How to Flip a Glyph in FontForge

Flipping a glyph horizontally or vertically in FontForge allows font designers to quickly create mirrored shapes, adjust directional components, or build symmetrical character sets. This guide explains how to use FontForge's built-in transformation tools to invert glyph outlines, correct path directions, and adjust character metrics properly.

Method 1: Using the Transform Dialog

  1. Open the Glyph: Double-click the glyph you want to modify in the Font Window to open the Glyph Editing Window.
  2. Select the Outlines: Press Ctrl + A (Windows/Linux) or Cmd + A (macOS) to select all the contours you want to flip. You can also select specific paths using the Pointer tool.
  3. Open Transform: Navigate to the top menu and select Element > Transform > Transform... (or press Ctrl + \ / Cmd + \).
  4. Configure the Flip:
    • In the Transform dialog box, click the dropdown menu currently set to "Move" or "Scale" and choose either Flip Horizontally or Flip Vertically.
    • Choose the point of origin for the flip from the secondary dropdown:
      • Center of Selection: Flips the outlines directly in place based on their geometric center.
      • Glyph Origin: Flips across the base origin point (0,0 coordinate).
  5. Apply: Click OK to apply the transformation.

Method 2: Flipping Multiple Glyphs from the Font Window

To flip multiple glyphs at once:

  1. In the main Font Window, hold Shift or Ctrl/Cmd to select the glyph slots you want to flip.
  2. Select Element > Transform > Transform... from the menu.
  3. Set the action to Flip Horizontally or Flip Vertically.
  4. Set the origin to Glyph Origin or Center of Selection, depending on whether you want each glyph flipped in place or mirrored relative to the font axis.
  5. Click OK.

Important Post-Flip Adjustments

  • Correct Direction: Flipping a contour reverses its direction, turning clockwise paths into counter-clockwise paths and vice versa. This can cause rendering issues or inverted fills. After flipping, immediately go to Element > Correct Direction (or press Ctrl + Shift + D / Cmd + Shift + D) to automatically restore proper winding rules.
  • Adjust Side Bearings: Horizontal flips invert the Left Side Bearing (LSB) and Right Side Bearing (RSB). Switch to the Metrics Window (Metrics > New Metrics Window) to verify that the spacing and margins align correctly with the rest of your typeface.