How to Fix Sprite Atlas Edge Bleeding From Sub-Pixel drawImage on HTML5 Canvas

On an HTML5 canvas, sprites cut from an atlas show a thin edge of the neighboring sprite. The 2D context is smoothing across the atlas at fractional coordinates.

How to fix it

1. Disable image smoothing

Set ctx.imageSmoothingEnabled = false for pixel art so drawImage does not interpolate atlas texels across frame boundaries.

2. Add a gutter and use integer source rects

Pack the atlas with 1-2 px of padding and pass integer source x/y/width/height to drawImage so the sample never reaches the next frame.

3. Round destination positions

Wrap destination coordinates in Math.round() (or floor) so the draw lands on whole device pixels instead of straddling two.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every HTML5 error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.