In order to correctly report the error back to the user during the
creation of a scaled font, we need to support a nil object per error.
Instead of statically allocating all possible errors, lazily allocate
the nil object the first time we need to report a particular error.
This fixes the misreporting of an INVALID_MATRIX or NULL_POINTER that
are common user errors during the construction of a scaled font.
Partial revert of commit 0086db893c.
This is a follow to the earlier commit that allowed creation of scaled
fonts using a NULL font options (by interpreting the NULL as meaning
use the default options) to reflect the comments made by Behdad
(http://lists.cairographics.org/archives/cairo/2008-January/012714.html).
The intent is that the public font options getter/setter API has similar
defensive behaviour to that of the core objects - i.e. do not overwrite
the nil object and if the object is in error then return the default
value. For the indirect use of a NULL/nil font options (e.g. creation of
scaled fonts), then an error should be returned rather than crashing.
Inspired by bug 7362 (painting a glitz surface onto an xlib surface
crashes cairo) and the lack of coverage for
_cairo_paginated_surface_acquire_source_image(), these tests attempt
to use each backend as a source surface for all the other backends.
For example, this checks that one can construct a PS file ready for
printing and then copy that surface to an image/xlib for previewing.
This seems redundant with the recent testing of all test cases
against similar surfaces. Plus, it hasn't had a reference image
anyway which was causing problems with the recent extra checks
for missing reference images.
This test has been "failing" ever since we had native
replay of metasurfaces to pdf. But looking at the results,
they are actually superior to the image-backend reference
images.
Thanks for Behdad for the suggested name improvement. Also, make
it more clear that the stride passed to cairo_image_surface_create_for_data
should come from calling cairo_format_stride_for_width with the
same width.
Document this function as a required call to get the correct
stride value before calling cairo_image_surface_create_for_data.
This means that previously-failing calls with non-multiple-of-4
stride values are now documented as errors. Also, we now have
the possibility of moving to more stringent alignment constraints,
(one can imagine doing 64-bit or 128-bit boundaries for example).
This is now failing as we compute NAN font metrics for bitmap-only fonts under
disabled metrics hinting. A very infamous bug excercised with PangoCairo's PDF
output.
It's a common idiom to stroke degenerate sub-paths made with
cairo_move_to(x,y);cairo_rel_line_to(0,0) to draw dots. Test
that we get the desired extents from cairo_fill_extents,
cairo_stroke_extents, and cairo_path_extents for these cases.
Also document that the cairo_path_extents result is equivalent
to the limit of stroking with CAIRO_LINE_CAP_ROUND, (so that
these "dot" points are included), as the line width
approaches 0.0 .
