ID: 26144 User updated by: sprice at wisc dot edu Reported By: sprice at wisc dot edu Status: Open Bug Type: GD related Operating System: Mac 10.3 PHP Version: 4.3.4 New Comment:
After looking through the source code more, I think that this is caused (at least in part) by always converting the rotated image to a true color image, which always initially has the background color of black. This is also why the background color argument of the imageRotate() function seems to have no effect. This is shown in /ext/gd/libgd/gd.c on lines 2654, 2691, and 2728 (among others). I think a fix to this would be to make GD return a true color image only when the input is true color. Otherwise return an image with palette biased colors. This *should* keep the alpha channel a bit more intact than previously. Don't expect a patch from me any time soon though, because I have homework and classes now, and I only know enough C to be dangerous... Previous Comments: ------------------------------------------------------------------------ [2003-11-05 21:46:56] sprice at wisc dot edu ./configure --with-apxs --with-mysql --with-gd --with- png-dir=/usr/local --with-zlib-dir=/usr --with-jpeg- dir=/usr/local --disable-short-tags (and phpinfo() says it is the bundled, 2.0.15 compat. version) Is this not reproducible? ------------------------------------------------------------------------ [2003-11-05 21:39:11] [EMAIL PROTECTED] And what might have been the configure line you used? If you didn't use the bundled GD library, bogus this yourself.. ------------------------------------------------------------------------ [2003-11-05 19:46:04] sprice at wisc dot edu Tried it with latest/greatest CVS (php4-STABLE -200311060030) and it is still broken. ------------------------------------------------------------------------ [2003-11-05 17:55:24] [EMAIL PROTECTED] This bug has been fixed in CVS. In case this was a PHP problem, snapshots of the sources are packaged every three hours; this change will be in the next snapshot. You can grab the snapshot at http://snaps.php.net/. In case this was a documentation problem, the fix will show up soon at http://www.php.net/manual/. In case this was a PHP.net website problem, the change will show up on the PHP.net site and on the mirror sites in short time. Thank you for the report, and for helping us make PHP better. ------------------------------------------------------------------------ [2003-11-05 17:52:49] sprice at wisc dot edu Description: ------------ ImageRotate() is messing with my alpha channel. Examples to follow. Reproduce code: --------------- <?php header( 'Content-type: image/png' ); $img = ImageCreate(100, 60); $white = ImageColorResolve($img, 255, 255, 255); $almost_clear = ImageColorResolveAlpha($img, 1, 1, 250, 63); ImageFilledRectangle($img, 0, 0, 50, 30, $white); ImageFilledRectangle($img, 10, 10, 100, 60, $almost_clear); ImagePNG($img); // This works //ImagePNG(ImageRotate($img, 90, $almost_clear)); // This is all black ?> Expected result: ---------------- When you run this as is, you get a semitransparent blue rectangle. Actual result: -------------- If you replace the commented out ImagePNG() with the commented one, the alpha channel inverts itself. As you increase the transparency of $almost_clear, it becomes black (in contrast to the non- ImageRotate() line). ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=26144&edit=1
