26 void ReadPGM(FILE* f, Image* image, size_t* height, size_t* width) {  in ReadPGM()  argument
28   CHECK(fscanf(f, "P5\n%lu %lu\n%d\n", width, height, &colors) == 3);  in ReadPGM()
32   for (int i = *height - 1; i >= 0; --i) {  in ReadPGM()
33     ScanLine line = new uint8_t[*width];  in ReadPGM()
35     CHECK(fread(line, 1, *width, f) == *width);  in ReadPGM()
40                    size_t height, size_t width) {  in CalculateDiff()  argument
42     for (size_t j = 0; j < width; ++j) {  in CalculateDiff()
43       diff[i][j] = static_cast<int>(image1[i][j]) - image2[i][j];  in CalculateDiff()
49               size_t height, size_t width, FILE* f) {  in DrawDiff()  argument
50   int max = -1234;  in DrawDiff()  local
53     for (size_t j = 0; j < width; ++j) {  in DrawDiff()
54       if (max < diff[i][j]) max = diff[i][j];  in DrawDiff()
56       int img_min = std::min(255 - image1[i][j], 255 - image2[i][j]);  in DrawDiff()
57       if (max < img_min) max = img_min;  in DrawDiff()
61   int abs_max = -min;  in DrawDiff()
62   if (abs_max < max) abs_max = max;  in DrawDiff()
64   fprintf(f, "P6\n%lu %lu\n%d\n", width, height, abs_max);  in DrawDiff()
66   uint8_t* row = new uint8_t[3 * width];  in DrawDiff()
67   for (int i = height - 1; i >= 0; --i) {  in DrawDiff()
68     for (int j = 0; j < width; ++j) {  in DrawDiff()
69       int min_val = std::min(255 - image1[i][j], 255 - image2[i][j]);  in DrawDiff()
70       int max_val = std::max(min_val, abs(diff[i][j]));  in DrawDiff()
72         row[3 * j + 0] = abs_max - max_val + diff[i][j];  in DrawDiff()
73         row[3 * j + 1] = abs_max - max_val;  in DrawDiff()
74         row[3 * j + 2] = abs_max - max_val + min_val;  in DrawDiff()
76         row[3 * j + 0] = abs_max - max_val;  in DrawDiff()
77         row[3 * j + 1] = abs_max - max_val - diff[i][j];  in DrawDiff()
78         row[3 * j + 2] = abs_max - max_val + min_val;  in DrawDiff()
81     fwrite(row, 1, 3 * width, f);  in DrawDiff()