--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Meerwald-dir/cmp_ppm.c	Fri Dec 20 13:08:59 2024 +0100
@@ -0,0 +1,270 @@
+#include "wm.h"
+#include "netpbm/ppm.h"
+
+#define LUMINANCE 1
+#define RED 2
+#define GREEN 4
+#define BLUE 8
+
+char *progname;
+
+void usage(void) {
+  fprintf(stderr, "usage: %s -c name [-C] [-h] [-m n] [-o file] [-pP] -i file file\n\n", progname);
+  fprintf(stderr, "\t-c name\t\tcolor component (default luminance)\n");
+  fprintf(stderr, "\t\t\teg. red, green, blue, luminance\n");
+  fprintf(stderr, "\t-C\t\tprint PSNR value only\n");
+  fprintf(stderr, "\t-h\t\tprint usage\n");
+  fprintf(stderr, "\t-i file\t\toriginal image file\n");
+  fprintf(stderr, "\t-m n\t\tmultiplication factor (default 16)\n");
+  fprintf(stderr, "\t-o file\t\toutput file\n");
+  fprintf(stderr, "\t-p\t\tprint PSNR, RMS and MSE\n");
+  fprintf(stderr, "\t-P\t\tonly print PSNR, RMS and MSE, no difference image\n");
+  exit(0);
+}
+
+int main(int argc, char *argv[]) {
+
+  FILE *in = stdin;
+  FILE *out = stdout;
+  FILE *orig = NULL;
+
+  pixel **input_image;
+  pixel **orig_image;
+
+  char output_name[MAXPATHLEN] = "(stdout)";
+  char input_name[MAXPATHLEN] = "(stdin)";
+  char orig_name[MAXPATHLEN];
+
+  int in_cols, in_rows, in_format;
+  pixval in_maxval;
+  int orig_cols, orig_rows, orig_format;
+  pixval orig_maxval;
+  int cols, rows;
+  pixval maxval;
+  int col, row;
+
+  int c;
+
+  double error = 0.0;
+  int print_psnr = 0;
+  int print_psnr_only = 0;
+  int print_psnr_value_only = 0;
+
+  int m = 16;
+  int component = 0;
+  int component_default = LUMINANCE;
+  int min, max;
+
+  progname = argv[0];
+
+  ppm_init(&argc, argv);
+
+#ifdef __EMX__
+  _fsetmode(in, "b");
+  _fsetmode(out, "b");
+#endif
+
+  while ((c = getopt(argc, argv, "Cc:h?i:m:o:pP")) != EOF) {
+    switch (c) {
+      case 'C':
+        print_psnr_value_only = 1;
+        print_psnr_only = 1;
+        break;
+      case 'c':
+        if (!strcasecmp(optarg, "RED") || toupper(*optarg) == 'R')
+          component |= RED;
+        else if (!strcasecmp(optarg, "GREEN") || toupper(*optarg) == 'G')
+          component |= GREEN;
+        else if (!strcasecmp(optarg, "BLUE") || toupper(*optarg) == 'B')
+          component |= BLUE;
+        else if (!strcasecmp(optarg, "LUMINANCE") || toupper(*optarg) == 'L')
+          component |= LUMINANCE;
+        else
+          fprintf(stderr, "%s: unknown color component %s\n", progname, optarg);
+        break;
+      case 'h':
+      case '?':
+        usage();
+        break;
+      case 'i':
+        if ((orig = fopen(optarg, "rb")) == NULL) {
+          fprintf(stderr, "%s: unable to open original image file %s\n", progname, optarg);
+          exit(1);
+        }
+        strcpy(orig_name, optarg);
+        break;
+      case 'm':
+        m = atoi(optarg);
+        if (m <= 0) {
+          fprintf(stderr, "%s: multiplication factor %d out of range\n", progname, m);
+          exit(1);
+        }
+        break;
+      case 'o':
+        if ((out = fopen(optarg, "wb")) == NULL) {
+          fprintf(stderr, "%s: unable to open output file %s\n", progname, optarg);
+          exit(1);
+        }
+        strcpy(output_name, optarg);
+        break;
+      case 'p':
+        print_psnr = 1;
+        break;
+      case 'P':
+        print_psnr_only = 1;
+        break;
+    }
+  }
+
+  argc -= optind;
+  argv += optind;
+
+  if (argc > 1) {
+    usage();
+    exit(1);
+  }
+
+  if (argc == 1 && *argv[0] != '-') {
+    if ((in = fopen(argv[0], "rb")) == NULL) {
+      fprintf(stderr, "%s: unable to open input file %s\n", progname, argv[0]);
+      exit(1);
+    }
+    else
+      strcpy(input_name, argv[0]);
+  }
+  
+  if (!orig) {
+    fprintf(stderr, "%s: original image file not specified, use -i file option\n", progname);
+    exit(1);
+  }
+
+  if (!component) {
+    if (component_default)
+      component = component_default;
