Window

BuniumWindow is the main-process handle to one native window and one CEF view. Typed per the standing requirement — every option, getter, and event is exported.

import { BuniumWindow } from "bunium";

const win = new BuniumWindow({ url: "bunium://app/" });

Constructor options

BuniumWindowOptions (all optional except url):

Option	Type	Default	Notes
url	string	—	Initial URL.
width	number	800	Logical (CSS px) content width.
height	number	600	Logical content height.
title	string	bunium	Window title.
transparent	boolean	false	Clear background — the desktop shows through wherever the page paints transparent pixels.
frame	boolean	true	false hides native chrome (title bar / traffic-light buttons). Frameless windows need a CSS drag region to move — see below.
resizable	boolean	true	false disables user resize entirely.
minWidth/minHeight	number	unset	Minimum content size for user resize.
maxWidth/maxHeight	number	unset	Maximum content size for user resize.
titleBarStyle	"default" | "hidden" | "hiddenInset"	"default"	macOS only. "hidden" extends the page under the title bar while keeping the traffic-light buttons in place; "hiddenInset" also nudges them to a standard inset position. Ignored on Windows/Linux and on frame: false windows.
trafficLightPosition	{ x: number; y: number }	unset	macOS only. Explicit traffic-light position (logical px from the title bar's top-left corner). Only applies with titleBarStyle: "hidden"/"hiddenInset".

Methods

Method	Signature	Notes
loadURL(url)	(url: string) => void	Navigate the window's view to a new URL.
resize(width, height)	(w, h) => void	Programmatic resize (logical px).
captureScreenshot()	() => Screenshot	Raw BGRA pixels of the latest frame at physical size. No PNG encoder bundled — pick your own image lib.
onClose(listener)	(cb: () => void) => void	Fires on user close (red button) or .close().
on(name, listener)	renderer → main IPC	See Typed IPC.
emit(name, payload)	main → renderer IPC	See Typed IPC.
close()	() => void	Double-close is a safe no-op.

Getters

• frameCount — bigint, frames painted by the view.
• innerSize — logical (CSS px) size, what the page sees.
• renderedSize — physical pixel size of the paint buffer (innerSize * devicePixelRatio).
• devicePixelRatio — the window's backing scale factor (2.0 on Retina).
• resizable — whether the user can resize; sizeConstraints — current min/max content constraints.

Screenshot

export interface Size {
  width: number;
  height: number;
}

export interface Screenshot {
  width: number;
  height: number;
  data: Uint8Array; // raw BGRA, top-left origin, width * height * 4 bytes
}

Transparency

transparent: true enables CEF's windowless alpha painting (binary, not a translucency slider). Verified behavior: a page painting an opaque red square in one corner produces alpha=255 at the square and alpha=0 everywhere else, read back via captureScreenshot().

Frameless windows

frame: false removes the native title bar/border, including the OS's own edge-drag resizing — bunium reimplements 6px edge hit-testing for frame: false + resizable: true windows (titled and non-resizable windows are unaffected). To move a frameless window, mark page elements with CSS -webkit-app-region: drag — bunium scans automatically. Note: a drag region is fully non-interactive (no Electron-style no-drag override for buttons inside one yet).

Custom title bar (macOS)

const win = new BuniumWindow({
  url: "bunium://app/",
  titleBarStyle: "hiddenInset",
  trafficLightPosition: { x: 16, y: 16 },
});

Lets your page draw its own title bar while keeping the native traffic-light buttons (close/minimize/zoom) — the same look Electron's titleBarStyle + trafficLightPosition produce on macOS. There's no Windows/Linux equivalent (both platforms ignore these options); use frame: false plus a CSS drag region there instead, same as any other frameless window.

Shutdown

One app singleton per process. app.init() is called implicitly by the first BuniumWindow; call app.shutdown() to stop the pump loop and tear down CEF.

import { app } from "bunium";

app.setAppRoot("/abs/path/to/dist"); // once, before any bunium:// loadURL
app.shutdown();                      // clean exit; also before relaunch

(relaunchApp() calls app.shutdown() internally — see Auto-update.)