Struct bevy::window::Window

pub struct Window { /* private fields */ }

An operating system window that can present content and receive user input.

To create a window, use a EventWriter<CreateWindow>.

Window Sizes

There are three sizes associated with a window. The physical size which is the height and width in physical pixels on the monitor. The logical size which is the physical size scaled by an operating system provided factor to account for monitors with differing pixel densities or user preference. And the requested size, measured in logical pixels, which is the value submitted to the API when creating the window, or requesting that it be resized.

The actual size, in logical pixels, of the window may not match the requested size due to operating system limits on the window size, or the quantization of the logical size when converting the physical size to the logical size through the scaling factor.

Accessing a Window from a system

To access a Window from a system, use [bevy_ecs::change_detection::ResMut]<crate::Windows>.

Example

fn access_window_system(mut windows: ResMut<Windows>){
    for mut window in windows.iter_mut() {
        window.set_title(String::from("Yay, I'm a window!"));
    }
}

To test code that uses Windows, one can test it with varying Window parameters by creating WindowResizeConstraints or WindowDescriptor structures. values by setting

let resize_constraints = WindowResizeConstraints {
                            min_width: 400.0,
                            min_height: 300.0,
                            max_width: 1280.0,
                            max_height: 1024.0,
};
let window_descriptor = WindowDescriptor {
    width: 800.0,
    height: 600.0,
    resizable: true,
    resize_constraints,
    ..default()
};
let mut window = Window::new(
   WindowId::new(),
   &window_descriptor,
   100, // physical_width
   100, // physical_height
   1.0, // scale_factor
   None, None);

let area = compute_window_area(&window);
assert_eq!(area, 100.0 * 100.0);

grow_window_to_text_size(&mut window, "very long text that does not wrap");
assert_eq!(window.physical_width(), window.requested_width() as u32);
grow_window_to_text_size(&mut window, "very long text that does wrap, creating a maximum width window");
assert_eq!(window.physical_width(), window.requested_width() as u32);

set_new_title(&mut window, "new title".to_string());
let mut found_command = false;
for command in window.drain_commands() {
    if command == (WindowCommand::SetTitle{ title: "new title".to_string() }) {
        found_command = true;
        break;
    }
}
assert_eq!(found_command, true);
}

Implementations

impl Window

pub fn new(
    id: WindowId,
    window_descriptor: &WindowDescriptor,
    physical_width: u32,
    physical_height: u32,
    scale_factor: f64,
    position: Option<IVec2>,
    raw_handle: Option<RawHandleWrapper>
) -> Window

Creates a new Window.

pub fn id(&self) -> WindowId

Get the window’s WindowId.

pub fn width(&self) -> f32

The current logical width of the window’s client area.

pub fn height(&self) -> f32

The current logical height of the window’s client area.

pub fn requested_width(&self) -> f32

The requested window client area width in logical pixels from window creation or the last call to set_resolution.

This may differ from the actual width depending on OS size limits and the scaling factor for high DPI monitors.

pub fn requested_height(&self) -> f32

The requested window client area height in logical pixels from window creation or the last call to set_resolution.

This may differ from the actual width depending on OS size limits and the scaling factor for high DPI monitors.

pub fn physical_width(&self) -> u32

The window’s client area width in physical pixels.

pub fn physical_height(&self) -> u32

The window’s client area height in physical pixels.

pub fn resize_constraints(&self) -> WindowResizeConstraints

The window’s client resize constraint in logical pixels.

pub fn position(&self) -> Option<IVec2>

The window’s client position in physical pixels.

pub fn set_maximized(&mut self, maximized: bool)

Set whether or not the window is maximized.

pub fn set_minimized(&mut self, minimized: bool)

Sets the window to minimized or back.

Platform-specific

• iOS / Android / Web: Unsupported.
• Wayland: Un-minimize is unsupported.

pub fn set_position(&mut self, monitor: MonitorSelection, position: IVec2)

Sets the position of the window on the selected monitor in physical pixels.

This automatically un-maximizes the window if it’s maximized.

Platform-specific

• iOS: Can only be called on the main thread. Sets the top left coordinates of the window in the screen space coordinate system.
• Web: Sets the top-left coordinates relative to the viewport.
• Android / Wayland: Unsupported.

pub fn center_window(&mut self, monitor_selection: MonitorSelection)

Modifies the position of the window to be in the center of the current monitor

Platform-specific

• iOS: Can only be called on the main thread.
• Web / Android / Wayland: Unsupported.

pub fn set_resize_constraints(
    &mut self,
    resize_constraints: WindowResizeConstraints
)

Modifies the minimum and maximum window bounds for resizing in logical pixels.

pub fn set_resolution(&mut self, width: f32, height: f32)

Request the OS to resize the window such the client area matches the specified width and height.

pub fn set_scale_factor_override(&mut self, scale_factor: Option<f64>)

Override the os-reported scaling factor.

pub fn update_scale_factor_from_backend(&mut self, scale_factor: f64)

pub fn update_actual_size_from_backend(
    &mut self,
    physical_width: u32,
    physical_height: u32
)

pub fn update_actual_position_from_backend(&mut self, position: IVec2)

pub fn scale_factor(&self) -> f64

The ratio of physical pixels to logical pixels

physical_pixels = logical_pixels * scale_factor

pub fn backend_scale_factor(&self) -> f64

The window scale factor as reported by the window backend.

