* Closes https://github.com/emilk/egui/issues/7120
You can now zoom only the X axis by holding down shift, and zoom only
the Y axis by holding down ALT.
In summary
* `Shift`: horizontal
* `Alt`: vertical
* `Ctrl`: zoom (`Cmd` on Mac)
Thus follows:
* `scroll`: pan both axis (at least for trackpads and mice with two-axis
scroll)
* `Shift + scroll`: pan only horizontal axis
* `Alt + scroll`: pan only vertical axis
* `Ctrl + scroll`: zoom all axes
* `Ctrl + Shift + scroll`: zoom only horizontal axis
* `Ctrl + Alt + scroll`: zoom only vertical axis
This is provided the application uses `zoom_delta_2d` for its zooming
needs.
The modifiers are exposed in `InputOptions`, but it is strongly
recommended that you do not change them.
## Testing
Unfortunately we have no nice way of testing this in egui.
But I've tested it in `egui_plot`.
53098fad7b