#39273 [Bgs]: imagecopyresized() not compatable with alpha channel

ID: 39273 User updated by: seth at pricepages dot org Reported By: seth at pricepages dot org Status: Bogus Bug Type: GD related Operating System: Mac 10.4 PHP Version: 5.1.6 Assigned To: pajoye New Comment: translucide (French) = translucent (English) Sorry, that confused me for a bit. "Boolean transparency" means that the pixel is either fully transparent, or fully opaque. Never partially transparent. The area outside of the line is fine, it should be transparent and it is in your image. This is correct. What is suffering from "boolean transparency" are the edges of the line. For example: In your example script, one alpha value was 63, and the other was 127. In your output PNG, those values have been changed to 0 and 127. I should mention that if you are using Microsoft's Internet Explorer version 6 or less, a PNG image will display with boolean transparency due to a bug in the browser. So you won't be able to see the difference. Use FireFox. Previous Comments: ------------------------------------------------------------------------ [2006-10-28 14:19:46] pajoye@php.net Pardon? What is a boolean transparency? Please understand these three things: - The transparent color is one *color*, an index for palette based image or 32bits value for truecolor images. It defines which color is used as the *background* color (like white is the background color of a white paper). - The *alpha* channel of a pixel defines how translucide the pixel has to be. It has nothing to do with the transparent color. - Your image has *no* transparent color but many pixels with various *alpha* levels. Load the result images in your favourite paint programs to see what I mean. The area outside the line is translucide, it is due to the alpha channel. ------------------------------------------------------------------------ [2006-10-28 14:11:56] seth at pricepages dot org But that has one of the bugs that I pointed out: boolean transparency. The original doesn't have that problem. ------------------------------------------------------------------------ [2006-10-28 14:04:59] pajoye@php.net Use the code I just gave you, it does create the resized version (by copying): http://blog.thepimp.net/misc/39273_out.png ------------------------------------------------------------------------ [2006-10-28 13:15:45] seth at pricepages dot org I ran your code before I posted my last comment, but I still don't know what you are implying. The results are exactly as I expect them to be. If this bug is bogus, please tell me how I can create an enlarged version of test.png? It isn't possible without applying a fix. ------------------------------------------------------------------------ [2006-10-28 10:49:54] pajoye@php.net "I am aware that the image is fully black, except for variations in alpha. That is why this is a bug related to the alpha channel and not any other." You are not aware that your image is *NOT* fully black. Background color (the transparent color) is not the same than a color with a ALPHA component. Please run the code I gave you, read the results (like the values of the channels in these two pixels, or any other). ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/39273 -- Edit this bug report at http://bugs.php.net/?id=39273&edit=1