<!-- manual page source format generated by PolyglotMan v3.2, --> <!-- available at http://polyglotman.sourceforge.net/ --> <html> <head> <title>IM_XYZ2disp(3) manual page</title> </head> <body bgcolor='white'> <a href='#toc'>Table of Contents</a><p> <h2><a name='sect0' href='#toc0'>Name</a></h2> im_LabQ2Lab, im_Lab2LabQ, im_LabQ2LabS, im_LabS2LabQ, im_Lab2LabS, im_LabS2Lab - pack and unpack LABPACK images. <h2><a name='sect1' href='#toc1'>Synopsis</a></h2> #include <vips/vips.h> <p> int im_LabQ2Lab(in, out) <br> IMAGE *in, *out; <p> int im_Lab2LabQ(in, out) <br> IMAGE *in, *out; <p> int im_Lab2LabS(in, out) <br> IMAGE *in, *out; <p> int im_LabS2LabQ(in, out) <br> IMAGE *in, *out; <p> int im_LabS2Lab(in, out) <br> IMAGE *in, *out; <p> int im_LabQ2LabS(in, out) <br> IMAGE *in, *out; <p> <h2><a name='sect2' href='#toc2'>Description</a></h2> These functions pack and unpack LAB images. <p> LabQ is Lab packed in to 4 unsigned chars, with the Coding field set to LABPACK. It counts as a coded type, since most operations will not give the correct result on an image of this type. This is the MARC image type. Bits are allocated as 10 for L and 11 for each of a and b. The first three bytes contain the 8 most significant bits of Lab respectively, the final byte has 2/3/3 bits (MSB on left) of Lab respectively. <p> im_LabQ2Lab() and im_Lab2LabQ() convert LABPACK images to three band float images, scaled to look sensible to humans. This is the most convenient LAB format for development work, but is rather slow. <p> im_LabQ2LabS() and im_LabS2LabQ() convert LABPACK to and from three band signed short images. L is shifted and masked to be in the range [0,32767], a and b are shifted and masked to lie in [-32768,32767]. This is the best computational LAB format, combining precision and speed. Programs such as <a href='conv.1X.html'>conv(1X)</a> and <a href='similarity.1X.html'>similarity(1X)</a> , which can operate directly on LABPACK images, unpack to LabS for computation. <p> <h2><a name='sect3' href='#toc3'>Return Value</a></h2> The functions return 0 on success and -1 on error. <h2><a name='sect4' href='#toc4'>See Also</a></h2> <a href='im_col_XYZ2rgb.3.html'>im_col_XYZ2rgb(3)</a> , <a href='im_dE_fromdisp.3.html'>im_dE_fromdisp(3)</a> , <a href='im_XYZ2disp.3.html'>im_XYZ2disp(3)</a> . <h2><a name='sect5' href='#toc5'>Copyright</a></h2> National Gallery, 1990 - 1993 <h2><a name='sect6' href='#toc6'>Author</a></h2> J. Cupitt - 21/7/93 <p> <hr><p> <a name='toc'><b>Table of Contents</b></a><p> <ul> <li><a name='toc0' href='#sect0'>Name</a></li> <li><a name='toc1' href='#sect1'>Synopsis</a></li> <li><a name='toc2' href='#sect2'>Description</a></li> <li><a name='toc3' href='#sect3'>Return Value</a></li> <li><a name='toc4' href='#sect4'>See Also</a></li> <li><a name='toc5' href='#sect5'>Copyright</a></li> <li><a name='toc6' href='#sect6'>Author</a></li> </ul> </body> </html>
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