ArcConnector (Starlink-UK API)

java.lang.Object
- diva.canvas.AbstractFigure
- - diva.canvas.connector.AbstractConnector
  - - diva.canvas.connector.ArcConnector

All Implemented Interfaces:

CanvasComponent, Connector, Figure, VisibleComponent, UserObjectContainer
```
public class ArcConnector
extends AbstractConnector
```
A Connector that draws itself in an arc. The connector draws itself approximately through the center of the figures that own the sites to which it is connected. The curvature of the arc can be specified in one of two ways, depending on which variable of the arc's shape remain constant as the distance between the two figures at the ends of the arc is varied:
1. Constant incident angle: The angle at which the arc connects to the figure remains constant. This is the default behaviour, and the default angle is 45 degrees.
2. Constant displacement at the maximum arc point, from the straight line drawn between the two end points of the connector. The default displacement is 20 (not for any good reason, but is has to be something...).

Currently, only the first is supported.

The connector uses an instance of PaintedPath to draw itself, so see that class for a more detailed description of the paint- and stroke-related methods.

Version:: $Revision: 1.14 $
Author:: Edward Lee (eal@eecs.berkeley.edu), John Reekie (johnr@eecs.berkeley.edu)

Field Summary

Fields
Modifier and Type Field and Description

protected static double _CLOSE_THRESHOLD
The threshold for when a source and a destination of an arc are considered close to one another.

Fields
Modifier and Type	Field and Description
`protected static double`	`_CLOSE_THRESHOLD` The threshold for when a source and a destination of an arc are considered close to one another.

Constructor Summary

Constructors
Constructor and Description

ArcConnector(Site tail, Site head)
Create a new arc connector between the given sites.

Constructors
Constructor and Description
`ArcConnector(Site tail, Site head)` Create a new arc connector between the given sites.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`double`	`getAngle()` Get the angle at which the arc leaves the tail figure.
`Point2D`	`getArcMidpoint()` Return the midpoint of the arc.
`double`	`getGamma()` Get the angle that determines the orientation of a self-loop.
`Site`	`getMidpointSite()` Get the site that marks the midpoint of the connector.
`boolean`	`getSelfLoop()` Get the flag saying whether this arc is to be drawn as a self-loop
`void`	`repositionLabel()` Tell the connector to reposition its label if it has one.
`void`	`route()` Tell the connector to route itself between the current positions of the head and tail sites.
`void`	`setAngle(double angle)` Set the angle at which the arc leaves the tail figure, in radians.
`void`	`setGamma(double gamma)` Set the angle that determines the orientation of a self-loop.
`void`	`setSelfLoop(boolean selfloop)` Set the flag that says that this arc is drawn as a "self-loop." Apart from changing (slightly) the way the arc geometry is determined, this method resets some internal variables so that the arc doesn't get into a "funny state" when switching between self-loops and non-self-loops.
`void`	`translate(double x, double y)` Translate the connector.
`void`	`translateMidpoint(double dx, double dy)` Translate the midpoint of the arc.

Methods inherited from class diva.canvas.connector.AbstractConnector
getBounds, getDashArray, getHeadEnd, getHeadSite, getLabelFigure, getLineWidth, getShape, getStroke, getStrokePaint, getTailEnd, getTailSite, headMoved, hit, intersects, paint, reroute, setDashArray, setHeadEnd, setHeadSite, setLabelFigure, setLineWidth, setShape, setStroke, setStrokePaint, setTailEnd, setTailSite, tailMoved, transform

Methods inherited from class diva.canvas.AbstractFigure
contains, getInteractor, getLayer, getOrigin, getParent, getToolTipText, getTransformContext, getUserObject, isVisible, paint, repaint, repaint, setInteractor, setParent, setToolTipText, setUserObject, setVisible

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface diva.canvas.Figure
contains, getInteractor, getLayer, getOrigin, getParent, getToolTipText, setInteractor, setParent, setToolTipText

Methods inherited from interface diva.canvas.VisibleComponent
isVisible, paint, setVisible

Methods inherited from interface diva.canvas.CanvasComponent
getTransformContext, repaint, repaint

