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October 2005
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2005.10.26 21:38 "Re: checking test images", by <ryuki_dono@yahoo.de>
Bob Friesenhahn schrieb: > > Most applications don't qualify as "serious" applications. For many > applications it is perfectly ok for 12 or 16 bit data is presented > with only 8 bits. This is demonstrated by the fact that hardly any > computer display systems support more than 8 bits of grayscale > resolution. So there is nothing wrong with libtiff offering built-in > support for reading other sizes as long as the user understands that > there is loss. > > There are "serious" applications where 12 or 16 bits are really > required. Those applications will be written to support full resolution. I think so too. In most cases there is no need for accurate data display. If you want to create a simple preview or thumbnails from tiff files the loss through downsampling doesn't matter. It depends on the application. From this point of view there is nothing wrong about a function like TIFFReadRGBAImage when it is clear that there is loss and overhead. For getting the precise data there are allways low level functions. An easy access to the codec is a plus too. I tried to use the default errorhandler and under normal conditions it would be the best solution. Unfortunately I'm missing JPEG support. You can look at the errormessages I get for images like zackthecat.tif. While TIFFReadRGBAImage reads unsupported TIFF files, recovers from errors and give back a NULL, it crashes fatal here. For the moment I stick to the exception throwing.