single pixel manipulation with php GD

Question

First I\'m referring to a previous question Change image per pixel and save to db

I found that the html5 canvas isn\'t suitable because it\'s hard to keep the source-ima

Answer 1

With the help of ogres I got it partially working.

What I do is manipulating a toplayer and after the manipulation, merge it with function imagecopy with the source-image. The output is a jpg image.

The manipulation of the toplayer is done with this code

for ($y = 0; $y < imagesy($img); $y++) {
for ($x = 0; $x < imagesx($img); $x++) {
$img = imagecreatefrompng("thecover.png");
    imagealphablending($img, false); // Turn off blending
    $white_color_transparent = imagecolorallocatealpha($img, 255, 255, 255, 127);

            $rgb = imagecolorat($img, $x, $y);
            $pixel_color = imagecolorsforindex($img, $rgb);
            if ($pixel_color['red'] == 255 && $pixel_color['green'] == 255 && $pixel_color['blue'] == 255){
                for ($i = 0; $i < 200; $i++) {
                    imagesetpixel($img, rand(0,300), rand(0,300), $white_color_transparent);
                    }
            }
}
}

The color of the toplayer is white, RGB (0,0,0). The script checks for that color and sets, at this point, 200 random pixels to transparent.

It's setting a lot of pixels to transparent, but not the given 200.

Someone who can help me out.