CompositeWidget¶

A widget that contains child widgets. Extends Widget with child grid storage, compositing, and resize propagation.

Uses dirty-flag coalescing: when a child grid arrives, the grid is stored and the widget marks itself dirty. A deferred self-message triggers the actual recompose. Multiple grids arriving in quick succession are batched into a single render pass.

The user implements state(). Override render_background() to draw custom content behind children (default is an empty grid). Override render() for custom child compositing (e.g. HBox/VBox).

trait tag CompositeWidget is
  Widget tag,
  WidgetParent tag

Implements¶

Widget tag
WidgetParent tag

Public Behaviours¶

receive_grid¶

[Source]

Receive a child's grid and store it. Only updates grids for children previously registered via register_child, pack_start/pack_end, or set_child. Unknown senders are ignored.

be receive_grid(
  widget: Any tag,
  grid: Grid val)

Parameters¶

widget: Any tag
grid: Grid val

resize¶

[Source]

Update size, propagate resize to all children, and re-render.

be resize(
  w: USize val,
  h: USize val)

Parameters¶

w: USize val
h: USize val

trigger_render¶

[Source]

be trigger_render()

receive_key¶

[Source]

be receive_key(
  key: KeyEvent val)

Parameters¶

key: KeyEvent val

receive_focus¶

[Source]

be receive_focus()

receive_blur¶

[Source]

be receive_blur()

set_debug_bg¶

[Source]

be set_debug_bg(
  color: (Default val | Black val | Red val | 
    Green val | Yellow val | Blue val | 
    Magenta val | Cyan val | White val | 
    BrightBlack val | BrightRed val | BrightGreen val | 
    BrightYellow val | BrightBlue val | BrightMagenta val | 
    BrightCyan val | BrightWhite val | Rainbow val))

Parameters¶

color: (Default val | Black val | Red val | Green val | Yellow val | Blue val | Magenta val | Cyan val | White val | BrightBlack val | BrightRed val | BrightGreen val | BrightYellow val | BrightBlue val | BrightMagenta val | BrightCyan val | BrightWhite val | Rainbow val)

Public Functions¶

render_background¶

[Source]

Produce the background grid before children are composited on top. Default: empty grid using the widget's debug_bg color.

fun ref render_background()
: Grid val

Returns¶

Grid val

register_child¶

[Source]

Register a child widget. Required before the child can send grids or receive resize propagation. Call from the constructor after creating child widgets.

fun ref register_child(
  widget: Widget tag)
: None val

Parameters¶

widget: Widget tag

Returns¶

None val

render¶

[Source]

Render background, then overlay all child grids on top. Non-empty cells from children overwrite the background.

fun ref render()
: Grid val

Returns¶

Grid val

state¶

[Source]

fun ref state()
: WidgetState ref

Returns¶

WidgetState ref

render_and_send¶

[Source]

fun ref render_and_send()
: None val

Returns¶

None val