iOS safe area

[frederik-uni]

Before:

After:

[emilk]

I think this should be part of eframe, i.e. so you can call eframe::safe_area_top(ctx) to get how many ui points from the top it is safe to put widgets.

[frederik-uni]

@emilk so, I move the safe area insets function to eframe, but what about the safe area widget. I think it would be better to use something like this instead of a widget:

fn safe_area<R>(ui: &mut Ui, inner: impl FnOnce(&mut Ui) -> R) -> R {
    let insets = get_ios_safe_area_insets();
    if let Some(insets) = insets {
        let cursor = ui.cursor().min;
        /*
        let x = insets.left - cursor.x as f64;
        if x > 0. {
            let (id, rect) = ui.allocate_space(vec2(x as f32, ui.available_height()));
            ui.interact(rect, id, Sense::hover());
        }
        */
        let y = insets.top - cursor.y as f64;
        if y > 0. {
            let (id, rect) = ui.allocate_space(vec2(ui.available_width(), y as f32));
            ui.interact(rect, id, Sense::hover());
        }
        let max_height = ui.available_height() - insets.bottom as f32;
        if max_height > 0.0 {
            ui.set_max_height(max_height);
        }
        let max_width = ui.available_width() - insets.right as f32;
        if max_width > 0.0 {
            ui.set_max_width(max_width);
        }
    }
    inner(ui)
}

where should I put it? should this be part of egui/egui_extras. should this & the safe area insets function be hidden behind a feature or should it be enabled for every iOS build? its kinda essential and probably needed in every iOS build anyway. And this example above will not work when the inset is != 0 on the left. do you have any ideas how I could get this to work properly?

Something like this would be great ui.within(rect, |ui| {});

[emilk]

One approach would be to modify FrameState::available_rect so that is is the safe area. That would mean egui::CentralPanel (and other panels) would start within that smaller rect. However, one should still paint some sort of background color outside that.

[lucasmerlin]

Seems like winit will soon have a safe area api: rust-windowing/winit#3890
Maybe we can use that one instead? Then other platforms will also be supported once support is added to winit (rust-windowing/winit#3910)