115 lines
4.1 KiB
C++
115 lines
4.1 KiB
C++
#include <iostream>
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#define STB_IMAGE_WRITE_IMPLEMENTATION
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#include "stb_image_write.h"
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#define STB_IMAGE_IMPLEMENTATION
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#include "stb_image.h"
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struct Pixel {
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unsigned char r, g, b, a;
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};
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int index(int x, int y, int w) {
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return x+y*w;
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}
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int main(int argc, char** argv) {
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if (argc < 2) {
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std::cout << "Incorrect usage, use like ./output.o <imagepath>" << std::endl;
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return 0;
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}
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int w, h, c;
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Pixel* image = (Pixel*)stbi_load(*(argv + 1), &w, &h, &c, 4);
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if (image == NULL){
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std::cout << "Invalid image: " << stbi_failure_reason() << std::endl;
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return 0;
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}
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// Pixel* image = (Pixel*)malloc(sizeof(Pixel) * w * h * 4);
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// Pixel* image = (Pixel*)stbi_load(*(argv + 1), &w, &h, &c, 4);
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// Pixel* image = new Pixel[w * h * 4];
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// for (int y = 0; y < h - 1; y++) {
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// for (int x = 1; x < w - 1; x++) {
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// image[x + y * w] = {255, 255, 255, 255};
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// }
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// }
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int colComplexity = 3;
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for (int y = 1; y < h - 1; y++) {
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for (int x = 1; x < w - 1; x++) {
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image[x + y * w].r = round(colComplexity * image[x + y * w].r / 255) * (255 / colComplexity);
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image[x + y * w].g = round(colComplexity * image[x + y * w].g / 255) * (255 / colComplexity);
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image[x + y * w].b = round(colComplexity * image[x + y * w].b / 255) * (255 / colComplexity);
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float errorR = image[x + y * w].r - image[x + y * w].r;
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float errorG = image[x + y * w].g - image[x + y * w].g;
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float errorB = image[x + y * w].b - image[x + y * w].b;
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int i = index(x+1, y, w);
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image[i].r = (float)image[i].r + errorR * (7.0f / 16.0f);
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image[i].g = (float)image[i].g + errorG * (7.0f / 16.0f);
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image[i].b = (float)image[i].b + errorB * (7.0f / 16.0f);
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i = index(x-1, y+1, w);
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image[i].r = (float)image[i].r + errorR * (3.0f / 16.0f);
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image[i].g = (float)image[i].g + errorG * (3.0f / 16.0f);
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image[i].b = (float)image[i].b + errorB * (3.0f / 16.0f);
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i = index(x, y+1, w);
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image[i].r = (float)image[i].r + errorR * (5.0f / 16.0f);
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image[i].g = (float)image[i].g + errorG * (5.0f / 16.0f);
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image[i].b = (float)image[i].b + errorB * (5.0f / 16.0f);
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i = index(x+1, y+1, w);
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image[i].r = (float)image[i].r + errorR * (1.0f / 16.0f);
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image[i].g = (float)image[i].g + errorG * (1.0f / 16.0f);
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image[i].b = (float)image[i].b + errorB * (1.0f / 16.0f);
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// int i = index(x+1, y, w);
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// float r = image[i].r;
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// float g = image[i].g;
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// float b = image[i].b;
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// r = r + errorR * 7/16.0;
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// g = g + errorG * 7/16.0;
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// b = b + errorB * 7/16.0;
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// image[i] = {r, g, b, 255};
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// i = index(x-1, y+1, w);
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// r = image[i].r;
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// g = image[i].g;
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// b = image[i].b;
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// r = r + errorR * 3/16.0;
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// g = g + errorG * 3/16.0;
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// b = b + errorB * 3/16.0;
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// image[i] = {r, g, b, 255};
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// i = index(x, y+1, w);
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// r = image[i].r;
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// g = image[i].g;
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// b = image[i].b;
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// r = r + errorR * 5/16.0;
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// g = g + errorG * 5/16.0;
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// b = b + errorB * 5/16.0;
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// image[i] = {r, g, b, 255};
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// i = index(x+1, y+1, w);
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// r = image[i].r;
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// g = image[i].g;
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// b = image[i].b;
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// r = r + errorR * 1/16.0;
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// g = g + errorG * 1/16.0;
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// b = b + errorB * 1/16.0;
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// image[i] = {r, g, b, 255};
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// pixel[x + 1][y ] := pixel[x + 1][y ] + quant_error * 7 / 16
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// pixel[x - 1][y + 1] := pixel[x - 1][y + 1] + quant_error * 3 / 16
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// pixel[x ][y + 1] := pixel[x ][y + 1] + quant_error * 5 / 16
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// pixel[x + 1][y + 1] := pixel[x + 1][y + 1] + quant_error * 1 / 16
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}
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}
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stbi_write_png("output.png", w, h, 4, (unsigned char*)image, 0);
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}
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