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Difference between revisions of "GEF/GEF4/FX"

< GEF‎ | GEF4
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The [[#Canvas|Canvas]] package provides a replacement for the [ javafx.embed.swt.FXCanvas], adding support for various JavaFX/SWT integration functionality.
==== FXCanvasEx ====
==== FXCanvasEx ====

Revision as of 07:48, 25 September 2015



The GEF4 FX component provides useful additions around JavaFX as well as for integrating JavaFX with SWT. It is internally composed out of four modules, namely FX, FX.SWT, and FX.JFace. There are also a couple of undeployed FX Examples and FX SWT Examples.





The {Root} package provides only provides the bundle activator, FxBundle.



The FxBundle is the bundle activator.


  • package: org.eclipse.gef4.fx.anchors

The Anchors package provides a visual anchor abstraction (IFXAnchor), a related abstract base implementation (AbstractFXAnchor), as well as concrete anchor implementations (FXStaticAnchor, FXChopBoxAnchor) to manage dynamic positioning of visuals in dependence of others.


IFXAnchor, AbstractFXAnchor, AnchorKey


When attaching an AnchorKey to an IFXAnchor, you can pass-in an arbitrary info object. This object can be evaluated by anchor implementations, therefore, it is used to provide additional information about the anchored, where necessary (see FXChopboxAnchor for an example).

The abstract base implementation AbstractFXAnchor triggers a re-computation for an attached AnchorKey when the anchorage visual changes relative to the anchored visual or vice versa. This is realized using a VisualChangeListener. When an AnchorKey is detached from an IFXAnchor, no further computations will be performed for that AnchorKey.

The anchorage visual and the positions for the anchoreds are managed using JavaFX Properties (JavaFX Properties and Binding), i.e. you can register change listeners and realize bindings based on those properties.




The FXChopBoxAnchor uses reference points to compute the anchor position for the anchored visuals. One reference point is referred to as the anchorage reference point. This point is the same for every anchored. It is computed based on the geometry of the anchorage. In addition, every anchored specifies one reference point. One anchor position is computed for each pair of (anchorage-reference-point, anchored-reference-point).


The following paragraphs describe the anchor computation in detail.


Here you can see how a connection is rendered with the FXChopBoxAnchor. The E letter shape is the anchorage visual. The blue point is the anchored visual. The green line is the connection from the anchored to the anchorage. Note that the connection is not drawn inside of the anchorage, but ends on its outline. We will see how this is implemented.


In addition to the previous screenshot, you can see the center point of the anchorage bounds here. When this point is inside of the anchorage, it is used as the anchorage reference point. If it would be used as the anchorage reference point in this case, then the connection would end at that point, i.e. in the middle of nowhere. That's why a better anchorage reference point has to be computed.


In order to find an anchorage reference point that actually is inside of the anchorage, the shape vertices of the anchorage are taken into consideration. You can see that the connection ends at one of those vertices. You may wonder how the vertex to use as the anchorage reference point is determined.


In addition to the vertices, you can see lines connecting the center of the bounds with each vertex. The lines indicate the distance of each vertex to the center. The vertex that is closest to the center is used as the anchorage reference point.


Two of the lines are highlighted and their distance is shown. The anchorage reference point is now determined (orange).


A second anchored reference point is added to demonstrate how the actual anchor position is determined. A line from each anchored reference point to the anchorage reference point is constructed and intersected with the anchorage's outline. The intersection point that is closest to the anchored reference point is used as the anchor position.


  • package: org.eclipse.gef4.fx.gestures

The Gestures package provides abstractions to compose related atomic JavaFX events into gestures, i.e. FXMouseDragGesture, FXPinchSpreadGesture, and FXRotateGesture. A gesture is implemented as an abstract class, with different abstract methods for the various parts of the gesture, i.e. press(), drag(), and release() in the case of an FXMouseDragGesture. Besides, every gesture provides a setScene() method to register/unregister JavaFX event listeners.



This FXMouseDragGesture reports mouse press, drag, and release events.




This FXRotateGesture reports touch rotate events, i.e. dragging two fingers around each other.


  • package: org.eclipse.gef4.fx.listeners







  • package: org.eclipse.gef4.fx.nodes

The Nodes package provides




The FXGeometryNode is a specific javafx.scene.shape.Path that is capable of displaying an org.eclipse.gef4.geometry.planar.IGeometry.


The FXGridLayer is a specific javafx.scene.layout.Pane, which displays a grid with constant spacing that can be used as a background grid.


The ScrollPaneEx is an alternative to the javafx.scene.control.ScrollPane. It consists of two layers: 1) a scrolled pane, and 2) a scrollbars group. The scrollbars group contains the horizontal and vertical scrollbars. It is rendered above the scrolled pane. A content group is wrapped inside the scrolled pane and contains all content. A viewport transformation is applied to this content group, i.e. scrolling is separated from the viewport transformation.

The ScrollPaneEx determines the scrollable bounds based on the content bounds and the viewport bounds (its size) and provides access to these bounds. It does also provide methods to compute a translation from a scrollbar ratio and vice versa.



Base image (grey X)

Overlayed image (red X)

FXConnection, IFXDecoration, IFXConnectionRouter, FXPolyBezierConnectionRouter, FXPolylineConnectionRouter

The FXConnection is an implementation of a connection with two endpoints and an arbitrary number of waypoints. One of the endpoints is referred to as the start point, the other one is referred to as the end point. The positions for endpoints and waypoints are computed using anchors, i.e. an FXConnection provides one AnchorKey per point and manages one IFXAnchor per point. However, the API also allows directly specifying coordinates for each point, in which case an FXStaticAnchor is created internally. An FXConnection works out-of-the-box in combination with FXChopBoxAnchor, i.e. it provides a special ReferencePointProvider implementation.

An FXConnection can have a start decoration and an end decoration which are displayed at the start point, or end point, respectively. A decoration implements the IFXDecoration interface. Decorations can be used to display an arrow at one end of a connection, for example.

An FXConnection manages an FXGeometryNode, which is referred to as the curve node. The ICurve which is displayed by the curve node is computed by an IFXConnectionRouter. The router receives the coordinates of all points of the connection (start point, way points, end point). Currently, two connection routers are provided: 1) the FXPolylineConnectionRouter (default), and 2) the FXPolyBezierConnectionRouter. The first one computes a org.eclipse.gef4.geometry.planar.Polyline (only straight line segments) from the given points while the second one computes a org.eclipse.gef4.geometry.planar.PolyBezier (consecutive Bezier curves with smooth continuity) from the given points.


The FXUtils class contains utility functionality, such as querying the current mouse pointer location, picking nodes at a current position on the scene graph, and performing local-to-parent, local-to-scene, parent-to-local, and scene-to-local transformations of geometries (GEF4 IGeometry).




  • package: org.eclipse.gef4.fx.swt.canvas








  • package: org.eclipse.gef4.fx.swt.controls







FXColorPicker, FXSimpleLinearGradientPicker, FXAdvancedLinearGradientPicker








  • package: org.eclipse.gef4.fx.ui.gestures
















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