text: #include "gd.h"
  
  BGD_DECLARE(int) gdImagePixelate(gdImagePtr im, int block_size, const unsigned int mode)
  {
  	int x, y;
  
  	if (block_size <= 0) {
  		return 0;
  	} else if (block_size == 1) {
  		return 1;
  	}
  	switch (mode) {
  	case GD_PIXELATE_UPPERLEFT:
  		for (y = 0; y < im->sy; y += block_size) {
  			for (x = 0; x < im->sx; x += block_size) {
  				if (gdImageBoundsSafe(im, x, y)) {
  					int c = gdImageGetPixel(im, x, y);
  					gdImageFilledRectangle(im, x, y, x + block_size - 1, y + block_size - 1, c);
  				}
  			}
  		}
  		break;
  	case GD_PIXELATE_AVERAGE:
  		for (y = 0; y < im->sy; y += block_size) {
  			for (x = 0; x < im->sx; x += block_size) {
  				int a, r, g, b, c;
  				int total;
  				int cx, cy;
  
  				a = r = g = b = c = total = 0;
  				/* sampling */
  				for (cy = 0; cy < block_size; cy++) {
  					for (cx = 0; cx < block_size; cx++) {
  						if (!gdImageBoundsSafe(im, x + cx, y + cy)) {
  							continue;
  						}
  						c = gdImageGetPixel(im, x + cx, y + cy);
  						a += gdImageAlpha(im, c);
  						r += gdImageRed(im, c);
  						g += gdImageGreen(im, c);
  						b += gdImageBlue(im, c);
  						total++;
  					}
  				}
  				/* drawing */
  				if (total > 0) {
  					c = gdImageColorResolveAlpha(im, r / total, g / total, b / total, a / total);
  					gdImageFilledRectangle(im, x, y, x + block_size - 1, y + block_size - 1, c);
  				}
  			}
  		}
  		break;
  	default:
  		return 0;
  	}
  	return 1;
  }
  