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invert_explicitly.cxx | ![]() |
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Invert an image file (create a negative) by coding the loop explicitly
Usage: invert_explicitly infile outfile
/************************************************************************/ /* */ /* Copyright 1998-2002 by Ullrich Koethe */ /* Cognitive Systems Group, University of Hamburg, Germany */ /* */ /* This file is part of the VIGRA computer vision library. */ /* ( Version 1.3.2, Jan 27 2005 ) */ /* You may use, modify, and distribute this software according */ /* to the terms stated in the LICENSE file included in */ /* the VIGRA distribution. */ /* */ /* The VIGRA Website is */ /* http://kogs-www.informatik.uni-hamburg.de/~koethe/vigra/ */ /* Please direct questions, bug reports, and contributions to */ /* koethe@informatik.uni-hamburg.de */ /* */ /* THIS SOFTWARE IS PROVIDED AS IS AND WITHOUT ANY EXPRESS OR */ /* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */ /* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ /* */ /************************************************************************/ #include <iostream> #include "vigra/stdimage.hxx" #include "vigra/stdimagefunctions.hxx" #include "vigra/impex.hxx" using namespace vigra; int main(int argc, char ** argv) { if(argc != 3) { std::cout << "Usage: " << argv[0] << " infile outfile" << std::endl; std::cout << "(supported formats: " << vigra::impexListFormats() << ")" << std::endl; return 1; } try { vigra::ImageImportInfo info(argv[1]); if(info.isGrayscale()) { vigra::BImage in(info.width(), info.height()); vigra::BImage out(info.width(), info.height()); importImage(info, destImage(in)); // create image iterator that points to upper left corner // of source image vigra::BImage::Iterator sy = in.upperLeft(); // create image iterator that points past the lower right corner of // source image (similarly to the past-the-end iterator in the STL) vigra::BImage::Iterator send = in.lowerRight(); // create image iterator that points to upper left corner // of destination image vigra::BImage::Iterator dy = out.upperLeft(); // iterate down the first column of the images for(; sy.y != send.y; ++sy.y, ++dy.y) { // create image iterator that points to the first // pixel of the current row of the source image vigra::BImage::Iterator sx = sy; // create image iterator that points to the first // pixel of the current row of the destination image vigra::BImage::Iterator dx = dy; // iterate across current row for(; sx.x != send.x; ++sx.x, ++dx.x) { // calculate negative gray value *dx = 255 - *sx; } } exportImage(srcImageRange(out), vigra::ImageExportInfo(argv[2])); } else { vigra::BRGBImage in(info.width(), info.height()); vigra::BRGBImage out(info.width(), info.height()); importImage(info, destImage(in)); vigra::RGBValue<int> offset(255, 255, 255); // create image iterator that points to upper left corner // of source image vigra::BRGBImage::Iterator sy = in.upperLeft(); // create image iterator that points past the lower right corner of // source image (similarly to the past-the-end iterator in the STL) vigra::BRGBImage::Iterator send = in.lowerRight(); // create image iterator that points to upper left corner // of destination image vigra::BRGBImage::Iterator dy = out.upperLeft(); // iterate down the first column of the images for(; sy.y != send.y; ++sy.y, ++dy.y) { // create image iterator that points to the first // pixel of the current row of the source image vigra::BRGBImage::Iterator sx = sy; // create image iterator that points to the first // pixel of the current row of the destination image vigra::BRGBImage::Iterator dx = dy; // iterate across current row for(; sx.x != send.x; ++sx.x, ++dx.x) { // calculate negative color *dx = offset - *sx; } } exportImage(srcImageRange(out), vigra::ImageExportInfo(argv[2])); } } catch (vigra::StdException & e) { std::cout << e.what() << std::endl; return 1; } return 0; }
© Ullrich Köthe (koethe@informatik.uni-hamburg.de) |
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