CRT

Single-child container that wraps the UI in a Matrix-style power-on / power-off animation. During the boot animation a horizontal band of green character rain expands from the centre line until the full height is visible; during shutdown it contracts back. In between, CRT is an invisible pass-through wrapper.

Constructor: NewCRT(id, class string) *CRT

Methods

• Add(widget Widget) error — set the wrapped child (single-child container)
• Children() []Widget — returns the wrapped child
• Start(interval time.Duration) — begin the power-on animation
• PowerOff(interval time.Duration, onDone func()) — run the power-off animation, then invoke onDone (typically ui.Quit)
• Layout() error — positions child to fill the CRT bounds; records animation end position
• Render(r *Renderer) — clips the child to the current animation band and overlays the scanline / phosphor effect

Notes

Wrap the root container with CRT, then call Start after ui.Layout() has run so screen dimensions are known. The animation areas are filled with a Matrix-style green character rain that grows brighter toward the scan edge, flanked by a flashing phosphor scanline. Rows of the child content fade from green monochrome to true colour after they are revealed (power-on) or before they are swallowed (power-off).

crt := zw.NewCRT("crt", "")
crt.Add(myRootContainer)
ui := zw.NewUI(theme, crt)
crt.Start(30 * time.Millisecond)
// later, wired to a quit shortcut:
//   crt.PowerOff(30*time.Millisecond, ui.Quit)
ui.Run()