_operator call that is no longer
necessary (it was trying to manually restore the state).
https://bugzilla.gnome.org/show_bug.cgi?id=721480
If a queue_redraw() (invalidating a region, or the whole widget) was
called from the draw() call, it could get ignored if surface_dirty
existed, as it would then be updated, but destroyed right at the end of
the _gtk_pixel_cache_repaint(), leading the next call to
_gtk_pixel_cache_draw() have its call to repaint() be a no-op
(since there's no surface_dirty) and then simply draw from (non
updated) surface.
Signed-off-by: Olivier Brunel <jjk@jjacky.com>
https://bugzilla.gnome.org/show_bug.cgi?id=711545
If the new requested surface size is enough larger than the previous
one (but the old is still larger than the absolute minimum),
reallocate it anyway.
This fixes an issue where the text view initially requested a really
small extra size which was then increased but that didn't "take".
GtkPixelCache is a helper utility that lets you implement
faster scrolling of a viewport of a canvas by using an
offscreen pixmap cache.
You call _gtk_pixel_cache_draw with a callback function that
does the drawing, and additionally you specify the size and the
position of the viewport in the widget, and the position and size
of the canvas wrt the viewport. The callback will be called to
draw on an offscreen surface, and the surface will be drawn
on the window. The next time you do the same, any already drawn
pieces of the surface are re-used from the offscreen and need
not be rendered again.
If things inside the canvas change you need to call
_gtk_pixel_cache_invalidate to tell the cache about this.
Some other details:
* The offscreen surface is generally a bit larger than
the viewport, so scrolling a small amount can often
be done without redrawing children.
* If the canvas is not larger than the viewport no
offscreen surface is used.
GtkPixelCache: Make sure we always copy using SOURCE
We were using OVER for the first copy (from source to group surface.
GtkPixelCache: Fix x/y typos
GtkPixelCache: Allow NULL for invalidate region
gtkpixelcache: Use CONTENT_COLOR for solid bg windows
