How to rotate an image in GD Image Library while keeping transparency?

Question

I\'m making a skin previewer for my site; I need to rotate parts of an image to create a representation of this for my users to see.

The skin is a PNG file, and all part

Answer 1

1. Cut out the piece of the image you want to rotate
2. Rotate preserving alpha using something like this http://www.exorithm.com/algorithm/view/rotate_image_alpha
3. Merge back in preserving alpha using the following:

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imagesetbrush($destimg, $srcimg);
// x, y are the center of target paste location
imageline($destimg, $x, $y, $x, $y, IMG_COLOR_BRUSHED);

Answer 2

You may want to check here for some uses for libpng (which will need zlib). If you are on linux you can write something in perl. CPAN GD module might be your ticket.

Answer 3

I use that to rotate a PNG and preserve transparency color. Works like a charm. It's "basic GD".

 $rotation = 135;
 $handle_rotated = imagerotate($handle_not_rotated,$rotation,0);
 imagealphablending($handle_rotated, true);
 imagesavealpha($handle_rotated, true); 

Don't know if it's what you're looking for?