FontForge Black Square Next to Glyph Explained

When working in FontForge, seeing a small black square icon next to or inside a glyph cell typically indicates that the glyph has been modified and contains unsaved changes. This article explains the primary function of this visual marker, why it renders as a solid square in certain interfaces, how it affects your font project, and how to manage or clear it.

The Modified Glyph Indicator

In FontForge’s main Font View window, each cell displays a character alongside its encoding and name. Whenever you edit a glyph—whether by moving points, altering the advance width, modifying bearings, or editing metadata—FontForge flags that character to track your edits.

This status marker is placed in the upper corner of the glyph cell. It serves as an alert that the current state of the glyph differs from the version saved on your drive. If you close the program without saving, any glyphs displaying this indicator will lose their recent alterations.

Why It Appears as a Black Square

Depending on the operating system, UI theme, and screen resolution, FontForge renders status indicators differently:

  • Rendering Variations: In classic X11 rendering, the modified indicator was designed as a small "x" or cross. On modern systems, GTK-based builds, and high-DPI displays, the drawing routine often scales this pixel mark into a small, solid black square.
  • Bitmap or View Settings: In some FontForge display configurations, toggling visual aids under the View menu can render small square markers to denote specific properties, but an individual mark appearing only on edited glyphs corresponds to the modification flag.

How to Clear the Marker

To remove the black square indicator from a glyph cell:

  1. Save Your Changes: Save the font as a native FontForge database file by selecting File > Save (or pressing Ctrl + S / Cmd + S). Once the .sfd file updates on disk, all modification markers will automatically vanish.
  2. Revert Undesired Changes: If you edited a glyph unintentionally and want to discard the changes, select the glyph cell and navigate to Edit > Revert Glyph. This restores the glyph to its last saved condition and removes the mark.

Other Possible Causes

While unsaved changes are the most common explanation, there are two alternate scenarios:

  • Glyph Color Tags: FontForge allows manual color-coding of glyphs for project organization via Glyph > Color. If a dark or black tag was manually assigned, a square swatch will show in the cell. You can remove it by selecting the glyph and choosing Glyph > Color > None.
  • Embedded Bitmap Strikes: If your font project contains embedded bitmap strikes (bdf/sbit data) alongside vector outlines, FontForge may display small square indicators denoting that bitmap data exists for that specific glyph slot under certain view configurations.