Foxbrush

Create reflection efftect on image

I have written a function that takes an image as parameter and returns the same image with a reflection effect (often seen in WEB 2.0 sites). I have not performance-tested this with large image files, for thumbnails it works fine (requires PHP 4.3.2 or above, or PHP5).

function imagereflection($src_img) {
  $src_height = imagesy($src_img);
  $src_width = imagesx($src_img);
  $dest_height = $src_height + ($src_height / 2);
  $dest_width = $src_width;
 
  $reflected = imagecreatetruecolor($dest_width, $dest_height);
  imagealphablending($reflected, false);
  imagesavealpha($reflected, true);
 
  imagecopy($reflected, $src_img, 0, 0, 0, 0, $src_width, $src_height);
  $reflection_height = $src_height / 2;
  $alpha_step = 80 / $reflection_height;
  for ($y = 1; $y     for ($x = 0; $x   // copy pixel from x / $src_height - y to x / $src_height + y
  $rgba = imagecolorat($src_img, $x, $src_height - $y);
  $alpha = ($rgba & 0x7F000000) >> 24;
  $alpha =  max($alpha, 47 + ($y * $alpha_step));
  $rgba = imagecolorsforindex($src_img, $rgba);
  $rgba = imagecolorallocatealpha($reflected, $rgba['red'], $rgba['green'], $rgba['blue'], $alpha);
  imagesetpixel($reflected, $x, $src_height + $y - 1, $rgba);
    }
  }
 
  return $reflected;
}
?>

This is rather hot-coded. You could go on and extract some of the values as parameters (80 is the transparency start value, $height / 2 is the reflection area...).