C

LabelStyleBase<TVisual>
abstract

Show Usages
An abstract base class that makes it possible to easily implement a custom ILabelStyle.
ImplementsInheritance Hierarchy

Remarks

Only createVisual and getPreferredSize need to be implemented by subclasses, however to improve rendering performance it is highly recommended to implement at least updateVisual, too.

Unlike a direct ILabelStyle implementation, LabelStyleBase<TVisual> does not expose a separate ILabelStyleRenderer. The base class uses a fixed renderer and simply forwards its calls back to the style instance.

Note that if your subclass has private fields (defined with JavaScript's # name syntax), the clone method needs to be overridden for the cloning to work properly.

Type Parameters

TVisual

The optional type of the created and updated by the and methods. This type argument can be omitted, but specifying a more concrete type helps conveniently implementing with TypeScript.

See Also

Developer's Guide

Demos

Shows how to create custom styles for nodes, edges, labels, ports, and edge arrows.
Visualize a label using a basic text element
Let the label style set the desired label size
Optimize the render performance of the label style

Members

Show:

Constructors

LabelStyleBase

()
protected
Initializes a new instance of the LabelStyleBase<TVisual> class.

Properties

renderer

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

Methods

clone

(): Object
Creates a new object that is a copy of the current instance.

Immutable subclasses should consider returning this for the best performance.

The base class implementation creates a simple shallow clone that copies all own properties to a new instance. This will not work for classes that use private fields or properties (defined with JavaScript's # name syntax) as no constructors will be run and implementations like this cannot be accessed from outside the classes that declare them.

Classes that use private members or require special initialization must override this method and manually create a new instance or call super.clone() and then explicitly copy the private fields and properties explicitly.

Return Value

Object
A new object that is a copy of this instance using a memberwise clone.

createVisual

(context: IRenderContext, label: ILabel): TVisual
protectedabstract
Creates the visual.
This method is called in response to a createVisual call to the instance that has been queried from the renderer.
protectedabstract

Parameters

context: IRenderContext
The render context.
label: ILabel
The label to which this style instance is assigned.

Return Value

TVisual
The visual as required by the createVisual interface.

See Also

API
updateVisual

getBounds

(context: ICanvasContext, label: ILabel): Rect
protected
Gets the bounds of the visual for the label in the given context.

This method is called in response to a getBounds call to the instance that has been queried from the renderer.

This implementation simply yields the bounds of the layout of the given label.

protected

Parameters

context: ICanvasContext
The canvas context.
label: ILabel
The label to which this style instance is assigned.

Return Value

Rect
The visual bounds of the visual representation.

getPreferredSize

(label: ILabel): Size
protectedabstract
Returns the preferred size of the label.
protectedabstract

Parameters

label: ILabel
The label to which this style instance is assigned.

Return Value

Size
The preferred size.

isHit

(
context: IInputModeContext
location: Point
label: ILabel
): boolean
protected
Determines whether the visual representation of the label has been hit at the given location.

This method is called in response to a isHit call to the instance that has been queried from the renderer.

This implementation returns the result of the contains method invoked for the layout of the label, the given point and the hitTestRadius of the ICanvasContext.

protected

Parameters

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

Return Value

boolean
true if the specified label representation is hit; false otherwise.

isInBox

(
context: IInputModeContext
rectangle: Rect
label: ILabel
): boolean
protected
Determines whether the visualization for the specified label is included in the marquee selection.

This method is called in response to a isInBox call to the instance that has been queried from the renderer.

This implementation returns the result of the intersects method invoked on rectangle for the layout of the label and the context.

protected

Parameters

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

Return Value

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

isInPath

(
context: IInputModeContext
path: GeneralPath
label: ILabel
): boolean
protected
Determines whether the visualization for the specified label is included in the lasso selection.
This method is called in response to a isInPath call to the instance that has been queried from the renderer.
protected

Parameters

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

Return Value

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

isVisible

(
context: ICanvasContext
rectangle: Rect
label: ILabel
): boolean
protected
Determines whether the visualization for the specified label is visible in the context.

This method is called in response to a isVisible call to the instance that has been queried from the renderer.

This implementation simply tests whether the bounds intersect the clip.

protected

Parameters

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

Return Value

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

lookup

(label: ILabel, type: Constructor): any
protected
Performs the lookup operation for the getContext that has been queried from the renderer.

This implementation yields null for everything but:

For these interfaces an implementation will be returned that delegates to the methods in this instance.

protected

Parameters

label: ILabel
The label 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: TVisual
label: ILabel
): TVisual
protected
Updates the visual previously created by createVisual.
This method is called in response to a updateVisual call to the instance that has been queried from the renderer. This implementation simply delegates to createVisual so subclasses should override to improve rendering performance.
protected

Parameters

context: IRenderContext
The render context.
oldVisual: TVisual
The visual that has been created in the call to createVisual.
label: ILabel
The label to which this style instance is assigned.

Return Value

TVisual
The visual as required by the createVisual interface.

See Also

API
createVisual

Static Methods

createLayoutTransform

(
context: IRenderContext
layout: IOrientedRectangle
autoFlip: boolean
): Matrix
static
Creates a transform matrix that can be applied to a Visual to arrange it according to the given layout and autoFlip rule.
static

Parameters

context: IRenderContext
The render context.
layout: IOrientedRectangle
The layout used to create the transform matrix.
autoFlip: boolean
Whether to automatically flip the matrix by 180 degrees, if the result would be pointing downwards.

Return Value

Matrix
The transform matrix.