This program displays a linear gradient from blue to yellow. Due to
limited precision in pixman-gradient-walker.c, it currently has some
ugly artefacts that gives it a 'brushed metal' appearance.
V2: Update .gitignore
GdkPixbufs are not premultiplied, so when using them to display pixman
images, there is some unecessary conversions going on: First the image
is converted to non-premultiplied, and then GdkPixbuf premultiplies
before sending the result to the X server. These conversions may cause
the displayed image to not be exactly identical to the original.
This patch just uses a cairo image surface instead, which avoids these
conversions.
Also make the comment about sRGB a little more concise.
For large upscalings the level of subsampling for the filter has a
quite visible effect, so make it settable in the UI so that people can
experiment with various values.
Add two new gradient columns, one where the start circle is has radius
0 and one where the end circle has radius 0. All the new gradients
except for one are rendered with a bright dot in the middle. In most
but not all cases this is incorrect.
Cc: ranma42@gmail.com
This new test is derived from radial-test.c and displays conical
gradients at various angles.
It also demonstrates how PIXMAN_REPEAT_NORMAL is supposed to work when
used with a gradient specification where the first stop is not a 0.0:
In this case the gradient is supposed to have a smooth transition from
the last stop back to the first stop with no sharp transitions. It
also shows that the repeat mode is not ignored for conical gradients
as one might be tempted to think.
The zone plate image is a useful test case for image scalers because
it contains all representable frequencies, so any imperfection in
resampling filters will show up as Moire patterns.
This version is symmetric around the midpoint of the image, so since
rotating it is supposed to be a noop, it can also be used to verify
that the resampling filters don't shift the image.
V2: Run the file through OptiPNG to cut the size in half, as suggested
by Siarhei.
This program allows interactively scaling and rotating images with
using various filters and repeat modes. It uses
pixman_filter_create_separate_convolution() to generate the filters.
This test runs the new floating point combiners on random input with
divide-by-zero exceptions turned on.
With the floating point combiners the only thing we guarantee is that
divide-by-zero exceptions are not generated, so change
enable_fp_exceptions() to only enable those, and rename accordingly.
This makes show_image() deal with more formats than just a8r8g8b8, in
particular, a8r8g8b8_sRGB can now be handled.
Images that are passed to show_image with a format of a8r8g8b8_sRGB
are displayed without modification under the assumption that the
monitor is approximately sRGB.
Images with a format of a8r8g8b8 are also displayed without
modification since many other users of show_image() have been
generating essentially sRGB data with this format. Other formats are
also assumed to be gamma compressed; these are converted to a8r8g8b8
before being displayed.
With these changes, srgb-test.c doesn't need to do its own conversion
anymore.
Simple sRGB color blender test can be used to determine if the sRGB processing
works as expected. It blends alpha ramps of purple and green together such that
at midpoint of image, 50 % blend of both is realized. At that point, sRGB-aware
processing yields a result close to #bbb rather than #888, which is the linear
light blending result.
The demo also contains the sample computation for sRGB premultiplied alpha.
This program can compute the projective transformation that transforms
one quadrilateral into another. The code is basically maxima[1] output
translated into C.
[1] http://maxima.sourceforge.net/
This patch modifies demos/gradient-test to display a bug in gradients
with a repeat mode of NONE. With the current gradient code, the left
side will be a solid red (actually an extremely long fade from solid
red to transparent) instead of a sharp transition from red to green.
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 separates the test suite from the random gtk+ using test
programs. "demos" is somewhat misleading because the programs there
are not particularly exciting (with the possible exception of
composite-test which shows off all the compositing operators).
