Disable smart zoom on macOS

[dtarkows]

On macOS, if the user double taps with two fingers, it initiates a zoom which seems to be context dependent on the element that was clicked on.

Is there a way to disable this from within CEF?

[magreenblatt]

Can it be disabled in Google Chrome?

[dtarkows]

I can't find a way to explicitly disable it in Chrome or Chromium.

Upon further investigation, I've determined that the Cocoa event that causes this behavior is "smartMagnify". It looks like Chromium maps this to the GestureDoubleTap event with a tap count of 1. The GestureDoubleTap event is what handles the (single finger) double tap on Android. I can't determine if there is any way to enable or disable specific gesture events.

[Czarek]

This can be disabled in Chromium in Browser::PreHandleGestureEvent:
https://cs.chromium.org/chromium/src/ch ... bad3bf8ef9

With such code:

Code: Select all

if (event.GetType() == blink::WebInputEvent::kGestureDoubleTap) {
    return true;
}


Is it possible to expose such callback in CEF?

Does anyone know if it is possible to intercept and block the NSEventTypeSmartMagnify / smartMagnifyWithEvent events, so that they are not forwarded to Chromium?

Ref:
1. Old code that disabled double tap in PDF viewer: https://chromium-review.googlesource.co ... /+/614084/
2. Double tap disabled in Extensions: https://cs.chromium.org/chromium/src/ex ... bad3bf8ef9
3. NSEventTypeSmartMagnify event handled in Chromium: https://cs.chromium.org/chromium/src/co ... bad3bf8ef9
4. smartMagnifyWithEvent event handled in Chromium: https://cs.chromium.org/chromium/src/co ... bad3bf8ef9
5. Double tap to zoom enabled in Chromium via this issue: https://bugs.chromium.org/p/chromium/is ... ?id=452592

[Czarek]

In Electron smart zoom can be disabled by calling WebFrame::SetVisualZoomLevelLimits. There is no such equivalent in CEF API.

Ref:
1. https://electronjs.org/docs/api/web-fra ... ximumlevel
2. https://github.com/MarshallOfSound/Goog ... 2793/files