TIFFReadScanline produces different output from TIFFRGBA variants

[jzern]

Versions tested: 4.0.3 & 4.0.6 via x86-64 Linux distros, 3.9.5 (32-bit) & 4.0.6 from source under Linux and 4.0.5 on OS X while double checking the test cases.

TIFFReadScanline() produces what appears to be the correct output. It also agrees with ffmpeg-N-78600-g7ad6a21 and ImageMagick-6.7.7-10 output.

Test cases based on the sample code within the tiff manual attached.

Related bug [1], original report [2].

$ tar -xzf test_case.tar.gz $ cd test_case $ make $ mkdir output $ for t in test_case_rgbaimage test_case_rgbaimage2 test_case_scanline; do \

./$t old_logo.tiff > output/$t.pam; done

$ cmp -b output/test_case_rgbaimage.pam output/test_case_rgbaimage2.pam $ cmp -b output/test_case_rgbaimage.pam output/test_case_scanline.pam output/test_case_rgbaimage.pam output/test_case_scanline.pam differ: byte 68, line 8 is 4 ^{D 17} O

[1] ​https://bugs.chromium.org/p/webp/issues/detail?id=292 [2] ​http://bugzilla.maptools.org/show_bug.cgi?id=2537

[jzern]

test case

[jzern]

image diff

[jzern]

The attached image diff is output from:

$ compare output/test_case_rgbaimage.pam output/test_case_scanline.pam

[Even Rouault]

Closing as it is really a duplicate of ​http://bugzilla.maptools.org/show_bug.cgi?id=2537