com.nwoods.jgo
Class JGoEllipse

java.lang.Object
  extended bycom.nwoods.jgo.JGoObject
      extended bycom.nwoods.jgo.JGoDrawable
          extended bycom.nwoods.jgo.JGoEllipse
All Implemented Interfaces:
JGoXMLSaveRestore, java.io.Serializable

public class JGoEllipse
extends JGoDrawable

Represents an ellipse object in a JGoView. The ellipse is defined by the rectangle which encloses it. An ellipse can be a circle if the rectangle is a square.

See Also:
Serialized Form

Field Summary
 
Fields inherited from class com.nwoods.jgo.JGoObject
Bottom, BottomCenter, BottomLeft, BottomMiddle, BottomRight, Center, CenterLeft, CenterRight, Changed4ResizeHandles, ChangedAutoRescale, ChangedBrush, ChangedDraggable, ChangedDragsNode, ChangedGeometry, ChangedGrabChildSelection, ChangedInitializing, ChangedPen, ChangedResizable, ChangedSelectable, ChangedUpdatePartner, ChangedVisible, ChangedZOrder, LastChangedHint, Left, LeftCenter, NoHandle, NoSpot, NumReservedHandles, RepaintAll, Right, RightCenter, SideLeft, SideRight, Top, TopCenter, TopLeft, TopMiddle, TopRight
 
Constructor Summary
JGoEllipse()
          Create an ellipse with no dimensions.
JGoEllipse(org.eclipse.swt.graphics.Point location, Dimension size)
          Create an ellipse with the given location and size.
JGoEllipse(org.eclipse.swt.graphics.Rectangle rect)
          Create an ellipse with the given bounding rectangle
 
Method Summary
 JGoObject copyObject(JGoCopyEnvironment env)
          Create a new instance of this object with the same field values.
static boolean getNearestIntersectionPoint(int left, int top, int width, int height, int px, int py, int cx, int cy, org.eclipse.swt.graphics.Point result)
          Compute the point along the edge of an ellipse that is closest to a given point on a straight line from that point to another given point.
static boolean getNearestIntersectionPoint(int left, int top, int width, int height, int px, int py, org.eclipse.swt.graphics.Point R)
          Compute the point along the edge of an ellipse that is closest to a given point on a straight line from that point to the center of that ellipse specified by the given bounds.
 boolean getNearestIntersectionPoint(int px, int py, int cx, int cy, org.eclipse.swt.graphics.Point result)
          Consider the pen width in determining the nearest intersection point.
 boolean isPointInObj(org.eclipse.swt.graphics.Point pnt)
          Instead of just checking the bounding rectangle, this sees if the given point is actually in the ellipse.
 void paint(Graphics2D g, JGoView view)
          Draw the ellipse on the screen.
 void SVGReadAttributes(DomElement svgElement)
          This method will read attributes from standard SVG elements.
 DomNode SVGReadObject(DomDoc svgDoc, JGoDocument jGoDoc, DomElement svgElement, DomElement jGoChildElement)
          Read this object in from a DomDoc representing a Scalable Vector Graphics (SVG) XML document.
 void SVGWriteAttributes(DomElement svgElement)
          This method will add attributes to standard SVG elements.
 void SVGWriteObject(DomDoc svgDoc, DomElement jGoElementGroup)
          Write this object out to a DomDoc representing a Scalable Vector Graphics (SVG) XML document.
 
Methods inherited from class com.nwoods.jgo.JGoDrawable
changeValue, copyNewValueForRedo, draw3DRect, draw3DRect, drawEllipse, drawEllipse, drawEllipse, drawLine, drawLine, drawPath, drawPolygon, drawPolygon, drawRect, drawRect, drawRect, drawRoundRect, drawRoundRect, expandRectByPenWidth, getBrush, getPen, setBrush, setPen, SVGAddPathArgs, SVGUpdateReference
 
Methods inherited from class com.nwoods.jgo.JGoObject
canView, computeBoundingRect, computeMove, computeResize, copy, copyObjectDelayed, copyOldValueForUndo, copyRect, doMouseClick, doMouseDblClick, doUncapturedMouseMove, findCommonParent, foredate, gainedSelection, geometryChange, geometryChangeChild, getBoundingRect, getDocument, getDraggingObject, getFlags, getHeight, getLayer, getLeft, getLocation, getLocation, getParent, getParentJGoNode, getParentNode, getPartner, getRectangleSpotLocation, getSize, getSize, getSpotLocation, getSpotLocation, getToolTipText, getTop, getTopLeft, getTopLeft, getTopLevelObject, getView, getWidth, growRect, handleMove, handleResize, hideSelectionHandles, is4ResizeHandles, isAutoRescale, isBoundingRectInvalid, isChildOf, isDraggable, isDragsNode, isInitializing, isResizable, isSelectable, isSkipsUndoManager, isSuspendUpdates, isTopLevel, isUpdatePartner, isVisible, lostSelection, ownerChange, partnerUpdate, pick, redirectSelection, remove, set4ResizeHandles, setAutoRescale, setBoundingRect, setBoundingRect, setBoundingRect, setBoundingRectInvalid, setBoundsRect, setDraggable, setDragsNode, setFlags, setHeight, setInitializing, setLeft, setLocation, setLocation, setLocationOffset, setLocationOffset, setParent, setPartner, setRectangleSpotLocation, setResizable, setSelectable, setSize, setSize, setSizeKeepingLocation, setSkipsUndoManager, setSpotLocation, setSpotLocation, setSpotLocation, setSpotLocationOffset, setSuspendUpdates, setTop, setTopLeft, setTopLeft, setUpdatePartner, setVisible, setWidth, showSelectionHandles, spotOpposite, update, update
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

JGoEllipse

public JGoEllipse()
Create an ellipse with no dimensions.


