Struct WindowDesc 

pub struct WindowDesc<'a> {
    pub title: &'a str,
    pub app_id: &'a str,
    pub size: LogicalSize,
    pub constraints: SizeConstraints,
    pub mode: DisplayMode,
    pub resizable: bool,
    pub visible: bool,
    pub accept_drops: bool,
    pub role: WindowRole<'a>,
    pub transparent: bool,
}

Everything needed to create a window.

POD apart from the borrowed title, and Copy-free only because of it. The lifetime is deliberate: a shell never needs to own the string past the call, and forcing a String on every caller would allocate on a path that runs once.

Fields

title: &'a str

Title bar text. Also what the taskbar and window switcher show.

app_id: &'a str

Application identifier, e.g. "sh.kryptic.crcbl.sandbox".

Wayland’s xdg_toplevel.set_app_id and X11’s WM_CLASS. This is how a desktop environment matches a window to its .desktop file for the icon and the taskbar grouping, and getting it wrong is why some applications show a generic gear icon. There is no useful default, so it is required.

size: LogicalSize

Requested client-area size, in logical units.

A request, not a demand — a tiling window manager will size the window however it likes and the first ShellEvent::Resized is the authority. Never size a swapchain from this field.

constraints: SizeConstraints

Resize limits and aspect lock; see SizeConstraints.

mode: DisplayMode

Windowed or borderless at creation.

Setting it here rather than creating windowed and immediately switching avoids a visible flash of a decorated window, which is what every engine that gets this wrong looks like on startup.

resizable: bool

Whether the window is resizable at all.

Distinct from min == max in SizeConstraints: this also removes the maximize button and the resize handles, which is a different visual result even where the enforced size is identical.

visible: bool

Whether to map the window immediately.

false creates it hidden, so the first frame can be rendered before anything is shown — the fix for the black-window flash on startup. Reveal it with set_visible once there is something to look at.

accept_drops: bool

Whether files dropped on the window should produce ShellEvent::DroppedFile.

Off by default because accepting a drop means advertising it to the window system, and a game that ignores drops should not show a drop cursor.

role: WindowRole<'a>

What kind of window: an application window, a panel or a popup. See WindowRole.

transparent: bool

Whether the desktop shows through where the frame’s alpha is below one: a bar with no background, a launcher with rounded corners.

Asked for at creation because every window system decides it then — the visual, the swapchain, the window’s own background. A backend that cannot do it refuses the window (ShellCaps::TRANSPARENT) rather than draw it opaque. The frame’s alpha is premultiplied.

Trait Implementations

impl<'a> Clone for WindowDesc<'a>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Copy for WindowDesc<'a>

impl<'a> Debug for WindowDesc<'a>

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

Formats the value using the given formatter.

impl Default for WindowDesc<'_>

fn default() -> Self

Returns the “default value” for a type.