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https://github.com/processing/processing4.git
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47 lines
1.0 KiB
Plaintext
47 lines
1.0 KiB
Plaintext
/**
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* Histogram.
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*
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* Calculates the histogram of an image.
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* A histogram is the frequency distribution
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* of the gray levels with the number of pure black values
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* displayed on the left and number of pure white values on the right.
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*/
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size(200, 200);
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colorMode(RGB, width);
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int[] hist = new int[width];
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// Load an image from the data directory
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// Load a different image by modifying the comments
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PImage a;
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a = loadImage("cdi01_g.jpg");
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image(a, 0, 0);
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// Calculate the histogram
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for (int i=0; i<width; i++) {
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for (int j=0; j<height; j++) {
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hist[int(red(get(i, j)))]++;
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}
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}
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// Find the largest value in the histogram
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float maxval = 0;
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for (int i=0; i<width; i++) {
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if(hist[i] > maxval) {
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maxval = hist[i];
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}
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}
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// Normalize the histogram to values between 0 and "height"
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for (int i=0; i<width; i++) {
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hist[i] = int(hist[i]/maxval * height);
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}
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// Draw half of the histogram (skip every second value)
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stroke(width);
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for (int i=0; i<width; i+=2) {
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line(i, height, i, height-hist[i]);
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}
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