DebugOverflowIndicatorMixin mixin

An mixin indicator that is drawn when a RenderObject overflows its container.

This is used by some RenderObjects that are containers to show where, and by how much, their children overflow their containers. These indicators are typically only shown in a debug build (where the call to paintOverflowIndicator is surrounded by an assert).

This class will also print a debug message to the console when the container overflows. It will print on the first occurrence, and once after each time that reassemble is called.

class MyRenderObject extends RenderAligningShiftedBox with DebugOverflowIndicatorMixin {
  MyRenderObject({
    AlignmentGeometry alignment,
    TextDirection textDirection,
    RenderBox child,
  }) : super.mixin(alignment, textDirection, child);

  Rect _containerRect;
  Rect _childRect;

  @override
  void performLayout() {
    // ...
    final BoxParentData childParentData = child.parentData;
    _containerRect = Offset.zero & size;
    _childRect = childParentData.offset & child.size;
  }

  @override
  void paint(PaintingContext context, Offset offset) {
    // Do normal painting here...
    // ...

    assert(() {
      paintOverflowIndicator(context, offset, _containerRect, _childRect);
      return true;
    }());
  }
}

Constructors

DebugOverflowIndicatorMixin()

Properties

alwaysNeedsCompositing → bool: Whether this render object always needs compositing. [...]
@protected, read-only, inherited
attached → bool: Whether this node is in a tree whose root is attached to something. [...]
read-only, inherited
constraints → Constraints: The layout constraints most recently supplied by the parent.
@protected, read-only, inherited
debugCanParentUseSize → bool: Whether the parent render object is permitted to use this render object's size. [...]
read-only, inherited
debugCreator ↔ dynamic: The object responsible for creating this render object. [...]
read / write, inherited
debugDoingThisLayout → bool: Whether performLayout for this render object is currently running. [...]
read-only, inherited
debugDoingThisPaint → bool: Whether paint for this render object is currently running. [...]
read-only, inherited
debugDoingThisResize → bool: Whether performResize for this render object is currently running. [...]
read-only, inherited
debugLayer → OffsetLayer: In debug mode, the compositing layer that this render object uses to repaint. [...]
read-only, inherited
debugNeedsLayout → bool: Whether this render object's layout information is dirty. [...]
read-only, inherited
debugNeedsPaint → bool: Whether this render object's paint information is dirty. [...]
read-only, inherited
debugSemantics → SemanticsNode: The semantics of this render object. [...]
read-only, inherited
depth → int: The depth of this node in the tree. [...]
read-only, inherited
hashCode → int: The hash code for this object. [...]
read-only, inherited
isRepaintBoundary → bool: Whether this render object repaints separately from its parent. [...]
read-only, inherited
layer → OffsetLayer: The compositing layer that this render object uses to repaint. [...]
read-only, inherited
needsCompositing → bool: Whether we or one of our descendants has a compositing layer. [...]
read-only, inherited
owner → PipelineOwner: The owner for this node (null if unattached). [...]
read-only, inherited
paintBounds → Rect: An estimate of the bounds within which this render object will paint. Useful for debugging flags such as debugPaintLayerBordersEnabled. [...]
read-only, inherited
parent → AbstractNode: The parent of this node in the tree.
read-only, inherited
parentData ↔ ParentData: Data for use by the parent render object. [...]
read / write, inherited
runtimeType → Type: A representation of the runtime type of the object.
read-only, inherited
semanticBounds → Rect: The bounding box, in the local coordinate system, of this object, for accessibility purposes.
read-only, inherited
sizedByParent → bool: Whether the constraints are the only input to the sizing algorithm (in particular, child nodes have no impact). [...]
@protected, read-only, inherited

