Path tangents and normals

Note: The plugins work for Gimp2. They do not work for Gimp3 unless somebody ports them to Gimp3.

Three Gimp plugins to draw tangents or normals to paths. To get the plugins, do:

1. At the bottom of this page there is the Download button. Clicking it you get one .ZIP file. Unzip it and put the python file it contains in your Gimp's plug-ins folder and restart Gimp.
2. This registers in your Gimp the plugins
• Bounding box
• Common tangent or normal between two paths
  
• Parallel tangents or normals
  
• Tangents or normals from a point
• Tangents or normals from a stroke end of another path
  
3. To find the plugins in Gimp, go to the Paths tab and right-click the path you are going to crop or slice. This opens a pop-up window. At the bottom follow the link Tools > Tangents and normals > ...  and choose.
   

Some helping words:

• Bounding box does what the name says.
• Common tangent or normal between two paths takes as input three paths:
  • The active path (the right-clicked path).  This is one of the two paths for which a common tangent or normal will be made.
  • Another path.  This is the other one of the two paths.
  • The tentative tangent or normal. A path with two anchors. This is a user-provided guess (approximation) of the desired tangent or normal
  The plugin draws one tangent or normal between the two paths, or, depending of the user inputs, a line segment which is a tangent of one and a normal of the other path.
• Parallel tangents or normals requires two input paths:
  • The active path (the right-clicked path).  This is the path to which the tangent or normal will be created.
  • The tentative tangent or normal. A path with two anchors. This is a user-provided guess (approximation) of the desired tangent or normal
  The plugin draws tangents or normals of the path, all parallel to to the tentative one. They are created as new paths. There are three modes of action:
• Draw only the closest (default): Draw only the closest (minimal snapping movement).
• Draw all for the closest stroke: Draw all possible tangents or normals  but only for the closest stroke of the path.
• Draw all: Draw all possible tangents or normals  for the whole path.
• Tangents or normals from a point takes two input paths:
  • The active path (the right-clicked path).  This is the path to which the tangent or normal will be created.
  • The tentative line. A path with two anchors. This is a user-provided guess (approximation) of the desired tangent or normal
  The plugin draws tangents or normals of the path, each starting at one end of the tentative line and its other end "snapped"  to a tangent or normal of the path. There are the same three modes of action as above.
• Tangents or normals from a stroke end of another path takes three input paths:
  • The active path (the right-clicked path).  This is the path to which the tangent or normal will be created.
  • Another path. The tangent will be drawn starting at an end of a stroke of this path.
  • The tentative line. A path with two anchors. This is a user-provided guess (approximation) of the desired tangent or normal.
  The plugin draws tangents or normals of the active path,  "snapping" each end of the tentative line: one end to the closest stroke end of the other path, and the other end to a tangent or normal of the active path. There are the same three modes of action as above.

Some explanations and pictures appear at www.gimp-forum.net.

Download