89 lines
2.2 KiB
C++
89 lines
2.2 KiB
C++
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#include "histogram_stretching.h"
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#include "../histogram.h"
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HistogramStretching::HistogramStretching(PNM* img) :
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Transformation(img)
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{
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}
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HistogramStretching::HistogramStretching(PNM* img, ImageViewer* iv) :
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Transformation(img, iv)
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{
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}
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PNM* HistogramStretching::transform()
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{
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int width = image->width();
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int height = image->height();
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PNM* newImage = new PNM(width, height, image->format());
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// Create min values
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int minR = 0;
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int minG = 0;
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int minB = 0;
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int minL = 0;
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// Create max values
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int maxR = 255;
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int maxG = 255;
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int maxB = 255;
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int maxL = 255;
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// Create histogram
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Histogram* histogram = image->getHistogram();
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// Create pointers QHash<int, int>
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QHash<int, int>* R = histogram->get(histogram->RChannel);
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QHash<int, int>* G = histogram->get(histogram->GChannel);
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QHash<int, int>* B = histogram->get(histogram->BChannel);
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QHash<int, int>* L = histogram->get(histogram->LChannel);
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// Increment max values
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for (int i=0; i<256; i++)
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{
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if (R->value(minR) == 0) minR++;
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if (G->value(minG) == 0) minG++;
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if (B->value(minB) == 0) minB++;
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if (L->value(minL) == 0) minL++;
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}
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// Decrement max values
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for (int i=256; i>0; i--)
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{
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if (R->value(maxR) == 0) maxR--;
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if (G->value(maxG) == 0) maxG--;
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if (B->value(maxB) == 0) maxB--;
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if (L->value(maxL) == 0) maxL--;
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}
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// Iterate over pixels
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for (int x=0; x<width; x++)
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{
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for (int y=0; y<height; y++)
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{
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QRgb pixel = image->pixel(x, y);
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// Calculate new values
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int r = (255/(maxR-minR))*(qRed(pixel)-minR);
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int g = (255/(maxG-minG))*(qGreen(pixel)-minG);
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int b = (255/(maxB-minB))*(qBlue(pixel)-minB);
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int l = (255/(maxL-minL))*(qGray(pixel)-minL);
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if (image->format() == QImage::Format_RGB32)
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{
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// Set pixel in RGB32 model
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newImage->setPixel(x, y, QColor(r,g,b).rgb());
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}
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else
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{
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// Set pixel
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newImage->setPixel(x, y, l);
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}
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}
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}
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return newImage;
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}
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