GraphiteEditor/Graphite

Bug: Offset while using brush tool on iPad

Open

#3286 opened on Oct 14, 2025

View on GitHub
 (11 comments) (0 reactions) (0 assignees)Rust (25,662 stars) (1,176 forks)batch import
Good First Issue

Description

Description

  • Large offset while using the web version on iPad.
  • Using the apple pencil to draw with the brush tool on the iPad surface, there is a large noticable offset of the ink appearing from the tip of the pencil touching the screen.
  • The brush ink also flows outside of the artboard (although I suspect this might be by desgin)

Video Demonstration

https://drive.google.com/file/d/1buYIvX035Be9K-pn0Rn7eCGvYZ4jJTX1/view?usp=sharing

Other details

  • Safari version: 26
  • iOS version: iPadOS 26.0
  • iPad model: iPad Pro 13 inch, 2024

Preliminary thoughts

Contributor guide

Tech stack
rustwasmhtmlcss
Domain
frontend
Issue type
bug
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.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
RustCoordinate geometryTouch events
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate the coordinate transformation chain from touch input to canvas coordinates in the brush tool.rs file (editor/src/messages/tool/tool messages/brush tool.rs). Check if the offset is due to device pixel ratio mismatch or coordinate origin differences. Refer to the preliminary thoughts in the issue for clues. Test with iPad Safari to reproduce and compare coordinates.