C

DelegatingNodeStyle
abstract

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A foundational abstract implementation of INodeStyle that delegates its behavior to pre-configured style instances.

Remarks

This class supports three primary use cases:

  • Wrapping another style with a customized API. This is ideal for providing a simpler or domain-specific API by mapping properties from a subclass to the corresponding values of the delegated style. Subclasses typically return the preconfigured instance from getStyle and modify it in the constructor or through custom property setters.
  • Dynamically reconfiguring a style based on the target node. In this scenario, the implementation keeps one or more style instances as fields and switches between them in getStyle, depending on attributes of the node, such as its tag property. This approach may also involve dynamically reconfiguring the style instance for specific node instances. When appropriate, implementations may override clone to simply return this.
  • Replacing one part of the implementation of another style. Instead of subclassing another style, the implementation delegates to all but a subset of the various aspects to an existing implementation and provides its own implementation, otherwise, via overriding specific methods of the base NodeStyleBase<TVisual> class.

Subclasses must implement getStyle and should ensure that it executes quickly and without allocations.

See Also

Developer's Guide

API

getStyle

Members

Show:

Constructors

DelegatingNodeStyle

()
protected
Creates a new instance of this style.

Properties

renderer

: INodeStyleRenderer
readonly
Gets the renderer implementation for this instance.
The private implementation will delegate all API calls back to this instance.
readonlyfinal

Methods

clone

(): Object
Returns a memberwise clone.
Note that stateless subclasses that implement the flyweight pattern and do not carry any state can override this method and return this, instead, as the base implementation is completely stateless.

Return Value

Object
A clone of this instance.

createVisual

(context: IRenderContext, node: INode): Visual
protected
Creates the visual with the style from getStyle and the node from getNode.
protected

Parameters

context: IRenderContext
The render context.
node: INode
The node to which this style instance is assigned.

Return Value

Visual
The visual as required by the createVisual interface.

See Also

API
updateVisual

getBounds

(context: ICanvasContext, node: INode): Rect
protected
Gets the bounds with the style from getStyle and the node from getNode.
protected

Parameters

context: ICanvasContext
The canvas context.
node: INode
The node to which this style instance is assigned.

Return Value

Rect
The visual bounds of the visual representation.

getIntersection

(
node: INode
inner: Point
outer: Point
): Point
protected
Gets the intersection of a line with the visual representation of the node from getNode by using the style from getStyle.
protected

Parameters

node: INode
The node to which this style instance is assigned.
inner: Point
The coordinates of a point lying inside the shape.
outer: Point
The coordinates of a point lying outside the shape.

Return Value

Point
The intersection point if one has been found or null, otherwise.

getNode

(node: INode): INode
protected
Returns the node used for rendering.
Overriding this method allows for advanced customizations such as using a SimpleNode with modified layout and use it for rendering while preserving the original node's structure.
protected

Parameters

node: INode
The original node to be rendered.

Return Value

INode
The node used for rendering. By default, this method returns the provided node. Subclasses can override this method to return a different node, such as a SimpleNode, to customize rendering behavior.

getOutline

(node: INode): GeneralPath
protected
Gets the outline of the visual representation of the node from getNode by using the style from getStyle.
protected

Parameters

node: INode
The node to get the outline for.

Return Value

GeneralPath
The outline of the visual representation or null.

getStyle

(node: INode): INodeStyle
protectedabstract
Provides the core implementation of this style, returning the instance to delegate rendering logic.
This method should ideally return the same instance for identical items to ensure optimal performance. It should avoid performing expensive operations as it will be invoked frequently during rendering and other operations like hit-testing. Ideally, it should be implemented allocation-free.
protectedabstract

Parameters

node: INode
The node for which the style instance should be returned and applied.

Return Value

INodeStyle
The INodeStyle instance responsible for handling all related requests.

See Also

Developer's Guide

isHit

(
context: IInputModeContext
location: Point
node: INode
): boolean
protected
Determines with the style from getStyle whether the visualization of the node from getNode is hit at the given location.
protected

Parameters

context: IInputModeContext
The input mode context.
location: Point
The point to test.
node: INode
The node to which this style instance is assigned.

Return Value

boolean
true if the specified node is hit; false otherwise.

isInBox

(
context: IInputModeContext
rectangle: Rect
node: INode
): boolean
protected
Determines with the style from getStyle whether the visualization of the node from getNode is included in the marquee selection.
protected

Parameters

context: IInputModeContext
The input mode context.
rectangle: Rect
The marquee selection box.
node: INode
The node to which this style instance is assigned.

Return Value

boolean
true if the specified node is visible and selected by the marquee rectangle; false otherwise.

isInPath

(
context: IInputModeContext
path: GeneralPath
node: INode
): boolean
protected
Determines with the style from getStyle whether the visualization of the node from getNode is included in the lasso selection.
protected

Parameters

context: IInputModeContext
The input mode context.
path: GeneralPath
The lasso selection path.
node: INode
The node to which this style instance is assigned.

Return Value

boolean
true if the specified node is visible and selected by the lasso path; false otherwise.

isInside

(node: INode, location: Point): boolean
protected
Determines whether the provided point is inside the visual bounds of the node from getNode by using the style from getStyle.
protected

Parameters

node: INode
The node to which this style instance is assigned.
location: Point
The point to test.

Return Value

boolean
Whether the point is considered to lie inside the shape.

isVisible

(
context: ICanvasContext
rectangle: Rect
node: INode
): boolean
protected
Determines with the style from getStyle whether the visualization of the node from getNode is visible.
protected

Parameters

context: ICanvasContext
The canvas context.
rectangle: Rect
The clipping rectangle.
node: INode
The node to which this style instance is assigned.

Return Value

boolean
true if the specified node is visible in the clipping rectangle; false otherwise.

lookup

(node: INode, type: Constructor): any
protected
Performs the lookup operation with the style from getStyle and the node from getNode.
protected

Parameters

node: INode
The node to use for the context lookup.
type: Constructor
The type to query.

Return Value

any
An implementation of the type or null.

updateVisual

(
context: IRenderContext
oldVisual: Visual
node: INode
): Visual
protected
Updates the visual with the style from getStyle and the node from getNode.
protected

Parameters

context: IRenderContext
The render context.
oldVisual: Visual
The visual that has been created in the call to createVisual.
node: INode
The node to which this style instance is assigned.

Return Value

Visual
The visual as required by the createVisual interface.

See Also

API
createVisual