libvips issue #703

Test case for libvips/libvips#703.

The example images for the various EXIF orientation flags are taken from this repo:
https://github.com/recurser/exif-orientation-examples

Build

git clone https://github.com/kleisauke/vips-issue-703.git
cd vips-issue-703
mkdir build && cd build
cmake .. \
  -DCMAKE_BUILD_TYPE=Release
make

Or if you prefer to build without CMake:

git clone https://github.com/kleisauke/vips-issue-703.git
cd vips-issue-703
g++ -g -Wall test-anim.cpp `pkg-config vips-cpp --cflags --libs` -o test-anim
g++ -g -Wall test-single.cpp `pkg-config vips-cpp --cflags --libs` -o test-single

Run

G_MESSAGES_DEBUG=all ./test-single

# Generate an animated WebP image from the output of `./test-single`
./test-anim

# https://github.com/libvips/pyvips/issues/148
VIPS_CONCURRENCY=1 VIPS_NOVECTOR=1 python3 test-resize.py input/radial.rgb.png

See output/ directory.

Debugging notes

Notes

Only reduce an image vertically (using only reducev):

VIPS_NOVECTOR=1 vips reducev input/Landscape_1.jpg output-patch/lanczos3/Landscape_1.jpg[strip,Q=85] 5.624992969 --kernel lanczos3 --centre

VIPS_NOVECTOR=1 vips reducev input/Landscape_2.jpg temp.v 5.624992969 --kernel lanczos3 --centre
vips flip temp.v output-patch/lanczos3/Landscape_2.jpg[strip,Q=85] horizontal

VIPS_NOVECTOR=1 vips reducev input/Landscape_3.jpg temp.v 5.624992969 --kernel lanczos3 --centre
vips rot temp.v output-patch/lanczos3/Landscape_3.jpg[strip,Q=85] d180

VIPS_NOVECTOR=1 vips reducev input/Landscape_4.jpg temp.v 5.624992969 --kernel lanczos3 --centre
vips rot temp.v temp2.v d180
vips flip temp2.v output-patch/lanczos3/Landscape_4.jpg[strip,Q=85] horizontal

vips rot input/Landscape_5.jpg temp.v d270
VIPS_NOVECTOR=1 vips reducev temp.v temp2.v 5.624992969 --kernel lanczos3 --centre
vips flip temp2.v output-patch/lanczos3/Landscape_5.jpg[strip,Q=85] vertical

vips rot input/Landscape_6.jpg temp.v d90
VIPS_NOVECTOR=1 vips reducev temp.v output-patch/lanczos3/Landscape_6.jpg[strip,Q=85] 5.624992969 --kernel lanczos3 --centre

vips rot input/Landscape_7.jpg temp.v d90
VIPS_NOVECTOR=1 vips reducev temp.v temp2.v 5.624992969 --kernel lanczos3 --centre
vips flip temp2.v output-patch/lanczos3/Landscape_7.jpg[strip,Q=85] vertical

vips rot input/Landscape_8.jpg temp.v d270
VIPS_NOVECTOR=1 vips reducev temp.v output-patch/lanczos3/Landscape_8.jpg[strip,Q=85] 5.624992969 --kernel lanczos3 --centre

rm {temp,temp2}.v

Only reduce an image horizontally (using only reduceh):

vips reduceh input/Landscape_1.jpg output-patch/lanczos3/Landscape_1.jpg[strip,Q=85] 5.624992969 --kernel lanczos3 --centre

vips reduceh input/Landscape_2.jpg temp.v 5.624992969 --kernel lanczos3 --centre
vips flip temp.v output-patch/lanczos3/Landscape_2.jpg[strip,Q=85] horizontal

vips reduceh input/Landscape_3.jpg temp.v 5.624992969 --kernel lanczos3 --centre
vips rot temp.v output-patch/lanczos3/Landscape_3.jpg[strip,Q=85] d180

vips reduceh input/Landscape_4.jpg temp.v 5.624992969 --kernel lanczos3 --centre
vips rot temp.v temp2.v d180
vips flip temp2.v output-patch/lanczos3/Landscape_4.jpg[strip,Q=85] horizontal

vips rot input/Landscape_5.jpg temp.v d270
vips reduceh temp.v temp2.v 5.624992969 --kernel lanczos3 --centre
vips flip temp2.v output-patch/lanczos3/Landscape_5.jpg[strip,Q=85] vertical

