Package edu.cnu.mdi.item

Class EllipseItem

java.lang.Object

edu.cnu.mdi.item.AItem

edu.cnu.mdi.item.PathBasedItem

edu.cnu.mdi.item.PolygonItem

edu.cnu.mdi.item.EllipseItem

All Implemented Interfaces:

IFeedbackProvider, IDrawable, EventListener

public class EllipseItem
extends PolygonItem

An ellipse item represented internally as a Path2D polygonal approximation.

Key invariants:

• The ellipse center is the item's focus (world coordinates).
• Width/height are stored as full extents in world units.
• Selection handles are the four cardinal points of the ellipse in its rotated frame (top/right/bottom/left).

Resize correctness after rotation depends on using the same azimuth convention everywhere. In this codebase, azimuth behaves like a compass bearing: 0° = north (+y), 90° = east (+x), increasing clockwise. That convention is used by WorldGraphicsUtils.project(Point2D.Double, double, double, Point2D.Double).

Field Summary

Fields inherited from class edu.cnu.mdi.item.AItem

_connectable, _deletable, _dirty, _displayName, _doubleClickable, _draggable, _enabled, _focus, _FOCUSFILL, _lastDrawnPolygon, _layer, _line, _locked, _modification, _path, _popupMenu, _resizable, _resizePolicy, _rightClickable, _rotatable, _selectable, _selected, _style, _styleEditable, _visible, rotateIcon, RPSIZE, RPSIZE2, SPSIZE, SPSIZE2

Constructor Summary

Constructors

Constructor	Description
EllipseItem(Layer layer, double w, double h, double azimuth, Point2D.Double center)	Create an ellipse.

Method Summary

Modifier and Type	Method	Description
double	getHeightWorld()
Point[]	getSelectionPoints(IContainer container)	Return the four selection handles in local (screen) coordinates.
double	getWidthWorld()
protected void	reshape()	Ellipse-specific reshape: update width/height based on which selection handle is dragged.
void	setSize(double w, double h)	Programmatically set ellipse size (full extents), clamped to MIN_SIZE.

Methods inherited from class edu.cnu.mdi.item.PolygonItem

setPath

Methods inherited from class edu.cnu.mdi.item.PathBasedItem

contains, drawItem, getBounds, getRotatePoint, getWorldBounds, modify, rotate, scale, shouldDraw, singlePointBounds, threePointAngle, translateWorld, updateFocus

Methods inherited from class edu.cnu.mdi.item.AItem

acceptModification, applyGeometryProperties, applyProperties, applyStyleProperties, createPopupMenu, doubleClicked, draw, drawSelections, enclosed, equals, focusFill, geometryChanged, getAzimuth, getContainer, getDisplayName, getFeedbackStrings, getFocus, getFocusPoint, getItemModification, getLastDrawnPolygon, getLayer, getLine, getPath, getPopupMenu, getResizePolicy, getStyle, getStyleSafe, getView, hashCode, inASelectRect, inRotatePoint, inSelectPoint, isConnectable, isDeletable, isDirty, isDoubleClickable, isDraggable, isEnabled, isLocked, isResizable, isRightClickable, isRotatable, isSelectable, isSelected, isStyleEditable, isTrackable, isVisible, modificationRejected, prepareForPopup, prepareForRemoval, setAzimuth, setConnectable, setDeletable, setDirty, setDisplayName, setDoubleClickable, setDraggable, setEnabled, setFillFocus, setFocus, setLocked, setModification, setResizable, setResizePolicy, setRightClickable, setRotatable, setSelectable, setSelected, setStyle, setStyleEditable, setVisible, startModification, stopModification, translateLocal

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface edu.cnu.mdi.graphics.drawable.IDrawable

getName

Constructor Details

EllipseItem

public EllipseItem(Layer layer,
 double w,
 double h,
 double azimuth,
 Point2D.Double center)

Create an ellipse.

Parameters:

layer - the z layer this item is on.

w - full width in world units (clamped to MIN_SIZE).

h - full height in world units (clamped to MIN_SIZE).

azimuth - rotation in degrees, using the application's compass/bearing convention.

center - ellipse center in world coordinates (copied). If null, the ellipse path is null until focus is set and rebuildPath() is called.

Method Details

reshape

protected void reshape()

Ellipse-specific reshape: update width/height based on which selection handle is dragged.

Handles are:

• 0 = top
• 1 = right
• 2 = bottom
• 3 = left

Important implementation details for stable dragging after rotation:

• Use the start focus as the center for the entire drag to avoid drift.
• Project into ellipse-local coordinates using the same bearing azimuth convention as WorldGraphicsUtils.project(java.awt.geom.Point2D.Double, double, double, java.awt.geom.Point2D.Double).

Overrides:

reshape in class PolygonItem

getSelectionPoints

public Point[] getSelectionPoints(IContainer container)

Return the four selection handles in local (screen) coordinates.

Overrides:

getSelectionPoints in class AItem

Parameters:

container - the container for world→local conversion.

Returns:

a 4-element array of local points, or null if unavailable.

setSize

public void setSize(double w,
 double h)

Programmatically set ellipse size (full extents), clamped to MIN_SIZE.

Parameters:

w - new full width in world units.

h - new full height in world units.

getWidthWorld

public double getWidthWorld()

Returns:

full width in world units.

getHeightWorld

public double getHeightWorld()

Returns:

full height in world units.