[V3] SetZoom(0.5) , scaling ratio is less than 1

[sdlp9]

I want to implement automatic scaling of the window size according to the current ratio, but when the scaling ratio is less than 1, there is a problem with dragging the edges of the window. The parts that shrink inward can also be dragged.

Recording.2025-09-20.105123.mp4

[dosubot]

Hi @sdlp9! I'm Dosu and I’m helping the wails team.

This issue happens because SetZoom scales the window's visual content, but the OS-level regions for edge dragging (resizing) aren't updated to match the new scale. So, when the ratio is less than 1, you can drag edges inside the shrunken area—this is a mismatch between the scaled UI and the native input hit zones. There isn't an official workaround or built-in fix for this in Wails v3 yet, and no documentation or tickets directly address it.

If you're using frameless windows, Wails relies on custom frontend resize zones and event handling for resizing, so you may need to implement your own logic for correct edge dragging. For native windows, fixing this would likely require platform-specific code to recalculate input regions after scaling—on Windows, for example, this involves handling WM_NCHITTEST and adjusting hit testing to account for the zoom factor, but this is non-trivial and not currently supported out of the box (related discussion).

The maintainers are aware of the need for better hit testing and window control support, so it's worth keeping an eye on future updates and issues for improvements (frameless resize context). If you want to explore workarounds, you could look into custom resize logic in your frontend or experiment with platform-specific hooks, but there is no ready-made solution at this time.

To reply, just mention @dosu.

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[EddieHuang-01]

same here, but no info found about how to customize 'resize zones' in frontend, is it done with a simple css property like --wails-draggable: drag;, or do we have to implement the whole resizing logic by ourselves ? @dosu

[aaadotpm]

Additional observations on macOS 26 (Tahoe)

I'm experiencing a related issue on macOS 26.2 (Tahoe) with Wails v3.0.0-alpha.64.

Symptoms

When using the View menu's Zoom In/Out (either via AddRole(application.ZoomIn) or custom menu items calling window.ZoomIn()), the entire webview frame scales instead of just the content inside. This creates large gray/empty areas around the shrunken content.

Expected behavior

Like Safari, only the web content should zoom while the window frame stays the same size. The content should be scrollable when zoomed in past the viewport.

Tested approaches (all exhibit the same behavior):

1. Wails built-in menu roles (application.ZoomIn, application.ZoomOut, application.ResetZoom)
2. Custom menu items calling window.ZoomIn() / window.ZoomOut() / window.ZoomReset()
3. Direct native code setting WKWebView.magnification via cgo

Environment

• macOS 26.2 (Tahoe)
• Apple Silicon (arm64)
• Wails v3.0.0-alpha.64
• Go 1.25.5

This appears to be a regression or compatibility issue with macOS 26's handling of WKWebView magnification.

[leaanthony]

🤖 Triage note: Cannot determine platform from the issue description alone. Could you confirm which OS this was reproduced on? Proposed labels once confirmed: Windows or MacOS or Linux.