PDF Files with Type 1 fonts fail to open in any version of
ghostscript prior to 8.54. The problem is the hex encoding of the
encrypted portion of the font. The PDF reference says this should
only be in binary.
1. Remove all the alarm/signal code, which just isn't doing what we want for some reason.
Instead, for now we'll simply run for a fixed number of iterations, (perhaps we
can tune that per test later).
2. Before computing mean and stdandard deviation of runs, sort them all and discard the
top and bottom 20% of the values.
Now the standard deviation for the paint test is generally 2% or less.
The interface of the various buffer/image_diff functions is improved to
provide the maximum pixel difference in addition to the number of pixels
that differ. This value can then be used to compare against a per-backend
tolerance.
Currently I've set the SVG backend's tolerance to 1 to handle some issues
we're currently seeing of single-bit differences on different systems, (but
we're not exactly sure why yet).
Also I improved the image_diff routines to properly report a status value
on failure rather than the bogus value of -1 for pixels_changed.
Basically, it's evil to write a loop like:
while ((c -= 4) > 0) {
...
}
for one reason that doesn't work if c is unsigned. And when c is signed, if
for some reason c is about -MAXINT, then it will overflow and not work as
expected.
It's much safer (and more gcc warning friendly) to rewrite it as:
unsigned int c;
while (c >= 4) {
...
c -= 4;
}
Behdad chased this bug down when looking into bug #7593. This
bug is what finally motivated us to figure out how to get -Wextra
(for the "always true" comparisons of unsigned variables against
negative values).
We'd been wanting some of the warnings in -Wextra for a long time,
but we had failed in tryingto squelch some of the undesired warnings.
We finally figured out how to do this correctly by simply ordering
the warnings correctly.
The documentation for GetGlyphOutline() states that outline returned is grid
fitted and if an application requires an unmodified outline it can request an
outline for a font whose size is equal to the font's em unit.
This seems to suggest that the solution to this bug would be to obtain the
unmodified outline data and scale it to the required size.
https://bugs.freedesktop.org/show_bug.cgi?id=7603
