Understanding the Background Layer in FontForge

In FontForge's glyph editing window, the background layer serves as a non-rendering reference and drafting workspace. Unlike the foreground layer, any artwork, vector paths, or imported images placed in the background layer are completely excluded from the final compiled font file. This makes it an essential tool for type designers to store source sketches, retain alternate path iterations, and trace reference graphics without altering the final glyph outlines.

Purpose and Functionality

The background layer functions primarily as a design guide and scratchpad. When developing type, you rarely begin with final Bézier curves directly in the exportable space. The background layer allows you to import external assets—such as bitmap scans of hand-drawn lettering, PNGs, or raw SVGs—directly behind the main drafting canvas. You can then use FontForge’s vector drawing tools to manually trace over these references in the foreground layer, or run FontForge’s autotrace feature to generate curves based on the background image.

Vector Storage and Iteration

Beyond holding raster images, the background layer can hold standard vector paths. Designers frequently use it to:

  • Save In-Progress Iterations: Before applying destructive operations (such as overlap removal, boolean operations, or rounding coordinates), you can copy your current foreground paths into the background as a safe, local backup.
  • Keep Construction Geometry: Circles, diagonal stems, and alignment vectors used to measure angles or proportions can reside in the background without generating validation errors during font generation.
  • Compare Font Weights: You can paste an outline from a regular weight into the background of a bold glyph to visually evaluate stroke expansion and balance.

FontForge organizes glyph drawing into distinct planes visible in the Layers palette:

  • Foreground: The active layer containing the printable contours and hints that will be written into the generated font file (OTF, TTF, etc.).
  • Background: The inactive, non-printing layer used solely for tracing, drafts, and reference materials.
  • Guide: The global and local alignment lines (baselines, x-height, ascenders) shared across glyphs.

To work with the background layer, select it in the floating Layers palette or use the menu bar via View > Layers > Background. Once active, imported images or pasted vectors will sit on this plane. You can toggle the visibility of the background layer on or off, adjust its opacity, or swap content directly between the foreground and background layers using the Edit > Copy to Background or Point > Make Parallel operations.