Package limn.scene

@NullMarked package limn.scene

Widget tree, event dispatch (coalescing + bubbling), focus and the measure/layout pass.

Related Packages

Package	Description
limn.scene.event	The input events the scene dispatches: MouseEvent, KeyEvent, CharEvent for committed text and PreeditEvent for IME composition still in flight.
limn.scene.layout	Layout containers: Row and Column over the shared simplified flexbox Flex, with Expanded taking a weighted share of the leftover main-axis space; Wrap places children along a line and starts a new line below when the next one does not fit; Grid places them in a fixed number of columns, row by row, so that they line up on both axes; Stack overlays children, Padding wraps one child in edge insets, SizedBox fixes a dimension or spaces rigidly, Opacity draws one child as one picture at an opacity and fades it, and Transform draws one child moved, scaled or flipped without moving anything layout placed.

Class	Description
Change	What changed on a widget, and what moved it.
Change.Aspect	What about the widget changed.
Change.Origin	What moved the change, and the whole of this record's rule: The handler runs when, and only when, the user operated this widget.
Change.State	Every aspect but a text edit; Change.State.aspect() is never Change.Aspect.TEXT.
Change.TextEdit	A text edit: Change.TextEdit.aspect() is always Change.Aspect.TEXT, so aspect() == TEXT and instanceof Change.TextEdit are the same question in both directions.
ChangeObserver	A watcher: told about every change to a widget, whatever moved it.
Constraints	Layout constraints handed down the tree (Flutter/Compose style): a widget's measured size must fall inside [minWidth..maxWidth] x [minHeight..maxHeight].
ControlSize	The size step of a control: a deliberate, hand-tuned design axis, not a scale factor and not a DPI setting (that is Canvas.contentScale(), applied downstream in the backend; the two multiply, in that order, and must never be conflated).
EditCommand	One of the six commands of an Edit menu, done by whichever widget has the keyboard.
FloatConsumer	The float callback the JDK does not have, for the widgets whose value is a float.
FrameMetrics	Rolling per-frame performance samples the Scene collects each frame: frames-per-second, CPU frame time (tick + layout + paint, in ms), input-processing time (ms), and how much of the scene each frame actually repainted.
FrameMetrics.Metric	A fixed-capacity ring of recent samples (oldest evicted first) exposing the latest value, the windowed average/max, and a copy of the history for a sparkline.
Insets	Edge insets in logical points (padding/margins), by the reading direction: start is the side a line of text starts from and end the side it ends at, the left and the right in a layout that reads left to right and the right and the left in one that reads right to left.
LayoutDirection	The direction a subtree lays out in: an inherited design axis, not a transform and not a property of the locale.
Scene	Owns a widget tree bound to one window: queues native input (with coalescing), dispatches events with hit-testing and bubbling, tracks hover, click synthesis and keyboard focus (Tab traversal in layout order), ticks animations and runs the two-phase layout before painting.
Scene.Ticker	Animation hook, called once per frame while registered.
Scrollable	SPI for widgets that can scroll their content programmatically: scroll containers (ScrollView), virtualized lists (ListView), overflow strips, popup panels.
Size	A measured widget size in logical points.
SystemPreferences	Three preferences the user sets for every application on their desktop: a light or dark appearance, less motion, and more contrast.
SystemPreferences.ColorScheme	A light or dark appearance, or none chosen.
SystemPreferences.ContrastColors	The palette a user chose when the platform's request for more contrast is a palette of its own: a Windows contrast theme, whose eight system colours every native application draws with.
TooltipStyle	Appearance of the scene's hover tooltip panel.
Widget<W extends Widget<W>>	Base of the widget tree.