Vito Chin has announced the release of a new image manipulation extension that was ported from Imagick - Gmagick.

The extension seeks to make the image processing capability of GraphicsMagick accessible from PHP. GraphicsMagick is forked from version 5.5.2 of ImageMagick and had since developed with important differences and improvements. [...] In terms of Gmagick and Imagick, we try to keep the method interface similar so existing Imagick users will find converting to Gmagick a breeze.

You can grab the extension from its PECL page.