#21763 [Opn->Bgs]: imagecolortransparent &/or imagecolorallocate not working with 2- and 4-bit png

ID: 21763 Updated by: iliaa@php.net Reported By: tuxedobob@mac.com -Status: Open +Status: Bogus Bug Type: GD related Operating System: Mac OS X 10.2.3 PHP Version: 4.3.0 New Comment: Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php You are making an existing color transparent therefor you don't need to do ImageColorAllocate(). Simply do imagecolorat() on the pixel with the color you wish to make transparent and use the return value as the 2nd argument to imagecolortransparent(). In your particular case this can be done with: $black = ImageColorAt($image2, 0, 0); Previous Comments: ------------------------------------------------------------------------ [2003-01-20 15:51:18] sniper@php.net When you give feedback, please DO NOT USE the page behind the 'Add Comment' link!! ------------------------------------------------------------------------ [2003-01-20 12:20:57] tuxedobob@mac.com I'm using the bundled library. And since there seems to be no way to upload them (even though they're about 5K total), I'll just put the images here: Orc: http://homepage.mac.com/tuxedobob/Orc.png Board: http://homepage.mac.com/tuxedobob/Board.png ------------------------------------------------------------------------ [2003-01-20 09:39:44] iliaa@php.net Please provide the two images used in your example. Also, are you using the bundled GD library or the non-bundled one? ------------------------------------------------------------------------ [2003-01-20 02:28:08] tuxedobob@mac.com In the following script: <?php $image2 = ImageCreateFromPNG('images/Monsters/Orc.png'); $image = ImageCreateFromPNG('images/Board.png'); $black = ImageColorAllocate($image2, 0, 0, 0); imagecolortransparent($image2, $black); imagecopy($image, $image2, 40*2+8, 40*2+8, 0, 0, 39, 39); header("Content-type: image/png"); ImagePNG($image); imagedestroy($image); imagedestroy($image2); ?> what I expect to happen is that the black in the 'Orc.png' image will become transparent when it is copied onto 'Board.png'. This doesn't happen. The transparency is not recognized at all. More info: Orc.png is a 2-bit PNG, with black occupying two of the colors. (It doesn't work even if it only has one.) Board.png is a 4-bit PNG with 6 distinct colors (11 copies of black). If I change the line to imagecolortransparent('$image2, imagecolorat($image2, 0, 0); it works correctly. If I change the line use either 2 or 3, as in imagecolortransparent('$image2, 3); it works depending on which black (index no. 2 or 3) is actually in the image. There may be no way around this except to have imagecolortransparent check by RGB values rather than an index number. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=21763&edit=1