Methods inherited from interface diva.util.UserObjectContainer
getUserObject, setUserObject

- Field Detail
  - _CLOSE_THRESHOLD
```
protected static double _CLOSE_THRESHOLD
```
    The threshold for when a source and a destination of an arc are considered close to one another. This determines how self-loops get drawn.
- Constructor Detail
  - ArcConnector
```
public ArcConnector(Site tail,
                    Site head)
```
    Create a new arc connector between the given sites. The connector is drawn with a width of one and in black, and at the default incident angle of 45 degrees (PI/4 radians).
- Method Detail
  - getAngle
```
public double getAngle()
```
    Get the angle at which the arc leaves the tail figure.
  - getGamma
```
public double getGamma()
```
    Get the angle that determines the orientation of a self-loop. Thie method should be used when saving an arc to an external representation, if the arc is a self-loop.
  - getArcMidpoint
```
public Point2D getArcMidpoint()
```
    Return the midpoint of the arc.
    
    Returns:
    
    The midpoint of the arc.
  - getMidpointSite
```
public Site getMidpointSite()
```
    Get the site that marks the midpoint of the connector.
    
    Returns:
    
    A site representing the midpoint of the arc.
  - getSelfLoop
```
public boolean getSelfLoop()
```
    Get the flag saying whether this arc is to be drawn as a self-loop
  - repositionLabel
```
public void repositionLabel()
```
    Tell the connector to reposition its label if it has one. The label is currently only positioned at the center of the arc.
    
    Specified by:
    
    repositionLabel in class AbstractConnector
  - route
```
public void route()
```
    Tell the connector to route itself between the current positions of the head and tail sites.
    
    Specified by:
    
    route in interface Connector
    
    Specified by:
    
    route in class AbstractConnector
  - setAngle
```
public void setAngle(double angle)
```
    Set the angle at which the arc leaves the tail figure, in radians. Because of the sign of the geometry, an arc with positive angle and with an arrowhead on its head will appear to be drawn counter-clockwise, and an arc with a negative angle will appear to be drawn clockwise. As a general rule, angles should be somewhat less than PI/2, and PI/4 a good general maximum figure. If the angle is outside the range -PI to PI, then it is corrected to lie within that range.
  - setGamma
```
public void setGamma(double gamma)
```
    Set the angle that determines the orientation of a self-loop. This value is roughly equal to the angle of the tangent to the loop at it's mid-point. This method is only intended for use when creating self-loop arcs from a saved representation.
  - setSelfLoop
```
public void setSelfLoop(boolean selfloop)
```
    Set the flag that says that this arc is drawn as a "self-loop." Apart from changing (slightly) the way the arc geometry is determined, this method resets some internal variables so that the arc doesn't get into a "funny state" when switching between self-loops and non-self-loops. Not, however, that ths method should only be called when the arc changes, otherwise manipulation won't work properly. Use getSelfLoop() to test the current state of this flag.
  - translate
```
public void translate(double x,
                      double y)
```
    Translate the connector. This method is implemented, since controllers may wish to translate connectors when the sites at both ends are moved the same distance.
    
    Specified by:
    
    translate in interface Figure
    
    Specified by:
    
    translate in class AbstractConnector
  - translateMidpoint
```
public void translateMidpoint(double dx,
                              double dy)
```
    Translate the midpoint of the arc. This method is not exact, but attempts to alter the shape of the arc so that the midpoint moves by something close to the given amount.

Class ArcConnector

Field Summary

Constructor Summary

Method Summary

Methods inherited from class diva.canvas.connector.AbstractConnector

Methods inherited from class diva.canvas.AbstractFigure

Methods inherited from class java.lang.Object

Methods inherited from interface diva.canvas.Figure

Methods inherited from interface diva.canvas.VisibleComponent

Methods inherited from interface diva.canvas.CanvasComponent

Methods inherited from interface diva.util.UserObjectContainer

Field Detail

_CLOSE_THRESHOLD

Constructor Detail

ArcConnector

Method Detail

getAngle

getGamma

getArcMidpoint

getMidpointSite

getSelfLoop

repositionLabel

route

setAngle

setGamma

setSelfLoop

translate

translateMidpoint