This value is unaffected by scale_factor_override.

pub fn scale_factor_override(&self) -> Option<f64>

The scale factor set with set_scale_factor_override.

This value may be different from the scale factor reported by the window backend.

pub fn title(&self) -> &str

Get the window’s title.

pub fn set_title(&mut self, title: String)

Set the window’s title.

pub fn present_mode(&self) -> PresentMode

Get the window’s PresentMode.

pub fn alpha_mode(&self) -> CompositeAlphaMode

Get the window’s CompositeAlphaMode.

pub fn set_present_mode(&mut self, present_mode: PresentMode)

Set the window’s PresentMode.

pub fn resizable(&self) -> bool

Get whether or not the window is resizable.

pub fn set_resizable(&mut self, resizable: bool)

Set whether or not the window is resizable.

pub fn decorations(&self) -> bool

Get whether or not decorations are enabled.

(Decorations are the minimize, maximize, and close buttons on desktop apps)

Platform-specific

iOS, Android, and the Web do not have decorations.

pub fn set_decorations(&mut self, decorations: bool)

Set whether or not decorations are enabled.

(Decorations are the minimize, maximize, and close buttons on desktop apps)

Platform-specific

iOS, Android, and the Web do not have decorations.

pub fn cursor_grab_mode(&self) -> CursorGrabMode

Get whether or how the cursor is grabbed.

Platform-specific

• Windows doesn’t support CursorGrabMode::Locked
• macOS doesn’t support CursorGrabMode::Confined
• iOS/Android don’t have cursors.

Since Windows and macOS have different CursorGrabMode support, it’s possible the value returned here is not the same as the one actually sent to winit.

pub fn set_cursor_grab_mode(&mut self, grab_mode: CursorGrabMode)

Set whether and how the cursor is grabbed.

This doesn’t hide the cursor. For that, use set_cursor_visibility

Platform-specific

• Windows doesn’t support CursorGrabMode::Locked
• macOS doesn’t support CursorGrabMode::Confined
• iOS/Android don’t have cursors.

Since Windows and macOS have different CursorGrabMode support, we first try to set the grab mode that was asked for. If it doesn’t work then use the alternate grab mode.

pub fn cursor_visible(&self) -> bool

Get whether or not the cursor is visible.

Platform-specific

• Windows, X11, and Wayland: The cursor is hidden only when inside the window. To stop the cursor from leaving the window, use set_cursor_grab_mode.
• macOS: The cursor is hidden only when the window is focused.
• iOS and Android do not have cursors

pub fn set_cursor_visibility(&mut self, visible_mode: bool)

Set whether or not the cursor is visible.

Platform-specific

• Windows, X11, and Wayland: The cursor is hidden only when inside the window. To stop the cursor from leaving the window, use set_cursor_grab_mode.
• macOS: The cursor is hidden only when the window is focused.
• iOS and Android do not have cursors

pub fn cursor_icon(&self) -> CursorIcon

Get the current CursorIcon

pub fn set_cursor_icon(&mut self, icon: CursorIcon)

Set the CursorIcon

pub fn physical_cursor_position(&self) -> Option<DVec2>

The current mouse position, in physical pixels.

pub fn cursor_position(&self) -> Option<Vec2>

The current mouse position, in logical pixels, taking into account the screen scale factor.

pub fn set_cursor_position(&mut self, position: Vec2)

Set the cursor’s position

pub fn update_focused_status_from_backend(&mut self, focused: bool)

pub fn update_cursor_physical_position_from_backend(
    &mut self,
    cursor_position: Option<DVec2>
)

pub fn mode(&self) -> WindowMode

Get the window’s WindowMode

pub fn set_mode(&mut self, mode: WindowMode)

Set the window’s WindowMode

pub fn close(&mut self)

Close the operating system window corresponding to this Window.

This will also lead to this Window being removed from the Windows resource.

If the default WindowPlugin is used, when no windows are open, the app will exit. To disable this behaviour, set exit_on_all_closed on the WindowPlugin to false

pub fn drain_commands(&mut self) -> impl Iterator<Item = WindowCommand>

pub fn is_focused(&self) -> bool

Get whether or not the window has focus.

A window loses focus when the user switches to another window, and regains focus when the user uses the window again

pub fn raw_handle(&self) -> Option<RawHandleWrapper>

Get the RawHandleWrapper corresponding to this window if set.

During normal use, this can be safely unwrapped; the value should only be None when synthetically constructed for tests.

pub fn canvas(&self) -> Option<&str>

The “html canvas” element selector.

If set, this selector will be used to find a matching html canvas element, rather than creating a new one. Uses the CSS selector format.

This value has no effect on non-web platforms.

pub fn fit_canvas_to_parent(&self) -> bool

Whether or not to fit the canvas element’s size to its parent element’s size.

Warning: this will not behave as expected for parents that set their size according to the size of their children. This creates a “feedback loop” that will result in the canvas growing on each resize. When using this feature, ensure the parent’s size is not affected by its children.

This value has no effect on non-web platforms.

Trait Implementations

impl Debug for Window

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.