JGoEllipse

public JGoEllipse(org.eclipse.swt.graphics.Rectangle rect)
Create an ellipse with the given bounding rectangle

Parameters:
rect - the bounding rectangle.

JGoEllipse

public JGoEllipse(org.eclipse.swt.graphics.Point location,
                  Dimension size)
Create an ellipse with the given location and size.

Parameters:
location - the location of the ellipse.
size - the size of the ellipse.
Method Detail

copyObject

public JGoObject copyObject(JGoCopyEnvironment env)
Create a new instance of this object with the same field values.

Overrides:
copyObject in class JGoDrawable
Parameters:
env - the environment for the copy operation - keeps track of copied objects.

SVGWriteObject

public void SVGWriteObject(DomDoc svgDoc,
                           DomElement jGoElementGroup)
Description copied from interface: JGoXMLSaveRestore
Write this object out to a DomDoc representing a Scalable Vector Graphics (SVG) XML document.

This method will be called by com.nwoods.jgo.svg.DefaultDocument.SVGWriteDoc() for every JGoObject contained within a JGoDocument. The following example uses a JGoRectangle to illustrate the format of a generated SVG JGoObject:

<g>
<JGoClass class="com.nwoods.jgo.JGoRectangle"\>
<rect height="75" style="stroke:black;stroke-width:1;fill:rgb(255,0,0);" width="75" x="65" y="71"/>
<JGoClass class="com.nwoods.jgo.JGoDrawable" drawablebrush="jgoid1" drawablepen="jgoid2" embeddedpenbrush="false"/>
<JGoClass class="com.nwoods.jgo.JGoObject" obj_flags="1054"/>
</g>

Note that the entire JGoObject is enclosed in a group (<g>). Each subclass of the JGoObject is described by a <JGoClass> element, starting with the most specific class and moving to the more general. Each <JGoClass> element has a "class" attribute which defines the class name. Each <JGoClass> element may also have several other attributes which uniquely describe that state of that class. Following the <JGoClass> element, each class may also genereate any other elements that are required, including representations of contained objects and standard SVG elements such as the <rect> element shown in the above example. The generation of SVG elements in the output makes it possible for the output to be read by SVG viewers and other SVG aware applications. The information contained in the <JGoClass> elements allows us to accurately save and restore all the information in a particular JGoObject subclass.

If this class contains a reference to another object, call DomDoc.registerReferencingNode() to register that reference. This will cause the element representing the referenced object to be identified with a unique id attribute, and cause the element representing the referring object to have a user defined attribute containing a reference to that id. See DomDoc.registerReferencingNode() for more information.

Typically, an implementation of this method will generate a <JGoClass> element using the DomDoc.createJGoClassElement() method, adding whatever attributes are necessary to describe the class. It will then call its superclass so that the superclass can add its own <JGoClass> element and other information to jGoElementGroup within the DomDoc.

Refer to com.nwoods.jgo.examples.flower.ActivityNode.SVGWriteObject() and com.nwoods.jgo.examples.SimpleNode.SVGWriteObject() for examples using this method.

Refer to the file com.nwoods.jgo.svg\xsvg.dtd for a formal description of JGo extensions to the SVG document type.

Specified by:
SVGWriteObject in interface JGoXMLSaveRestore
Overrides:
SVGWriteObject in class JGoDrawable

SVGReadObject

public DomNode SVGReadObject(DomDoc svgDoc,
                             JGoDocument jGoDoc,
                             DomElement svgElement,
                             DomElement jGoChildElement)
Description copied from interface: JGoXMLSaveRestore
Read this object in from a DomDoc representing a Scalable Vector Graphics (SVG) XML document.

This method will be called by com.nwoods.jgo.svg.DefaultDocument.SVGReadDoc() for every <JGoClass> element encountered in a DomDoc. First, an object of the type specified by the class attribute will be created and then the SVGReadObject() method will be called on that newly created object. Refer to SVGWriteObject() for a description of the expected format of the SVG document.

This method may also be called by com.nwoods.jgo.svg.DefaultDocument.SVGReadDoc() when reading any SVG document, including those not generated by JGo and therefore not containing any <JGoClass> elements. In such cases, the DefaultDocument.SVGReadElement() method may be subclassed to examine the SVG element and cause the appropriate JGoObject to be created to represent that element and call SVGReadObject() on that newly created object. By default, standard JGoObjects such as JGoRectangles, JGoStrokes, etc will be created to represent these objects.

