Joonas spotted that the breakage with the curve bounds was the result of
initialising the spline using the original move to point and not the
current point.
Fixes: Bug 19256 Gnome Foot in gnome-games rendered incorrectly
(https://bugs.freedesktop.org/show_bug.cgi?id=19256)
Declares _cairo_quartz_scaled_font_backend ahead of time and makes it static.
Also, removes the 'static' from the _cairo_quartz_font_backend definition.
If a matrix was something like [0 .000001 0, .000001 0 0] the old code would
assume that xx and yy were greater than 0 and turn the nearly degenerate matrix
into an actual degenerate one. This caused things to blow up later on. Now we
check that our nearly rectangular matrices are not nearly degenerate, and let
the nearly degenerate ones fall through to the non-rectangular path.
Note: I'm not sure why NEARLY_ZERO(d) is fabs(d) < 1/65536 instead of some
other value. Hopefully, it's a useful definition.
This problem was found by a test case attached to:
https://bugzilla.mozilla.org/show_bug.cgi?id=467423
Based on feedback from Jeff Muizelaar, there is a case for a very quick
and dirty extents approximation based solely on the curve control points
(for example when computing the clip intersect rectangle of a path) and
by moving the stroke extension into a core function we can clean up the
interface for all users, and centralise the logic of approximating the
stroke extents.
When analysing the stroke extents, we need the original fixed-point
extents so that we do not incur an OBO when we round-to-integer a second
time. We also need a more accurate estimate than simply using the control
points of the curve, so pass in tolerance and decompose until someone
discovers a cheaper algorithm to determine the precise aligned bounding
box of a bezier curve.
If we are dithering on the Xlib backend we can not simply repaint the
surface used for a solid pattern and must recreate it from scratch.
However, for ordinary XRender usage we do not want to have to pay that
price - so query the backend to see if we can reuse the surface.
