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casa::WCRefreshEH Class Referenceabstract

Base class for handling WorldCanvas refresh events. More...

#include <WCRefreshEH.h>

Inheritance diagram for casa::WCRefreshEH:
casa::DisplayEH casa::AnimatorRefEH casa::Annotations casa::DDDObject casa::LinkedCursorEH casa::MultiWCTool casa::viewer::RegionToolManager casa::WCToolRefEH casa::WorldCanvasHolder

Public Member Functions

 WCRefreshEH ()
 Default Constructor Required. More...
virtual void operator() (const WCRefreshEvent &ev)=0
 original handler interface (still used for WCRefreshEvents) More...
virtual ~WCRefreshEH ()
 Destructor. More...
- Public Member Functions inherited from casa::DisplayEH
virtual void handleEvent (DisplayEvent &)
 Classes that contain this interface (i.e., derive from it) can override this method to implement actions for whatever types of DisplayEvent they're interested in. More...
virtual ~DisplayEH ()

Detailed Description

Base class for handling WorldCanvas refresh events.



WCRefreshEH : WorldCanvas refresh event-handler


class designed for derivation to provide a standard way of redrawing the screen. To use, derive from this class and implement the () operator. For simple applications, the op () should redraw the screen, or rebuild and redraw all display lists if display lists were used.

More advanced applications should maintain display lists and perhaps cache information at other levels. These kinds of applications should examine the reason field to see what changed so they can minimize the computation needed to redraw the screen. The meanings of the reason field are as follows:

- This is generated only when the user calls refresh() on the canvas.

- This is generated by a change in the colortable distribution. Normally all display lists with color information must be rebuilt and redrawn.

- The world canvas has been resized or repositioned with respect to the pixel canvas, or the pixelCanvas has changed size.

- linear coordinates changed, typically happens when the image is zoomed.

- world coordinates have changed, generally must redraw everything

This class has been modified to inherit interface for handling generic display events as well. (1/02) See DisplayEH for details.


Provide the user with an object-oriented approach to event handling. Allow the user to manage screen refresh in a simplistic way, yet providing information for sophisticated approaches like multi-layer caching.


see the test programs in Display/test.

Definition at line 95 of file WCRefreshEH.h.

Constructor & Destructor Documentation

casa::WCRefreshEH::WCRefreshEH ( )

Default Constructor Required.

virtual casa::WCRefreshEH::~WCRefreshEH ( )


Member Function Documentation

virtual void casa::WCRefreshEH::operator() ( const WCRefreshEvent ev)
pure virtual

The documentation for this class was generated from the following file: