Package edu.cnu.mdi.mapping.item

Class MapPolygonItem

java.lang.Object

edu.cnu.mdi.item.AItem

edu.cnu.mdi.mapping.item.AMapItem

edu.cnu.mdi.mapping.item.AMapMultiPointItem

edu.cnu.mdi.mapping.item.MapPolygonItem

All Implemented Interfaces:

IFeedbackProvider, IDrawable, EventListener

public class MapPolygonItem
extends AMapMultiPointItem

A map-native closed spherical polygon defined by an ordered array of geographic vertices, with every edge (including the closing edge from the last vertex back to the first) rendered as a great-circle arc.

Use cases

User-drawn region boundaries, search areas, territorial outlines, or any closed shape whose vertices must remain geographically pinned when the projection changes.

Drawing model — closed polyline, not Path2D.closePath()

All N edges (including the closing edge vertex[N-1] → vertex[0]) are sampled as great-circle arcs by passing a length-(N+1) vertex array (vertex[0] duplicated at the end) to MapGraphics.buildProjectedPolyline(edu.cnu.mdi.mapping.container.MapContainer, java.awt.geom.Point2D.Double[]). This means:

• Every edge is a proper great-circle arc — no straight chord appears for the closing edge.
• Path2D.closePath() is never called, so seam-split sub-paths are not incorrectly filled with a straight closing line.
• The shape is drawn via MapGraphics.drawMapPolyline(Graphics2D, MapContainer, Point2D.Double[], edu.cnu.mdi.graphics.style.IStyled) with fill handled separately as a pre-pass.

Hit-testing

Because seam splitting produces multiple disconnected sub-paths, Java2D's Path2D.contains(double, double) cannot reliably test interior containment for the full polygon. Instead, a spherical ray-casting test is applied directly to the geographic AMapMultiPointItem._latLons array, which is both projection-independent and exact. The test counts how many great-circle edges the meridian from the test point north to the pole crosses; an odd count means the point is inside.

Interaction

• Drag — moves all vertices by the geographic delta of the mouse.
• Resize — moves the grabbed handle vertex to the cursor.
• Rotate — not supported (see AMapMultiPointItem).

Nested Class Summary

Nested classes/interfaces inherited from class edu.cnu.mdi.mapping.item.AMapMultiPointItem

AMapMultiPointItem.MultiPointStartState

Field Summary

Fields inherited from class edu.cnu.mdi.mapping.item.AMapMultiPointItem

_latLons, _projectedShape

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
MapPolygonItem(Layer layer, Point2D.Double[] latLons)	Creates a map-native spherical polygon.
MapPolygonItem(Layer layer, Point2D.Double[] latLons, Object... keyVals)	Creates a map-native spherical polygon with optional property key/value pairs.

Method Summary

Modifier and Type	Method	Description
protected MapGraphics.ProjectedMapShape	buildShape(MapContainer mc)	Build the projected shape from the current vertices.
protected boolean	containsPoint(MapGraphics.ProjectedMapShape shape, Point screenPoint)	Tests whether a screen point hits the projected shape.
void	drawItem(Graphics2D g2, IContainer container)	Draws the closed spherical polygon.

Methods inherited from class edu.cnu.mdi.mapping.item.AMapMultiPointItem

contains, copyVertices, ensureProjectedShape, getBounds, getFeedbackStrings, getLatLons, getSelectionPoints, getVertexCount, getWorldBounds, localToLatLon, modify, prepareForRemoval, projectLatLon, setDirty, setLatLons, shouldDraw, startModification, translateWorld, updateFocus

Methods inherited from class edu.cnu.mdi.mapping.item.AMapItem

getFocusPoint

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

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

MapPolygonItem

public MapPolygonItem(Layer layer,
 Point2D.Double[] latLons)

Creates a map-native spherical polygon.

Parameters:

layer - the layer; must not be null

latLons - geographic vertices in radians (x = longitude, y = latitude); must not be null, length ≥ 3

Throws:

IllegalArgumentException - if latLons has fewer than 3 points

MapPolygonItem

public MapPolygonItem(Layer layer,
 Point2D.Double[] latLons,
 Object... keyVals)

Creates a map-native spherical polygon with optional property key/value pairs.

Parameters:

layer - the layer; must not be null

latLons - geographic vertices in radians; must not be null, length ≥ 3

keyVals - optional PropertyUtils key/value pairs

Throws:

IllegalArgumentException - if latLons has fewer than 3 points

Method Details

drawItem

public void drawItem(Graphics2D g2,
 IContainer container)

Draws the closed spherical polygon.

Fill (if any) is painted first using a true projected polygon shape (correct interior semantics even across seam splits), then the outline is drawn as a closed polyline of great-circle arcs so that the closing edge is a genuine arc rather than a straight chord. A separate outline shape is cached in _projectedShape for bounds/edge hit-testing.

Specified by:

drawItem in class AItem

Parameters:

g2 - the graphics context

container - the rendering container; must be a MapContainer

containsPoint

protected boolean containsPoint(MapGraphics.ProjectedMapShape shape,
 Point screenPoint)

Tests whether a screen point hits the projected shape.

Default: 6-pixel proximity (correct for open polylines). MapPolygonItem overrides to also test interior containment.

Interior containment is tested using a spherical ray-casting algorithm on the geographic AMapMultiPointItem._latLons array, so the result is correct regardless of how the projection splits the boundary into sub-paths. Outline proximity (6-pixel tolerance) is tested as a fallback so the boundary is always clickable even for unfilled polygons.

Overrides:

containsPoint in class AMapMultiPointItem

Parameters:

shape - projected shape (may be null)

screenPoint - device-space test point

Returns:

true if the point hits the shape

buildShape

protected MapGraphics.ProjectedMapShape buildShape(MapContainer mc)

Build the projected shape from the current vertices.

Use MapGraphics.buildProjectedPolyline(edu.cnu.mdi.mapping.container.MapContainer, java.awt.geom.Point2D.Double[]) for open items, MapGraphics.buildProjectedPolygon(edu.cnu.mdi.mapping.container.MapContainer, java.awt.geom.Point2D.Double[]) for closed items.

Builds an open polyline of the N+1 closed-polygon vertices (vertex[0] duplicated at the end) so that all edges, including the closing edge, are great-circle arcs. Path2D.closePath() is not used.

Specified by:

buildShape in class AMapMultiPointItem

Parameters:

mc - the owning map container

Returns:

projected shape; never null