If this class contains a reference to another object, call DomDoc.registerReferencingObject() to register that reference. This will cause the JGoObject.SVGUpdateReference() to be called on the referencing object after all the objects have been created, passing in the object befing referenced. See DomDoc.registerReferencingObject() for more information.

Typically, an implementation of this method starts by verifying that the element being read is a <JGoClass> element (which will be true if jGoChildElement is not null). This will always be true unless you have subclassed the DefaultDocument.SVGReadElement() method as described above. It will then read the expected attributes of the <JGoClass> element (as written by SVGReadObject()), call SVGReadObject() on its superclass, and finally return the next element by calling svgElement.getNextSibling().

Refer to com.nwoods.jgo.examples.flower.ActivityNode.SVGReadObject() and com.nwoods.jgo.examples.SimpleNode.SVGReadObject() for examples using this method.

Specified by:
SVGReadObject in interface JGoXMLSaveRestore
Overrides:
SVGReadObject in class JGoDrawable

SVGWriteAttributes

public void SVGWriteAttributes(DomElement svgElement)
Description copied from class: JGoObject
This method will add attributes to standard SVG elements.

Call this method from SVGWriteObject() if standard SVG elements are generated by this class or if this class may be subclassed and it should contribute arguments to SVG elements. For example, the JGoDrawable class implements this method to add standard SVG attributes for stroke, fill, and width. The JGoRectangle class calls this method to add all appropriate attributes to the <rect> element it generates. It is not necessary to implement this method if this class does not contribute any attributes to standard SVG elements. It is not necessary to call this method from SVGWriteObject() if this class does not generate any standard SVG elements.

Typically, an implementation of this method will first call the superclass and then call DomElement.setAttribute() to add attributes for this class.

Overrides:
SVGWriteAttributes in class JGoDrawable

SVGReadAttributes

public void SVGReadAttributes(DomElement svgElement)
Description copied from class: JGoObject
This method will read attributes from standard SVG elements.

Call this method from SVGReadObject() if standard SVG elements are being read by this class or if this class may be subclassed and it should read arguments from SVG elements. For example, the JGoDrawable class implements this method to read standard SVG attributes for stroke, fill, and width. The JGoRectangle class calls this method to read all appropriate attributes from the <rect> element it is reading. It is not necessary to implement this method if this class does not read any attributes from standard SVG elements. It is not necessary to call this method from SVGReadObject() if this class does not read any standard SVG elements.

Typically, an implementation of this method will first call the superclass and then call DomElement.getAttribute() to read the attributes for this class.

Overrides:
SVGReadAttributes in class JGoDrawable

paint

public void paint(Graphics2D g,
                  JGoView view)
Draw the ellipse on the screen.

Overrides:
paint in class JGoObject
Parameters:
g - the graphics context on which to draw.
view - the view we're drawing in

isPointInObj

public boolean isPointInObj(org.eclipse.swt.graphics.Point pnt)
Instead of just checking the bounding rectangle, this sees if the given point is actually in the ellipse. Any pen width is ignored.

Overrides:
isPointInObj in class JGoObject
Parameters:
pnt - the point to check
Returns:
true if pnt is in this object

getNearestIntersectionPoint

public static boolean getNearestIntersectionPoint(int left,
                                                  int top,
                                                  int width,
                                                  int height,
                                                  int px,
                                                  int py,
                                                  org.eclipse.swt.graphics.Point R)
Compute the point along the edge of an ellipse that is closest to a given point on a straight line from that point to the center of that ellipse specified by the given bounds.

Parameters:
left - the left bounds of an ellipse
top - the top bounds of an ellipse
width - the width of an ellipse
height - the height of an ellipse
px - the X coordinate of a point that specifies a line to the center
py - the Y coordinate of a point that specifies a line to the center
R - a Point that is modified (must not be null)
Returns:
true

getNearestIntersectionPoint

public static boolean getNearestIntersectionPoint(int left,
                                                  int top,
                                                  int width,
                                                  int height,
                                                  int px,
                                                  int py,
                                                  int cx,
                                                  int cy,
                                                  org.eclipse.swt.graphics.Point result)
Compute the point along the edge of an ellipse that is closest to a given point on a straight line from that point to another given point.

We modify the given result Point to hold the point that is closest to (px,py). (cx,cy) is typically the center of the ellipse.

Parameters:
left - the left bounds of a rectangle
top - the top bounds of a rectangle
width - the width of a rectangle
height - the height of a rectangle
px - the X coordinate of a point that starts a line
py - the Y coordinate of a point that starts a line
cx - the X coordinate of a point that specifies the other end of the line
cy - the Y coordinate of a point that specifies the other end of the line
result - a Point that is modified (must not be null)
Returns:
whether the line from (px,py) to (cx,cy) intersects the rectangle

getNearestIntersectionPoint

public boolean getNearestIntersectionPoint(int px,
                                           int py,
                                           int cx,
                                           int cy,
                                           org.eclipse.swt.graphics.Point result)
Description copied from class: JGoDrawable
Consider the pen width in determining the nearest intersection point.

Overrides:
getNearestIntersectionPoint in class JGoDrawable