This is a plugin for the Glyphs font editor. It is based on Show Smooth Node Angle and Proportion by harbortype.

One of the most common problems when designing multiple master and variable fonts is kinks. They happen when you have three points in a line that have different angles between masters AND have different proportions between points show as a ratio. If all of the above is true, you will get kinks in interpolations. (Read this tutorial for more info.)

This reporter plugin will highlight the nodes that may produce kinks in yellow. When you select it, it will tell you the angle between the handles and the ratio. If any one of the values match the other masters (becoming light gray), a kink will not happen.

The labels will have different colors depending on what’s happening on the other masters:

I baked a small tolerance of 1° for the angles and 1% for the proportions into the code, as it is very difficult to exactly match angles and handle lengths on a grid. If you believe these values do not produce a satisfactory result, please let me know.

1. Download the complete ZIP file and unpack it, or clone the repository.
2. Double click the .glyphsReporter file. Confirm the dialog that appears in Glyphs.
3. Restart Glyphs

• Add drawing aids to make the adjustment process easier (maybe showing the other master’s corresponding nodes in the background).
• Improve the positioning of the labels.