Variations on Gimp's Perspective Transform tool:
different user interfaces. These plugins work on the active layer.
Currently there are three plugins. To get them, do:

- At the bottom of this page there is a Download button. Clicking you get one .ZIP file. Unzip it and put the python file it contains in your Gimp's plug-ins folder and restart Gimp.
- This registers in your Gimp the plugins.
- The place of the plugins in Gimp's menu is
__Filters>Distorts>Perspective transform>...__For an example and more detailed explanations, see www.gimp-forum.net.

**Perspective transform - 4 points to 4 points**takes as input two paths, the Source and the Target, each having 4 anchors. The transformation is the one which sends the anchors of the Source onto the anchors of the Target, and distorting the whole picture accordingly.**Perspective transform - 4 points to circle (clock face)**is designed to correct a distorted circle (an ellipse) to a true circle. It takes as input one path, the Source, having 4 anchors (meant to be 4 points on the distorted circle), and a list of 4 hours on an imaginary clock face. It sends the 4 anchors of the Source to corresponding hours on a circle.**Perspective transform - 4 points to rectangle corners**is designed to correct quadrangles to rectangles. It takes as input one path, the Source, having 4 anchors. The Target is a rectangle with sides horizontal and vertical; the user can choose between three alternatives (the default is automatic requiring no input from the user). The region inside the Source path will be mapped onto the Target rectangle, the anchors going to the corners.**Perspective transform - 2+2+2 points to circle (3 diameters)**is designed to correct a distorted circle (an ellipse) to a true circle. The main input is three paths, each with two anchors, each showing one would-be diameter of the circle. The diameters have end points on the distorted circle and they pass through the point that should become the center of the circle. A fourth input path is used to determine direction (rotation) of the resulting picture.**Perspective transform - 1+2+3 points to circle (center and 2+3 points)**is designed to correct a distorted circle (an ellipse) to a true circle. As input it takes one path with three strokes, one with 1 anchor, one with 2 anchor, and one with 3 anchors. The 1-anchor path has as its sole anchor that point which should become the center of the corrected circle. The 2-anchors path has as its anchors two points on the distorted circle (and they are also used to determine to which position the resulting circle should be rotated). The 3-anchors path has as its anchors three other points on the distorted circle.