| # Renderer Host Input |
| |
| This directory contains browser side input event handling code. |
| |
| ## TouchpadPinchEventQueue |
| |
| In order for pages to override the behaviour of touchpad pinch zooming, we offer |
| synthetic wheel events that may be canceled. The `TouchpadPinchEventQueue` |
| accepts the gesture pinch events created from native events and sends the |
| appropriate wheel events to the renderer. Once the renderer has acknowledged a |
| wheel event, we offer the corresponding gesture pinch event back to the client |
| of the `TouchpadPinchEventQueue`. If the pinch has not been consumed by the page, |
| the client may go on to send the actual gesture pinch event to the renderer which |
| will perform the pinch zoom. |
| |
| Note that for touchscreen gesture pinch events, there is no need for a similar |
| queue as touch events would have already been offered to the renderer before |
| being recognized as a pinch gesture. |
| |
| See [issue 289887](https://crbug.com/289887) for the discussion on offering |
| wheel events for touchpad pinch. |
| |
| Touchpad pinch zoom [design doc](https://docs.google.com/document/d/1cYdt9r9stHLA2lbJ2I-Ucl_djhdSyngYFbmufZaLRHE/edit?usp=sharing). |