+    else {
+      fprintf(stderr, "%s: color component(s) to compare not specified, use -c name option\n", progname);
+      exit(1);
+    }
+  }
+
+  if (component & LUMINANCE && component & (RED | GREEN | BLUE)) {
+    fprintf(stderr, "%s: unable to compare luminance AND color component\n", progname);
+    exit(1);
+  }
+
+  ppm_readppminit(in, &in_cols, &in_rows, &in_maxval, &in_format);
+
+  ppm_readppminit(orig, &orig_cols, &orig_rows, &orig_maxval, &orig_format);
+
+  if (in_cols != orig_cols || in_rows != orig_rows) {
+    fprintf(stderr, "%s: input image %s does not match dimensions of original image %s\n", progname, input_name, orig_name);
+    exit(1);
+  }
+
+  cols = in_cols;
+  rows = in_rows;
+  maxval = in_maxval;
+
+  input_image = ppm_allocarray(cols, rows);
+
+  for (row = 0; row < rows; row++)
+      ppm_readppmrow(in, input_image[row], cols, in_maxval, in_format);
+
+  fclose(in);
+
+  orig_image = ppm_allocarray(cols, rows);
+
+  for (row = 0; row < rows; row++)
+      ppm_readppmrow(orig, orig_image[row], cols, orig_maxval, orig_format);
+
+  fclose(orig);
+
+  if (component & LUMINANCE)
+    min = max = abs(PPM_LUMIN(input_image[0][0]) - PPM_LUMIN(orig_image[0][0]));
+  else {
+    if (component & RED)
+      min = max = abs(PPM_GETR(input_image[0][0]) - PPM_GETR(orig_image[0][0]));
+    else if (component & GREEN)
+      min = max = abs(PPM_GETG(input_image[0][0]) - PPM_GETG(orig_image[0][0]));
+    else if (component & BLUE)
+      min = max = abs(PPM_GETB(input_image[0][0]) - PPM_GETB(orig_image[0][0]));
+    else
+      min = max = 0;
+  }
+
+  for (row = 0; row < rows; row++) {
+    pixel *pi = input_image[row];
+    pixel *po = orig_image[row];
+
+    for (col = 0; col < cols; col++) {
+      int diff=0;
+
+      if (component & LUMINANCE) {
+        pixval l;
+        diff = abs(PPM_LUMIN(*pi) - PPM_LUMIN(*po));
+        error += sqr(PPM_LUMIN(*pi) - PPM_LUMIN(*po));
+        l = PIXELRANGE(ROUND(abs(PPM_LUMIN(*pi) - PPM_LUMIN(*po)) * m));
+        PPM_ASSIGN(*pi, l, l, l);
+      }
+      else {
+        if (component & RED) {
+          diff = abs(PPM_GETR(*pi) - PPM_GETR(*po));
+          error += sqr(PPM_GETR(*pi) - PPM_GETR(*po));
+          PPM_PUTR(*pi, PIXELRANGE(abs(PPM_GETR(*pi) - PPM_GETR(*po)) * m));
+        }
+        else 
+          PPM_PUTR(*pi, 0);
+        if (component & GREEN) {
+          diff = abs(PPM_GETG(*pi) - PPM_GETG(*po));
+          error += sqr(PPM_GETG(*pi) - PPM_GETG(*po));
+          PPM_PUTG(*pi, PIXELRANGE(abs(PPM_GETG(*pi) - PPM_GETG(*po)) * m));
+        }
+        else 
+          PPM_PUTG(*pi, 0);
+        if (component & BLUE) {
+          diff = abs(PPM_GETB(*pi) - PPM_GETB(*po));
+          error += sqr(PPM_GETB(*pi) - PPM_GETB(*po));
+          PPM_PUTB(*pi, PIXELRANGE(abs(PPM_GETB(*pi) - PPM_GETB(*po)) * m));
+        }
+        else
+          PPM_PUTB(*pi, 0);
+      }
+
+      if (diff < min) min = diff;
+      if (diff > max) max = diff;
+      pi++;
+      po++;
+    }
+  }
+
+  if (!print_psnr_only) {
+    ppm_writeppminit(out, cols, rows, maxval, 0);
+    for (row = 0; row < rows; row++)
+      ppm_writeppmrow(out, input_image[row], cols, maxval, 0);
+
+    fclose(out);
+  }
+
+  ppm_freearray(input_image, rows);
+  ppm_freearray(orig_image, rows);
+
+  if (print_psnr || print_psnr_only) {
+    double mse = error / (double) (cols * rows);
+    double rmse = sqrt(mse);
+    double psnr = 20.0 * log(255.0 / rmse) / log(10.0);
+    FILE *print = print_psnr_only ? out : stderr;
+    if (!print_psnr_value_only) { 
+      if (mse > 0.0)
+        fprintf(print, "PSNR: %lf dB\n", psnr);
+      else
+        fprintf(print, "PSNR: inf\n");
+      fprintf(print, "RMS: %lf\n", rmse);
+      fprintf(print, "MSE: %lf\n", mse);
+      fprintf(print, "dmin, dmax: %d, %d\n", min, max);
+    }
+    else
+      fprintf(print, "%lf\n", mse > 0.0 ? psnr : 100.0);
+  }
+
+  exit(0);
+}