vips rot input/Landscape_6.jpg temp.v d90
vips reduceh temp.v output-patch/lanczos3/Landscape_6.jpg[strip,Q=85] 5.624992969 --kernel lanczos3 --centre

vips rot input/Landscape_7.jpg temp.v d90
vips reduceh temp.v temp2.v 5.624992969 --kernel lanczos3 --centre
vips flip temp2.v output-patch/lanczos3/Landscape_7.jpg[strip,Q=85] vertical

vips rot input/Landscape_8.jpg temp.v d270
vips reduceh temp.v output-patch/lanczos3/Landscape_8.jpg[strip,Q=85] 5.624992969 --kernel lanczos3 --centre

rm {temp,temp2}.v

Only shrink an image vertically (using only shrinkv):

vips shrinkv input/Landscape_1.jpg output-patch/lanczos3/Landscape_1.jpg[strip,Q=85] 3

vips shrinkv input/Landscape_2.jpg temp.v 3
vips flip temp.v output-patch/lanczos3/Landscape_2.jpg[strip,Q=85] horizontal

vips shrinkv input/Landscape_3.jpg temp.v 3
vips rot temp.v output-patch/lanczos3/Landscape_3.jpg[strip,Q=85] d180

vips shrinkv input/Landscape_4.jpg temp.v 3
vips rot temp.v temp2.v d180
vips flip temp2.v output-patch/lanczos3/Landscape_4.jpg[strip,Q=85] horizontal

vips rot input/Landscape_5.jpg temp.v d270
vips shrinkv temp.v temp2.v 3
vips flip temp2.v output-patch/lanczos3/Landscape_5.jpg[strip,Q=85] vertical

vips rot input/Landscape_6.jpg temp.v d90
vips shrinkv temp.v output-patch/lanczos3/Landscape_6.jpg[strip,Q=85] 3

vips rot input/Landscape_7.jpg temp.v d90
vips shrinkv temp.v temp2.v 3
vips flip temp2.v output-patch/lanczos3/Landscape_7.jpg[strip,Q=85] vertical

vips rot input/Landscape_8.jpg temp.v d270
vips shrinkv temp.v output-patch/lanczos3/Landscape_8.jpg[strip,Q=85] 3

rm {temp,temp2}.v

Only shrink an image horizontally (using only shrinkh):

vips shrinkh input/Landscape_1.jpg output-patch/lanczos3/Landscape_1.jpg[strip,Q=85] 3

vips shrinkh input/Landscape_2.jpg temp.v 3
vips flip temp.v output-patch/lanczos3/Landscape_2.jpg[strip,Q=85] horizontal

vips shrinkh input/Landscape_3.jpg temp.v 3
vips rot temp.v output-patch/lanczos3/Landscape_3.jpg[strip,Q=85] d180

vips shrinkh input/Landscape_4.jpg temp.v 3
vips rot temp.v temp2.v d180
vips flip temp2.v output-patch/lanczos3/Landscape_4.jpg[strip,Q=85] horizontal

vips rot input/Landscape_5.jpg temp.v d270
vips shrinkh temp.v temp2.v 3
vips flip temp2.v output-patch/lanczos3/Landscape_5.jpg[strip,Q=85] vertical

vips rot input/Landscape_6.jpg temp.v d90
vips shrinkh temp.v output-patch/lanczos3/Landscape_6.jpg[strip,Q=85] 3

vips rot input/Landscape_7.jpg temp.v d90
vips shrinkh temp.v temp2.v 3
vips flip temp2.v output-patch/lanczos3/Landscape_7.jpg[strip,Q=85] vertical

vips rot input/Landscape_8.jpg temp.v d270
vips shrinkh temp.v output-patch/lanczos3/Landscape_8.jpg[strip,Q=85] 3

rm {temp,temp2}.v

Output

Thumbnail

Produces pixel shifts

Shrink an image vertically

Produces pixel shifts on the vertical axis

Shrink an image horizontally

Produces pixel shifts on the horizontal axis

Upscale

Upscale does not appear to produce pixel shifts

Output after pull request

See libvips/libvips#1592.

Thumbnail

Does not produce pixel shifts

Shrink an image vertically

Pixel shifts are gone

Shrink an image horizontally

Pixel shifts are gone