Hi all,

I'm doing a simple overlay of a transparent PNG onto a solid background. 'imagecopyresized' does the trick transparency-wise, but obviously the overlaid image is jagged. When using 'imagecopyresampled', everything is smooth but images with transparent backgrounds get a weird noise where the transparency should be. Any ideas? Here comes the code and an example:

 

// Preview image functions

			// 6a. Generate the preview image background (590x520)
			$tshirtbackgroundimage = imagecreatefrompng("./shirttemplate.png");
			$shirtimagepreview = imagecreatetruecolor(590,520);
				imagealphablending($shirtimagepreview, false);
				imagesavealpha($shirtimagepreview,true);
				$transparent = imagecolorallocatealpha($shirtimagepreview, 255, 255, 255, 127);
				imagefilledrectangle($shirtimagepreview, 0, 0, 590, 520, $transparent);
					imagecopyresampled($shirtimagepreview, $tshirtbackgroundimage, 0, 0, 0, 0, 590, 520, 590, 520);
					imagealphablending($shirtimagepreview, true);



			//6b. Resize the original image
			$newimageheightpreview = 280 * ($uploadedfileheight / $uploadedfilewidth);
			$shirtimagepreviewfront = imagecreatetruecolor(280,$newimageheightpreview);

				imagealphablending($shirtimagepreviewfront, false);
				imagesavealpha($shirtimagepreviewfront,true);
				$transparent = imagecolorallocatealpha($shirtimagepreviewfront, 255, 255, 255, 127);
				imagefilledrectangle($shirtimagepreviewfront, 0, 0, 280, $newimageheightpreview, $transparent);
					imagecopyresampled($shirtimagepreviewfront, $uploadedimage, 0, 0, 0, 0, 280, $newimageheightpreview, $uploadedfilewidth, $uploadedfileheight);


			// 6c. copy one to the other
			imagecopy($shirtimagepreview,$shirtimagepreviewfront,155,105,0,0,280,$newimageheightpreview);

 

 

Also, it's too late to back out of GD for this project, but does anyone have any heartfelt recommendations for another image library to use with php?

Thanks!

http://php.net/manual/en/function.imagesavealpha.php

ImageSaveAlpha:

 

Thanks for the suggestion—am I using imagesavealpha in completely the wrong way?! I've tried every combination of true and false for imagesavealpha and imagealphablending, but anything other than what I have causes one or both of the images' backgrounds to be drawn black. The only thing I can think is that I have a complete misconception about how one of the functions works, as everything looks as it should to me! Cheers.