PHP - 从blob文件创建图像并与其他文件结合，同时保持透明度

Question

Im trying to combine an image I create from a blob I pull from my database with another I create on the fly thats transparent. My reason for doing this is because I need the image dimensions to be within the power of two so I can use them as textures in opengl. Im kind of at a loss on how to place the blob image within the one I create on the fly exactly where I want it. Not only that but when I create the image from the blob it occasionally leaves any black spots transparent which definitely sucks.

So how can I create an image from a blob file and combine it with another while maintaining transparency. Im using the gd library by the way.

Answer 1

There's imagecreatefromstring(), so you'd simply have

$img = imagecreatefromstring($blob);

and then use $img as you would any other picture that'd you loaded from imagecreatefromjpeg/gif/png. The string version is actually somewhat intelligent and will try to figure out what type of picture you've got in the string, unlike the quite stupid imagecreatefromSOMETHING() versions, which have no brains whatsoever.