gd and animated GIFs

Hi all,

Just playing around with gd and an animated GIF. With the current Windows
build (2.0.34 binaries) and the DLL, I can build and run the example
animation at
http://cvs.php.net/viewvc.cgi/gd/libgd/examples/gif.c?view=markup but I only
see a blank, white image of 100, 100. No frames!

The culprit appears to be this line:

<snip>
gdImageFilledRectangle(im, rand() % 100, rand() % 100, rand() % 100, rand()
% 100, black);
<snip>

If I change it to:

gdImageRectangle(im, rand() % 100, rand() % 100, rand() % 100, rand() % 100,
black);

All runs as it should and a random coloured rectangle with a white interior
is drawn.


For what it's worth, I replaced the program with a quick, tacky one that
slides, expands / contracts or bounces most of the gd objects in a 120, 120
pixel animation. Please check it and possibly replace the demonstration one
with this one if you think it is worth it.

**********************

#include <stdio.h>
#include <stdlib.h>
#include "gd.h"
#include "gdfonts.h"

int main(int argc, char ** argv)
{
   int i = 0;
   FILE * out;
   gdImagePtr img;
   gdImagePtr prev =NULL;
   int white, randColor, blue, cyan, darkgreen, tan, navyblue, powderblue,
red, salmon;

   img = gdImageCreate(120, 120);
   if (!img) {
      fprintf(stderr, "can't create image");
      return 1;
   }

   out = fopen("anim.gif", "wb");
   if (!out) {
      fprintf(stderr, "can't create file %s", "anim.gif");
      return 1;
   }

   white = gdImageColorAllocate(img, 255, 255, 255);
   gdImageGifAnimBegin(img, out, 1, 3);
   char message[6];

   for (i = 0; i < 20; i++) {
      int r, g, b;
      img = gdImageCreate(120, 120);
      gdPoint dataFrame[4];
      dataFrame[0].x = 75+i;
      dataFrame[0].y = 5+i;
      dataFrame[1].x = 95-i;
      dataFrame[1].y = 5+2*i;
      dataFrame[2].x = 95-i;
      dataFrame[2].y = 95+i;
      dataFrame[3].x = 75+i;
      dataFrame[3].y = 99-2*i;
      r = rand() % 255;
      g = rand() % 255;
      b = rand() % 255;

      white = gdImageColorAllocate(img, 255, 255, 255);
      blue = gdImageColorAllocate(img, 0, 0, 255);
      cyan = gdImageColorAllocate(img, 0, 255, 255);
      darkgreen = gdImageColorAllocate(img, 0, 100, 0);
      navyblue = gdImageColorAllocate(img, 0, 0, 128);
      powderblue = gdImageColorAllocate(img, 176, 224, 230);
      red = gdImageColorAllocate(img, 255, 0, 0);
      salmon = gdImageColorAllocate(img, 255, 140, 105);
      tan = gdImageColorAllocate(img, 210, 180, 140);
      randColor = gdImageColorAllocate(img,  r, g, b);

      gdImageFilledPolygon(img, dataFrame, 4, darkgreen);
      gdImageRectangle(img, 5, 5, 3*i, 15+i, blue);
      gdImageFilledRectangle(img, 25, 35+i, 45+3*i, 45+2*i, navyblue);
      gdImageFilledEllipse(img, 75-i, (25+7*i) % 100, 25+i, 22+i,
randColor);
      gdImageString (img, gdFontGetSmall(), 10, 100-i, (unsigned char *)
"Animation", darkgreen);
      itoa(i+1, message, 10);
      gdImageString (img, gdFontGetSmall(), 67, 100-i, (unsigned char *)
message, red);
      gdImageSetThickness(img, i);
      gdImageLine(img, 15+3*i, 15, 105-3*i, 15, tan); // x top axis

      gdImageGifAnimAdd(img, out, 1, 0, 0, 10, 1, prev);

      if(prev) {
         gdImageDestroy(prev);
      }
      prev = img;
   }
   gdImageGifAnimEnd(out);
   fclose(out);
   system("anim.gif");
   
   return 0;
}