A check is needed that the creation of the temporary image in
pixman_composite_trapezoids() succeeds.
Fixes crash in stress-test -s 0x313c on my system.
stress-test -s 0x17ee crashes because pixman_composite_trapezoids() is
given a mask_format of PIXMAN_c8, which causes it to create a
temporary image with that format but without a palette. This causes
crashes later.
The only mask_format that we actually support are those of TYPE_ALPHA,
so this patch add a return_if_fail() to ensure this.
Similarly, although currently it won't crash if given an invalid
format, alpha-only formats have always been the only thing that made
sense for the pixman_rasterize_edges() functions, so add a
return_if_fail() ensuring that the destination format is of type
PIXMAN_TYPE_ALPHA.
pixman_composite_trapezoids() is supposed to composite across the
entire destination, but it actually only composites across the extent
of the trapezoids. For operators such as ADD or OVER this doesn't
matter since a zero source has no effect on the destination. But for
operators such as SRC or IN, it does matter.
So for such operators where a zero source has an effect, don't clip to
the trap extents.
Add const to pointer arguments when the function doesn't change the
pointed-to data.
Also in add_glyphs() in pixman-glyph.c make 'white' in add_glyphs()
static and const.
Previously, this function would do coordinate calculations in such a
way that (x_dst, y_dst) would only affect the alignment of the source
image, but not of the traps, which would always be considered to be in
absolute destination coordinates. This is unlike the
pixman_image_composite() function which also registers the mask to the
destination.
This patch makes it so that traps are also offset by (x_dst, y_dst).
Also add a comment explaining how this function is supposed to
operate, and update tri-test.c and composite-trap-test.c to deal with
the new semantics.
This allows some more code to be deleted from the X server. The
implementation consists of converting to trapezoids, and is shared
with pixman_composite_triangles().
The Render X extension can draw triangles as well as trapezoids, but
the implementation has always converted them to trapezoids. This patch
moves the X server's triangle conversion code into pixman, where we
can reuse the pixman_composite_trapezoid() code.
This function is an implementation of the X server request
Trapezoids. That request is what the X backend of cairo is using all
the time; by moving it into pixman we can hopefully make it faster.
Removes useless variable declarations. This can only result in more
efficient code, as these variables where sometimes assigned, but
their values were never used.
The rules for trap rasterization is that coordinates are rounded
towards north-west.
The pixman_sample_ceil() function is used to compute the first
(top-most) sample row included in the trap, so when the input
coordinate is already exactly on a sample row, no rounding should take
place.
On the other hand, pixman_sample_floor() is used to compute the final
(bottom-most) sample row, so if the input is precisely on a sample
row, it needs to be rounded down to the previous row.
This commit fixes the rounding computation. The idea of the
computation is like this:
Floor operation that rounds exact matches down: First subtract
pixman_fixed_e to make sure input already on a sample row gets rounded
down. Then find out how many small steps are between the input and the
first fraction. Then add those small steps to the first fraction.
The ceil operation first adds (small_step + pixman_e), then runs a
floor. This ensures that exact matches are not rounded off.
Based on a patch by M Joonas Pihlaja.
- Add underscores to the pixman_image_get_solid(),
pixman_image_is_solid(), and pixman_is_opaque() names.
- A number of formatting fixes
- Move debug code to the end of pixman-private.h
- Collect all prototypes for image methods in one place
