PNG to GIF

[pratamishus]

Hello people!

 

My problem is as follows: I need to convert a partially transparent PNG to a transparent GIF. Everything works fine except of the background problem. You might know such thing in photoshop as "Matte" for the GIF images. So when I convert my PNG to a GIF I want to set the Matte of the image (for instance #00FF00). This means that I want to set a green background to the PNG image and then set all the parts that are absolutely equal to 00FF00 (0, 255, 0) to become transparent. Also I can't create loops running through each pixel as this loads my server with the amount of requests I have. Here is the part of the code that creates my backround:

 

imagealphablending($image_resized, true);

 

// Create a new transparent color for image

 

$color = imagecolorallocatealpha($image_resized,$back_color[0], $back_color[1], $back_color[2], 127);

 

// Completely fill the background of the new image with allocated color.

 

$color=imagecolorallocate($image_resized, $back_color[0], $back_color[1], $back_color[2]);

 

imagefill($image_resized, 0, 0, $color);

 

// Restore transparency blending

imagesavealpha($image_resized, true);

//$black = imagecolorallocate($image_resized, $back_color[0], $back_color[1], $back_color[2]);

 

// Make the background transparent

imagecolortransparent($image_resized, $color);

 

In the given code: if I remove the "imagefill" line the script works, but the Matte becomes black. If I enable it, background sets up perfectly, but the transparency works wrong. Can anyone tell me what is wrong?

[Cardale]

function png2gif($pngs, $background = array(255, 255, 255), $dest = 'gif'){

    foreach($pngs as $png){
        $size = getimagesize($png);
        $img = imagecreatefrompng($png);
        $image = imagecreatetruecolor($width = $size[0], $height = $size[1]);
        imagefill($image, 0, 0, $bgcolor = imagecolorallocate($image, $background[0], $background[1], $background[2]));
        imagecopyresampled($image, $img, 0, 0, 0, 0, $width, $height, $width, $height);
        imagecolortransparent($image, $bgcolor);
        imagegif($image, str_ireplace('.png', '.gif', $dest.DIRECTORY_SEPARATOR.basename($png)), 100);
        imagedestroy($image);
    }
}

// example
png2gif(glob("icons/*.png"));

 

Sorry if this doesn't help didn't spend much time on it.

[pratamishus]

Hi!

 

Thank you for the reply, but for some reason - it did not work. I know it should be and I have no idea why it isn't working. I have done it in the most stupid way possible, but working:

 

for($z=0; $z<$final_width; $z++)

{

for($y=0; $y<$final_height; $y++)

{

$rgb=imagecolorat($image_resized, $z, $y);

if($rgb)

imagesetpixel($image_resized, $z, $y, $bcolor);

}

}

 

If anyone can suggest a better way, I would thank that person everyday I live