Created attachment 6442 [details] screenshot.png Converting the file B-12-3077-1831-7-001.pdf (which can be found in tests_private/compare_files) with r11306 to a 1 bit b/w format (e.g. pbmraw) results in a very dark background; r11305 and earlier versions result in a white background, as does converting to a continuous tone format (e.g. pgmraw). The command line I'm using for testing: bin/gs -sDEVICE=pbmraw -o test.pbm ./B-12-3077-1831-7-001.pdf
Created attachment 6446 [details] AR9_B-12-3077-1831-7-001.tiff Output from Adobe Acrobat 9 for reference (72 dpi tiffg4)
Tracked this down in the icc image interpolation code. Output of interpolation is coming out scaled between 0 and 0x7fff and I am expecting it to be 0 and 0xffff hence the darker output. Should have this resolved shortly.
Found that the special image downsample scaling filters for dithered devices has baked into it scaling to and from frac. It should be paying attention to the range scaling values in stream_image_scale_state_common. This should be easy to fix.
Fixed with rev 11505