2011.04.23 09:41 "Re: [Tiff] [GM-help] PDF version", by Hunter1972
> You can adjust the GraphicsMagick output by adding a gamma adjustment > step. Compare the dramatic difference between these two commands:
> gm convert src.jpg -gamma 0.45 -monochrome -colors 2 gamma-0.45.tiff
> gm convert src.jpg -gamma 2.6 -monochrome -colors 2 gamma-2.6.tiff
Yes, Bob, I checked it, the difference is seen by naked eye, thank you!
Then I decided to create a colored TIFF file with JPEG compression. Gm utility ("convert -compress jpeg c:\3.jpg c:\45.tif") is finished with 1 not creating the file.
My own utility raises an exception with the message: "ImageLibExe: JPEG compression support is not configured. (c:\59.tif) reported by ..\..\coders\tiff.c:621 (TIFFErrors)"
Under debugger I found that the error is caused in tiff.c (line 4644, TIFFWriteScanline).
I had the similar problem with bmp2tif.c module from libtiff and there it was resolved by setting TIFFTAG_ROWSPERSTRIP to 8 or 16 (in command line "-r 8") Here as I see TIFFTAG_ROWSPERSTRIP is set to 16 so the problem not in it. What to do?