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December 1994

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Archive maintained by AWare Systems

1994.12.01 08:13 "question", by Ted Lin

Hi,

I have generated a TIFF image (Version 42) from a raw binary image that is 4
bits per pixel.  What I have done is packing two 4-bit pixel into one 8-bit
byte, all bytes contiguous.  For the TIFF file, I have declared
BitsPerSample=4, Compression=1, PhotomentricInterpretation=3,
SamplesPerPixel=1, a colormap of 16 levels for each of the RGB color, and
other required fields for width, height, etc.

Using a standard TIFF reader ("image tool" on Sun Sparc 20), the image has
the specified width and height but the real image looks as if it has been
squashed horizontally into half of the original size and been placed on the
left half of the output image where the right half is filled up with black
pixels.  Would you happen to know what was going on.  The 8 bits per pixel
image looks the same as the original image but the 4 bits per pixel image
doesn't look too good.

Thanks and have a nice day.

					Ted