During MT cairo testing we get the error "libpng: Read Error" which is
emitted should the fread return fewer bytes than asked. However, this is
not necessarily an error, so double-check the ferror() status before
raising a png_error().
Toolkits like GTK+ almost always set a simple rectangular clip mask before
any cairo operation, so avoid the allocation for this simple case by
embedding a small number of XRectangles into the surface structure.
_cairo_surface_create_similar_solid() creates a fresh pattern to wrap
color, however sometimes the caller already has that pattern available.
In those circumstances we can pass the pattern as well as the color and
avoid the extra allocation.
For opaque surfaces the backends may use simpler code paths - for
example, the xlib backend may be able to use the Core protocol rather
than Render. So we only generate a surface with an alpha component if
the color is not opaque.
The so-attributed-to-X-server bug was that cairo maps the drawing
region to the pattern space, rounds the box, and uploads only that
part of the source surface to the X server. Well, this only works for
NEAREST filter as any more sophisticated filter needs to sneak a peek
at the neighboring pixels around the edges too.
The right fix involves taking into account the filter used, and the
pattern matrix, but for most cases, a single pixel should be enough.
Not sure about scaling down...
Anyway, this is just a workaround to get 1.4.4 out of the door. I'll
commit a proper fix soon.
Due to the interaction between multiple threads showing glyphs and
asynchronous CloseDisplays, it is possible for a font to maintain a
cairo_xlib_screen_info_t beyond the CloseDisplay. The simple solution
is to add a reference count in order to track the lifetime of the
cairo_xlib_screen_info_t correctly.
This new feature isn't appropriate for a minor cairo release,
(we're between 1.4.2 and 1.4.4 right now), but will make a
lot of sense during 1.5.
The code being reverted here was originally added with the
following commit:
46eab95698
but this change reverts only the public-facing parts of it.
In order to avoid recursive dead-locks where whilst one thread holds the
scaled font lock and is waiting on the XLockDisplay() another thread catches
the CloseDisplay and then tries to acquire the scaled font lock, we drop
the list mutex whilst processing the callbacks.
Do not initialize font options when setting up the
cairo_xlib_screen_info_t corresponding to the display itself and not
associated with any screen. This avoids a potential NULL dereferences.
(Fixes https://bugs.freedesktop.org/show_bug.cgi?id=10517)
