Package edu.cnu.mdi.mapping.item

Class AMapItem

java.lang.Object

edu.cnu.mdi.item.AItem

edu.cnu.mdi.mapping.item.AMapItem

All Implemented Interfaces:

IFeedbackProvider, IDrawable, EventListener

Direct Known Subclasses:

AMapMultiPointItem, MapLineItem, MapPointItem, MapTextItem

public abstract class AMapItem
extends AItem

Abstract base class for map-native items whose geometry is stored in geographic coordinates (longitude/latitude in radians) rather than in the container's affine-transform world coordinate system.

Coordinate convention

All geographic points follow the MDI mapping convention: a Point2D.Double where x = λ (longitude) and y = φ (latitude), both in radians. Longitude is wrapped to the half-open range (-π, π].

Focus semantics

The AItem._focus field inherited from AItem is repurposed to hold a geographic point rather than a world (projection-space) point. Subclasses are responsible for keeping _focus updated (typically in updateFocus()) to a meaningful geographic reference point such as the arc midpoint or the polygon centroid.

Screen-space focus

getFocusPoint(IContainer) is overridden to convert the geographic focus through the active map projection rather than through the container's plain affine transform. If the container is not a MapContainer, or if the geographic focus projects to a non-finite point (e.g. the far hemisphere on an orthographic projection), the method returns null.

Subclass responsibilities

• Store geometry in geographic coordinates (radians).
• Override updateFocus() to keep AItem._focus current.
• Override AItem.drawItem(java.awt.Graphics2D, edu.cnu.mdi.container.IContainer), AItem.shouldDraw(java.awt.Graphics2D, edu.cnu.mdi.container.IContainer), AItem.contains(edu.cnu.mdi.container.IContainer, java.awt.Point), AItem.getBounds(edu.cnu.mdi.container.IContainer), and AItem.translateWorld(double, double) to operate in geographic space.

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
AMapItem(Layer layer, Object... keyVals)	Constructs a new map item on the given layer.

Method Summary

Modifier and Type	Method	Description
Point	getFocusPoint(IContainer container)	Returns the screen-coordinate pixel position of this item's geographic focus point.
protected void	updateFocus()	Hook called when geometry changes and the geographic focus should be recomputed.

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

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

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

AMapItem

public AMapItem(Layer layer,
 Object... keyVals)

Constructs a new map item on the given layer.

Parameters:

layer - the layer this item belongs to; must not be null

keyVals - optional alternating PropertyUtils key/value pairs applied to behavior flags and style

Method Details

getFocusPoint

public Point getFocusPoint(IContainer container)

Returns the screen-coordinate pixel position of this item's geographic focus point.

The conversion path is: geographic focus → projection-space (x, y) via the active IMapProjection → device pixels via BaseContainer.worldToLocal.

Returns null if:

• container is not a MapContainer,
• the geographic focus is null, or
• the focus projects to a non-finite coordinate (e.g. behind the globe in an orthographic projection).

Overrides:

getFocusPoint in class AItem

Parameters:

container - the container rendering this item

Returns:

the device-space focus position, or null

updateFocus

protected void updateFocus()

Hook called when geometry changes and the geographic focus should be recomputed.

The default implementation is a no-op. Subclasses that maintain a derived focus (e.g. the geodesic midpoint of a great-circle arc, or the geographic centroid of a polygon) should override this to recompute AItem._focus from the current geometry.

Overrides:

updateFocus in class AItem