Imported Upstream version 0.72

tools/decimate.c

@@ -0,0 +1,127 @@
+/*  pngpack: lossless image compression for a series of screen shots
+ *  Copyright (C) 2005-2009 Carsten Gnoerlich.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA,
+ *  or direct your browser at http://www.gnu.org.
+ */
+
+#include <errno.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "pngio.h"
+#include "memory.h"
+
+/*
+ * Thumbnail generation
+ */
+
+void SaveThumbnail(Image *pi, char *name, int thumb_size, char *thumb_dir)
+{  Image *thumb;
+   char tname[strlen(thumb_dir)+strlen(name)+2];
+   double ratio, inv_ratio;
+   unsigned int size, *pixel;
+   int i,j;
+
+   /* sanity check */
+
+   if(pi->width < thumb_size && pi->height < thumb_size)
+   {  fprintf(stdout, "... NOT creating thumbnail because of image size (%dx%d)\n",
+	      pi->width, pi->height);
+      return;
+   }
+
+   /* Create thumbnail copy from image */
+
+   thumb=malloc(sizeof(Image));
+   memcpy(thumb, pi, sizeof(Image));
+
+   if(thumb->width > thumb->height) 
+        inv_ratio = (double)thumb->width/(double)thumb_size;
+   else inv_ratio = (double)thumb->height/(double)thumb_size;
+
+   ratio = 1.0/inv_ratio;
+
+   thumb->width  = (int)((double)thumb->width*ratio+0.5);
+   thumb->height = (int)((double)thumb->height*ratio+0.5);
+
+   sprintf(tname, "%s/%s", thumb_dir, name);
+
+   fprintf(stdout, "... and %dx%d thumbnail %s\n", thumb->width, thumb->height, tname);
+
+   size = thumb->width * thumb->height;
+   thumb->bytesize = sizeof(unsigned int) * size;
+   thumb->image = malloc(thumb->bytesize);
+   if(!thumb->image) Stop("out of memory for image");
+
+   /*
+    * Decimate the image 
+    */
+
+   pixel = thumb->image;
+   for(i=0; i<thumb->height; i++)
+      for(j=0; j<thumb->width; j++)
+      {  double first_x = j*inv_ratio;
+	 double first_y = i*inv_ratio;
+	 double last_x  = (j+1)*inv_ratio;
+	 double last_y  = (i+1)*inv_ratio;
+	 double area = 0.0;
+	 int x0 = floor(first_x);
+	 int x1 = ceil(last_x);
+	 int y0 = floor(first_y);
+	 int y1 = ceil(last_y);
+	 int x,y;
+	 double c1,c2,c3,c4;
+	 unsigned int ci1,ci2,ci3,ci4;
+#if 0
+	 printf("%d %d -> (%d %d) - (%d %d)\n", j,i, x0,y0, x1, y1);
+	 printf("%f %f %f %f\n", first_x, first_y, last_x, last_y);
+	 printf("%f %f\n", ratio, inv_ratio);
+#endif
+	 if(x1>=pi->width) x1=pi->width-1;
+	 if(y1>=pi->height) y1=pi->height-1;
+
+	 c1 = c2 = c3 = c4 = 0.0;
+	 for(y=y0; y<=y1; y++)
+	 {  double ysize = 1.0;
+	    double size;
+
+	    if(y<y0) ysize = 1.0-(y0-y);
+	    if(y>y1) ysize = 1.0-(y-y1);
+
+	    for(x=x0; x<=x1; x++)
+	    {  int idx = x+y*pi->width;
+	       size = ysize;
+	       if(x<x0) size *= (1.0-(x0-x));
+	       if(x>x1) size *= (1-0-(x-x1));
+
+	       c1 += size * ((pi->image[idx]>>24)&0xff);
+	       c2 += size * ((pi->image[idx]>>16)&0xff);
+	       c3 += size * ((pi->image[idx]>> 8)&0xff);
+	       c4 += size * ((pi->image[idx]    )&0xff);
+	       area += size;
+	    }
+	 }
+
+	 ci1 = c1/area; ci2 = c2/area; ci3 = c3/area; ci4 = c4/area;
+	 *pixel++ = (ci1<<24) | (ci2<<16) | (ci3<<8) | ci4;
+      }
+
+   SavePNG(thumb, tname);
+
+   free(thumb->image);
+   free(thumb);
+}