Inspect LSB and RSB Simultaneously in FontForge

Inspecting both the left sidebearing (LSB) and right sidebearing (RSB) values at the same time in FontForge is essential for maintaining consistent spacing across your font. This guide explains how to view and evaluate both metrics simultaneously using the Metrics Window and the Glyph Info dialog, providing a streamlined workflow for spacing and kerning adjustments.

Using the Metrics Window

The Metrics Window is the most effective way to inspect and edit both sidebearings simultaneously alongside real-time visual previews.

  1. In the main Font View window, select the glyph or sequence of glyphs you want to inspect.
  2. Navigate to the top menu and select Metrics > Open Metrics Window (or press Ctrl + K on Windows/Linux, Cmd + K on macOS).
  3. Look at the data table directly below the graphical display area.
  4. Locate the text fields assigned to the active glyph:
    • LBearing: Displays the current Left Sidebearing value in font units.
    • RBearing: Displays the current Right Sidebearing value in font units.
    • Width: Displays the total advance width, which automatically correlates with your sidebearing values.
  5. You can view these figures simultaneously for any glyph currently loaded into the Metrics Window. Modifying either numerical field immediately updates the opposing value's visual position and the overall advance width.

Using the Glyph Info Window

If you only need to inspect exact numerical values for a single character without opening the visual metrics editor:

  1. Select the glyph in the Font View or open it in the Glyph Outline View.
  2. Go to Element > Glyph Info (or press Ctrl + I / Cmd + I).
  3. Select the Horizontal metrics tab from the left-hand panel.
  4. The window will display the Left Side Bearing, Right Side Bearing, and Width values together in a single static view for quick reference.