> -----Original Message----- > From: Pierre-Alain Joye [mailto:[EMAIL PROTECTED]] > Sent: Thursday, February 20, 2003 9:02 PM > To: Jukka Holappa > Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED] > Subject: Re: [PHP-DEV] [PATCH] imagesavealpha() > > > On Thu, 20 Feb 2003 22:17:48 +0200 > Jukka Holappa <[EMAIL PROTECTED]> wrote: > > It sounds good, I will run tests today and commit it to the HEAD.
I sent in a patch on 1/2/2003 to fix various issues blocking use of transparent truecolor PNGs in PHP and its bundled libgd that included adding imagesavealpha() to PHP, did my patch fall out of the loop? I've attached the original message about this and here's the link to the patch: http://www-cs.ucsd.edu/~sbrown/php-4.3.0-gd-swb.patch
--- Begin Message --- Title: Patch fixing truecolor transparency issues in libgd/php (against PHP 4.3.0)It seems libgd development has started up again, so I'll toss my truecolor fixes onto the pile. Some were already fixed in the version that comes with PHP-4.3.0 (I had originally patched against gd 2.0.1 beta), so these are the remaining issues I know of against PHP 4.3.0's dist.
The patch is here: http://www-cs.ucsd.edu/~sbrown/php-4.3.0-gd-swb.patch .
This fixes truecolor PNG image loading trying to extract the transparency colors from the boolean trueColor flag rather than the transparent color, fixes a few issues in the truecolor->palette code with how transparency is handled, and adds gd's imageSaveAlpha to PHP. I also changed a fix that went in that looked like it wasn't fixed quite right, gd.c's image copy throwing out alpha when copying palette to truecolor. Very few browsers support alpha transparent PNGs so imageSaveAlpha must be set false to generate boolean transparency. PHP 4.3.0 (or its included gd) seems to default this to false now anyway (gd used to default to true).
TrueColor PNG boolean transparency works great in all modern browsers except desktop win32 IE. It's your enemy on this. Funny thing is, IE 3.02 for the Pocket PC works beautifully. Go figure. Also, unless it's been changed since I first wrote this, gd in truecolor mode always assigns color 0 as black (0,0,0). IE (5+6) always take color index 0 as transparent regardless of what index you tell it to use it seems, so the hack is to always set black as your transparent color so transparent palettized PNGs will work. Rather than fix these issues, Microsoft has some hacky IE-specific DirectX HTML goo (http://webfx.eae.net/dhtml/pngbehavior/pngbehavior.html) to load transparent truecolor PNGs. Problem is, it's also buggy and won't work with HTTPS addresses last I tried! If you need to spit transparent truecolor PNGs out over HTTPS, you need to browser detect these PNG-challenged IEs and do a imageTrueColorToPalette to dither it down to a palettized PNG right before you output it until Microsoft gets around to fixing these major brokennesses in IE. Otherwise you can browser detect and use that DirectX hack.
If you've got questions on how to get truecolor transparent PNGs to work in your own code, I could throw together some sample code. With this patch in and those workarounds, it's working great for me.
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