Nearest neighbor resize algorithm relies on undefined behavior

[tobihan]

The test TEST(ResizeImage, NearestNeighborInterp) fails on Debian on i386 architectures [1].

The image gets resized to this:

000011100
000011100
000011100
111111111
111111111
111111111
000011100
000011100
000011100

instead of the expected

000111000
000111000
000111000
111111111
111111111
111111111
000111000
000111000
000111000

I suspect that's because of the undefined result of floor(3./3.) that is called in resize_image(). Maybe you should add some small shifts to make this well-defined.

Best,
Tobias

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=765291

[dacap]

Hi @tobihan, could you please check if 97d42de fixes this issue.

[tobihan]

Hi. Yes, that fixes it, thanks!

On 07/25/2016 04:17 PM, David Capello wrote:

Hi @tobihan https://github.com/tobihan, could you please check if
97d42de
97d42de
fixes this issue.

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