Methods

paintOverflowIndicator(PaintingContext context, Offset offset, Rect containerRect, Rect childRect, { String overflowHints }) → void: To be called when the overflow indicators should be painted. [...]
reassemble() → void: Cause the entire subtree rooted at the given RenderObject to be marked dirty for layout, paint, etc, so that the effects of a hot reload can be seen, or so that the effect of changing a global debug flag (such as debugPaintSizeEnabled) can be applied. [...]
override
adoptChild(covariant RenderObject child) → void: Called by subclasses when they decide a render object is a child. [...]
inherited
applyPaintTransform(covariant RenderObject child, Matrix4 transform) → void: Applies the transform that would be applied when painting the given child to the given matrix. [...]
inherited
assembleSemanticsNode(SemanticsNode node, SemanticsConfiguration config, Iterable<SemanticsNode> children) → void: Assemble the SemanticsNode for this RenderObject. [...]
inherited
attach(covariant PipelineOwner owner) → void: Mark this node as attached to the given owner. [...]
inherited
clearSemantics() → void: Removes all semantics from this render object and its descendants. [...]
@mustCallSuper, inherited
debugAssertDoesMeetConstraints() → void: Verify that the object's constraints are being met. Override this function in a subclass to verify that your state matches the constraints object. This function is only called in checked mode and only when needsLayout is false. If the constraints are not met, it should assert or throw an exception.
@protected, inherited
debugDescribeChildren() → List<DiagnosticsNode>: Returns a list of DiagnosticsNode objects describing this node's children. [...]
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node. [...]
@protected, inherited
debugPaint(PaintingContext context, Offset offset) → void: Override this method to paint debugging information.
inherited
debugRegisterRepaintBoundaryPaint({bool includedParent: true, bool includedChild: false }) → void: Called, in checked mode, if isRepaintBoundary is true, when either the this render object or its parent attempt to paint. [...]
inherited
debugResetSize() → void: If a subclass has a "size" (the state controlled by parentUsesSize, whatever it is in the subclass, e.g. the actual size property of RenderBox), and the subclass verifies that in checked mode this "size" property isn't used when debugCanParentUseSize isn't set, then that subclass should override debugResetSize to reapply the current values of debugCanParentUseSize to that state.
@protected, inherited
describeApproximatePaintClip(covariant RenderObject child) → Rect: Returns a rect in this object's coordinate system that describes the approximate bounding box of the clip rect that would be applied to the given child during the paint phase, if any. [...]
inherited
describeSemanticsClip(covariant RenderObject child) → Rect: Returns a rect in this object's coordinate system that describes which SemanticsNodes produced by the child should be included in the semantics tree. SemanticsNodes from the child that are positioned outside of this rect will be dropped. Child SemanticsNodes that are positioned inside this rect, but outside of describeApproximatePaintClip will be included in the tree marked as hidden. Child SemanticsNodes that are inside of both rect will be included in the tree as regular nodes. [...]
inherited
describeSemanticsConfiguration(SemanticsConfiguration config) → void: Report the semantics of this node, for example for accessibility purposes. [...]
@protected, inherited
detach() → void: Mark this node as detached. [...]
@mustCallSuper, inherited
dropChild(covariant RenderObject child) → void: Called by subclasses when they decide a render object is no longer a child. [...]
inherited
getTransformTo(RenderObject ancestor) → Matrix4: Applies the paint transform up the tree to ancestor. [...]
inherited
handleEvent(PointerEvent event, covariant HitTestEntry entry) → void: Override this method to handle pointer events that hit this render object.
inherited
invokeLayoutCallback<T extends Constraints>(LayoutCallback<T> callback) → void: Allows mutations to be made to this object's child list (and any descendants) as well as to any other dirty nodes in the render tree owned by the same PipelineOwner as this object. The callback argument is invoked synchronously, and the mutations are allowed only during that callback's execution. [...]
@protected, inherited
layout(Constraints constraints, { bool parentUsesSize: false }) → void: Compute the layout for this render object. [...]
inherited
markNeedsCompositingBitsUpdate() → void: Mark the compositing state for this render object as dirty. [...]
inherited
markNeedsLayout() → void: Mark this render object's layout information as dirty, and either register this object with its PipelineOwner, or defer to the parent, depending on whether this object is a relayout boundary or not respectively. [...]
inherited
markNeedsLayoutForSizedByParentChange() → void: Mark this render object's layout information as dirty (like markNeedsLayout), and additionally also handle any necessary work to handle the case where sizedByParent has changed value. [...]
inherited
markNeedsPaint() → void: Mark this render object as having changed its visual appearance. [...]
inherited
markNeedsSemanticsUpdate() → void: Mark this node as needing an update to its semantics description. [...]
inherited
markParentNeedsLayout() → void: Mark this render object's layout information as dirty, and then defer to the parent. [...]
@protected, inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a non-existent method or property is accessed. [...]
inherited
paint(PaintingContext context, Offset offset) → void: Paint this render object into the given context at the given offset. [...]
inherited
performLayout() → void: Do the work of computing the layout for this render object. [...]
@protected, inherited
performResize() → void: Updates the render objects size using only the constraints. [...]
@protected, inherited
redepthChild(AbstractNode child) → void: Adjust the depth of the given child to be greater than this node's own depth. [...]
@protected, inherited
redepthChildren() → void: Adjust the depth of this node's children, if any. [...]
inherited
replaceRootLayer(OffsetLayer rootLayer) → void: Replace the layer. This is only valid for the root of a render object subtree (whatever object scheduleInitialPaint was called on). [...]
inherited
rotate({int oldAngle, int newAngle, Duration time }) → void: Rotate this render object (not yet implemented).
inherited
scheduleInitialLayout() → void: Bootstrap the rendering pipeline by scheduling the very first layout. [...]
inherited
scheduleInitialPaint(ContainerLayer rootLayer) → void: Bootstrap the rendering pipeline by scheduling the very first paint. [...]
inherited
scheduleInitialSemantics() → void: Bootstrap the semantics reporting mechanism by marking this node as needing a semantics update. [...]
inherited
sendSemanticsEvent(SemanticsEvent semanticsEvent) → void: Sends a SemanticsEvent associated with this render object's SemanticsNode. [...]
inherited
setupParentData(covariant RenderObject child) → void: Override to setup parent data correctly for your children. [...]
inherited
showOnScreen({RenderObject descendant, Rect rect, Duration duration: Duration.zero, Curve curve: Curves.ease }) → void: Attempt to make (a portion of) this or a descendant RenderObject visible on screen. [...]
inherited
toDiagnosticsNode({String name, DiagnosticsTreeStyle style }) → DiagnosticsNode: Returns a debug representation of the object that is used by debugging tools and by toStringDeep. [...]
inherited
toString({DiagnosticLevel minLevel }) → String: Returns a string representation of this object.
inherited
toStringDeep({String prefixLineOne: '', String prefixOtherLines: '', DiagnosticLevel minLevel: DiagnosticLevel.debug }) → String: Returns a description of the tree rooted at this node. If the prefix argument is provided, then every line in the output will be prefixed by that string.
inherited
toStringShallow({String joiner: '; ', DiagnosticLevel minLevel: DiagnosticLevel.debug }) → String: Returns a one-line detailed description of the render object. This description is often somewhat long. [...]
inherited
toStringShort() → String: Returns a human understandable name.
inherited
visitChildren(RenderObjectVisitor visitor) → void: Calls visitor for each immediate child of this render object. [...]
inherited
visitChildrenForSemantics(RenderObjectVisitor visitor) → void: Called when collecting the semantics of this node. [...]
inherited

Operators

operator ==(dynamic other) → bool: The equality operator. [...]
inherited

rendering library

DebugOverflowIndicatorMixin mixin

Constructors

Properties

Methods

Operators