How to Fix GameMaker Camera Letterboxing Wrong on Window Resize

If resizing your GameMaker window stretches the game or misplaces the black bars, the port is not being re-fit. Recomputing it on resize fixes it. Here is how.

How to fix it

1. Detect the resize

In a controller's Step or an async event, compare window_get_width()/height() to the last known size and re-fit only when it changes.

2. Preserve the view aspect

Compute a scale that fits the view's aspect inside the window, then set the application surface and GUI to that size so the game scales uniformly.

3. Center for correct bars

Position the scaled surface centered in the window so the leftover space becomes even letterbox or pillarbox bars rather than offset to one side.

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 GameMaker 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.