mapbox/mapbox-gl-js

When a character from custom font is not found.

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#12,975 opened on Nov 16, 2023

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Description

mapbox-gl-js/v2.1.1:

Question

I have set glyphs to my custom font url but there scenarios which are breaking the font when some character is not found. A character 〜 is not found and then mapbox tries to request from a different range from 0-255 -> some other range but that range does not exist in my font as i only have 0-255 range. How can i add a fallback that either it finds the 〜 and displays or it shows a ? instead of the characters which are not found.

Due to this my map style is breaking.

Contributor guide

Tech stack
javascript
Domain
frontend
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
needs maintainer response
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
knowledge of Mapbox GL JS glyph loading
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
The user requests a fallback for missing glyphs in custom fonts. Investigate glyph loading in Mapbox GL JS, particularly the logic that requests glyph ranges. Look at the source code for font handling (e.g., src/ui/map.js, src/style/style.js) to understand how missing characters are handled. The maintainers need to clarify if a fallback mechanism exists or can be added. Consider adding a configurable fallback font or a placeholder character. Check if similar issues exist or if there is a workaround.
When a character from custom font is not found. · mapbox/mapbox-gl-js#12975 | Good First Issue