WCPolyTool.h

This class adds to its base WCTool to provide a tool for drawing, reshaping and moving polygons on a WorldCanvas. While WCPolyTool is not abstract, it performs no useful function. The programmer should derive from this class and override the functions doubleInside and doubleOutside at the very least. These are called when the user double-clicks a particular key or mouse button inside or outside an existing polygon respectively. It is up to the programmer to decide what these events mean, but it is recommended that an internal double- click correspond to the main action of the tool, eg. emitting the polygon vertices to the application, and that an external double-click correspond to a secondary action of the tool, if indeed there are additional actions suitable to the tool.

The polygon is drawn by clicking at each of the vertices, and clicking on the last or first vertices to complete the polygon. Once drawn, the vertices can be moved by dragging their handles, and the entire polygon relocated by dragging inside the polygon. The polygon is removed from the display when the Esc key is pressed.

Example

Motivation

Many activities on the WorldCanvas will be based on the user drawing a polygon and using the polygon in some operation.

To Do

Add time constraint to double click detection

Member Description

WCPolyTool(WorldCanvas *wcanvas, Display::KeySym keysym = Display::K_Pointer_Button1, const Bool persistent = False)

Constructor

virtual ~WCPolyTool()

Destructor

virtual void disable()

Switch the tool off - this calls the base class disable, and then erases the polygon if it's around

virtual void keyPressed(const WCPositionEvent &ev)
virtual void keyReleased(const WCPositionEvent &ev)
virtual void otherKeyPressed(const WCPositionEvent &ev)
virtual void moved(const WCMotionEvent &ev)
virtual void refresh(const WCRefreshEvent &ev)

Functions called by the local event handling operators - these handle the drawing of the polygon. In special conditions, namely double clicking the key, they will pass control on to the doubleInside and doubleOutside functions

virtual void doubleInside()
virtual void doubleOutside()

Functions special to the polygon event handling - called when there is a double click inside/outside the polygon

virtual void polygonReady()
virtual void polygonNotReady()

Functions called when a polygon is ready and not being editted, and when this status changes

virtual void get(Vector<Int> &x, Vector<Int> &y)

Retrive the polygon vertices

enum AdjustMode

adjustment mode

void pushPoint(uInt x1, uInt y1)
void popPoint()

Point operations

void preserve()
void restore()

preserve/restore the world coordinates

void draw(Bool drawHandles = False)

draw the polygon on a PixelCanvas

void reset()

reset this drawer

Bool inHandle(const uInt &pt, const uInt &x, const uInt &y) const

are we within the specified handle?

Bool inPolygon(const uInt &x, const uInt &y) const

are we inside the polygon?