Struct winit::dpi::LogicalPosition

source ·

pub struct LogicalPosition<P> {
    pub x: P,
    pub y: P,
}

Expand description

A position represented in logical pixels.

The position is stored as floats, so please be careful. Casting floats to integers truncates the fractional part, which can cause noticeable issues. To help with that, an Into<(i32, i32)> implementation is provided which does the rounding for you.

Fields§

§x: P§y: P

Implementations§

source §

impl LogicalPosition

source

pub const fn new(x: P, y: P) -> LogicalPosition

Examples found in repository ?

examples/child_window.rs (line 20)

fn main() -> Result<(), impl std::error::Error> {
    use std::collections::HashMap;

    use winit::dpi::{LogicalPosition, LogicalSize, Position};
    use winit::event::{ElementState, Event, KeyEvent, WindowEvent};
    use winit::event_loop::{ActiveEventLoop, EventLoop};
    use winit::raw_window_handle::HasRawWindowHandle;
    use winit::window::Window;

    #[path = "util/fill.rs"]
    mod fill;

    fn spawn_child_window(parent: &Window, event_loop: &ActiveEventLoop) -> Window {
        let parent = parent.raw_window_handle().unwrap();
        let mut window_attributes = Window::default_attributes()
            .with_title("child window")
            .with_inner_size(LogicalSize::new(200.0f32, 200.0f32))
            .with_position(Position::Logical(LogicalPosition::new(0.0, 0.0)))
            .with_visible(true);
        // `with_parent_window` is unsafe. Parent window must be a valid window.
        window_attributes = unsafe { window_attributes.with_parent_window(Some(parent)) };

        event_loop.create_window(window_attributes).unwrap()
    }

    let mut windows = HashMap::new();

    let event_loop: EventLoop<()> = EventLoop::new().unwrap();
    let mut parent_window_id = None;

    event_loop.run(move |event: Event<()>, event_loop| {
        match event {
            Event::Resumed => {
                let attributes = Window::default_attributes()
                    .with_title("parent window")
                    .with_position(Position::Logical(LogicalPosition::new(0.0, 0.0)))
                    .with_inner_size(LogicalSize::new(640.0f32, 480.0f32));
                let window = event_loop.create_window(attributes).unwrap();

                parent_window_id = Some(window.id());

                println!("Parent window id: {parent_window_id:?})");
                windows.insert(window.id(), window);
            },
            Event::WindowEvent { window_id, event } => match event {
                WindowEvent::CloseRequested => {
                    windows.clear();
                    event_loop.exit();
                },
                WindowEvent::CursorEntered { device_id: _ } => {
                    // On x11, println when the cursor entered in a window even if the child window
                    // is created by some key inputs.
                    // the child windows are always placed at (0, 0) with size (200, 200) in the
                    // parent window, so we also can see this log when we move
                    // the cursor around (200, 200) in parent window.
                    println!("cursor entered in the window {window_id:?}");
                },
                WindowEvent::KeyboardInput {
                    event: KeyEvent { state: ElementState::Pressed, .. },
                    ..
                } => {
                    let parent_window = windows.get(&parent_window_id.unwrap()).unwrap();
                    let child_window = spawn_child_window(parent_window, event_loop);
                    let child_id = child_window.id();
                    println!("Child window created with id: {child_id:?}");
                    windows.insert(child_id, child_window);
                },
                WindowEvent::RedrawRequested => {
                    if let Some(window) = windows.get(&window_id) {
                        fill::fill_window(window);
                    }
                },
                _ => (),
            },
            _ => (),
        }
    })
}