enum ScreenCapture

Swift

enum ScreenCapture

A picture of the whole screen, for the one app that needs one.

Not the same question as ScreenshotBridge, which answers "what does this window look like" and exists for the agent. This is the desktop: every window on it, foreign and Lava alike, and the wallpaper behind them — which only the compositor can see, and which a client can therefore only ask for.

Nil in a windowed build. An app that cannot get one should say so rather than show an empty editor: there is nothing it can do about it, and pretending otherwise wastes the user's time finding that out.

Sources/LavaUI/ScreenCapture.swift:14

Properties

static var isAvailable: Bool { get }

Whether the desktop can be captured here at all.

Sources/LavaUI/ScreenCapture.swift:34

nonisolated(unsafe) static var provider: Provider?

Not documented.

Sources/LavaUI/ScreenCapture.swift:31

Methods

static func screen(includeSelf: Bool = false, x: Int32 = 0, y: Int32 = 0, w: Int32 = 0, h: Int32 = 0, maxSide: Int32 = 0) -> String?

The screen the pointer is on, as a PNG file.

includeSelf false leaves the calling window out — which is what a screenshot tool wants and cannot arrange for itself, since by the time it can ask, its own window is already up.

The crop is in framebuffer pixels; an empty one means the whole screen. It happens on the far side because a client has no codec of its own: a region of a PNG is not something it can take for itself.

Synchronous, and it costs an offscreen composite of the whole screen plus a PNG encode — once, when the user asks for a shot, never in a paint closure.

Sources/LavaUI/ScreenCapture.swift:49

Type aliases

typealias Provider = @Sendable (_ includeSelf: Bool, _ x: Int32, _ y: Int32, _ w: Int32, _ h: Int32, _ maxSide: Int32) -> String?

The path of a PNG the host wrote, or nil if it has no desktop to photograph.

A path rather than bytes, and that is the interesting part. A picture does not fit in a shared-memory reply — half a megabyte is the cap, and a screenful of PNG is past it — so the two processes use the filesystem they already share. It also makes the ordinary case free: the path goes straight back to registerImage, and the pixels never cross at all.

The file belongs to the caller from the moment it arrives. Nothing deletes it.

Sources/LavaUI/ScreenCapture.swift:26