CODEWITHSUNDEEP
phpgd
Strawberry
Strawberry

Reputation: 67888

imagepng() and transparency in GD library with PHP

When using the function imagepng() in PHP, how can I make sure the images that I save are saved with a transparent background?

Upvotes: 20

Views: 43725

Answers (4)

Eric
Eric

Reputation: 767

Here is an example of the imagecolortransparent function (if it helps):

<?php
// Create a 55x30 image
$im = imagecreatetruecolor(55, 30);
$red = imagecolorallocate($im, 255, 0, 0);
$black = imagecolorallocate($im, 0, 0, 0);

// Make the background transparent
imagecolortransparent($im, $black);

// Draw a red rectangle
imagefilledrectangle($im, 4, 4, 50, 25, $red);

// Save the image
imagepng($im, './imagecolortransparent.png');
imagedestroy($im);
?>

Upvotes: 10

user2731504
user2731504

Reputation: 187

Here is the example

     $newimage = imagecreatetruecolor($dst_w, $dst_h);
     imagealphablending($newimage, false);
     imagesavealpha($newimage, true);
     $transparentindex = imagecolorallocatealpha($newimage, 255, 255, 255, 127);
     imagefill($newimage, 0, 0, $transparentindex);

Upvotes: 18

lamelas
lamelas

Reputation: 872

There's a function called imagecolortransparent that allows you to set which color is made transparent. I don't know if this answers your question.

Upvotes: 0

mauris
mauris

Reputation: 43619

Simply do this:

imagealphablending($img, false);
imagesavealpha($img, true);

Before outputting. Make sure that all source files (if you used any) are set to PNG 32-bit with transparency - if not the output may differ with black background or transparency does not comply.

Upvotes: 57

Related Questions