WidgetDecoration class

Show widget as decoration on the chart

If using this as item that will show values make sure you apply margin from ChartState.defaultMargin this will make sure you are in chart area when you draw your decoration.

Example of drawing TargetLineDecoration with WidgetDecoration:

WidgetDecoration(
 builder: (context, chartState, itemWidth, verticalMultiplier) {
  return Container(

  // This will make sure that child is in chart area.
   margin: chartState.defaultMargin,
   child: Stack(
    children: [

     // This will show a target line that can also be shown by using [TargetLineDecoration]
     Positioned(
      left: 0,
      right: 0,

      // Show target line at item height of 4
      bottom: 4 * verticalMultiplier,
      height: 2,
      child: Container(color: Colors.red),
     ),
    ],
   ),
  );
 },
),

In case you just want to add image or something that is not relevant to current chart data you don't have to set any margins

Inheritance

Constructors

WidgetDecoration({required WidgetDecorationBuilder widgetDecorationBuilder, EdgeInsets margin = EdgeInsets.zero})
Constructor for selected item decoration

Properties

hashCode → int
The hash code for this object.
no setterinherited
margin → EdgeInsets
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
widgetDecorationBuilder → WidgetDecorationBuilder
Builder for widget decoration
final

Methods

animateTo(DecorationPainter endValue, double t) → DecorationPainter
Animate to next decoration state, each decoration should implement this. This is just regular lerp function, but instead of static function where you pass start and end state, here we start with current state and animate to endValue.
override
applyPaintTransform(ChartState state, Size size) → Offset
inherited
draw(Canvas canvas, Size size, ChartState state) → void
Draw decoration. Decoration can be foreground or background decoration that will be drawn on the chart decorations can ignore padding and can use whole available canvas to draw.
override
getRenderer(ChartState state) → Widget
override
initDecoration(ChartState state) → void
Init decoration is first thing called on decorations, it will pass current ChartState so decoration can easily calculate needed stuff for their layout.
inherited
isSameType(DecorationPainter other) → bool
Used for animating, we just need to find matching type, don't actually check for equality since we want to animate from one state to other. Some decorations may consider overriding this in case multiples are used
inherited
layoutSize(BoxConstraints constraints, ChartState state) → Size
inherited
marginNeeded() → EdgeInsets
Get extra margin (not definable by the user). This makes sure that any decoration that leaves original drawing window is not drawing outside of that window (This is not enforced right now but it's unwanted behaviour)
override
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
paddingNeeded() → EdgeInsets
Get extra padding (not definable by user, calculated by decoration if needed). This makes sure that decoration will fit with the chart in wanted area.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited