Merge CV, ver=5.1; ops/methods from HV, and interface from CV where possible

[goodguy/history.git] / cinelerra-5.1 / db / utils / histplot.C

diff --git a/cinelerra-5.1/db/utils/histplot.C b/cinelerra-5.1/db/utils/histplot.C
new file mode 100644 (file)
index 0000000..b0957ca
--- /dev/null
+++ b/cinelerra-5.1/db/utils/histplot.C
@@ -0,0 +1,50 @@
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+
+void hist_eq(unsigned char *data, int len, int n)
+{
+  while( --n >= 0 ) {
+    int hist[256];
+    for( int i=0; i<256; ++i ) hist[i] = 0;
+    unsigned char *bp = data;
+    for( int i=len; --i>=0; ++bp ) ++hist[*bp];
+    for( int t=0, i=0; i<256; ++i ) { t += hist[i];  hist[i] = t; }
+
+    int mn = 0;    while( mn<255 && !hist[mn] ) ++mn;
+    int mx = 256;  while( mx>mn && hist[mx-1]==len ) --mx;
+    double r = (double)(mx - mn) / (256-1);
+    int map[256];  map[0] = 0;  map[255] = 255;
+    double dv = (len-1) / 256., v = dv;
+    for( int i=1; i<255; ++i, v+=dv ) {
+      int j = i * r + mn;
+      map[i] = i * (1-(v - hist[j])/len);
+    }
+//for( int i=0; i<256; ++i ) fprintf(stderr,"%d\n",map[i]);
+    bp = data;
+    for( int i=len; --i>=0; ++bp ) *bp = map[*bp];
+  }
+}
+
+int main(int ac, char **av)
+{
+  FILE *ifp = !strcmp(av[1],"-") ? stdin : fopen(av[1],"r");
+  char line[120];
+  fgets(line,sizeof(line),ifp);
+  fgets(line,sizeof(line),ifp);
+  int w, h;  if( sscanf(line,"%d %d\n",&w,&h) != 2 ) exit(1);
+  fgets(line,sizeof(line),ifp);
+  int len = w*h;
+  unsigned char data[len], *bp = data;
+  for( int ch, i=len; --i>=0 && (ch=getc(ifp)) >= 0; ++bp ) *bp = ch;
+
+  int hist[256]; for( int i=0; i<256; ++i ) hist[i] = 0;
+  bp = data;     for( int i=len; --i>=0; ++bp ) ++hist[*bp];
+  for( int t=0, i=0; i<256; ++i ) { t += hist[i];  hist[i] = t; }
+  FILE *ofp = popen("gnuplot -e \"set terminal png; plot \\\"-\\\" with lines\" | xv - &","w");
+  for( int i=0; i<256; ++i ) fprintf(ofp,"%d\n",hist[i]);
+  fclose(ofp);
+  if( ifp != stdin ) fclose(ifp);
+  return 0;
+}
+