AutoGSave Class Reference

#include <AutoGSave.h>

Public Member Functions
	AutoGSave (IGraphicsPort *graphicsPort)
	~AutoGSave ()

Detailed Description

Automatically calls IGraphicsPort::gsave in constructor and IGraphicsPort::grestore in destructor

so you donot have to explicitly call gsave and grestore. Just create an Object of AutoGSave with

in the scope and you are done.



e.g.

the following code



    InterfacePtr<IGraphicsPort> gPort(gc.GetViewPort(), IID_IGRAPHICSPORT);

    gPort->gsave();

    ...

    gPort->grestore();



would become



    InterfacePtr<IGraphicsPort> gPort(gc.GetViewPort(), IID_IGRAPHICSPORT);

    AutoGSave autoGSave(gPort);

!!! Points to remember while using AutoGSave

  Use AutoGSave only when you have gPort->gsave() and gPort->grestore() in the same scope.

  Do not use AutoGSave when you have some IGraphicsPort call after grestore().



e.g.



{

    port->setrgbcolor(0, 1, 0);

    port->gsave();

    port->setrgbcolor(1, 0, 0);

    port->rectfill(0, 0, 10, 10);

    port->grestore();

    port->rectfill(10, 0, 10, 10);

}



should not be converted to



{

    port->setrgbcolor(0, 1, 0);

    AutoGSave foo(port);

    port->setrgbcolor(1, 0, 0);

    port->rectfill(0, 0, 10, 10);

    port->rectfill(10, 0, 10, 10);

}



As the second call to rectfill will now draw a green rectangle, not a red one as intended.



  Do not forget to remove grestore() from all exit points.



e.g.



   void Foo(IGraphicsPort *port)

   {

       AutoGSave foo(port);

       ...

       if (abort) // whatever

       {

Do NOT call port->grestore() here! return; } ... }

Do not use AutoGSave whenever there are multiple gsave/grestore calls in the same scope. e.g. { gPort->gsave(); ... gPort->grestore(); ... gPort->gsave(); ... gPort->grestore(); }

You should avoid using gsave/grestore (or the AutoGSave utility) excessively - as it can have a dramatic impact on performance and on the quality of exported/printed content. There are no real hard and fast rules about its use, but you shouldn't use it without considering whether you truly need it.

Constructor & Destructor Documentation

AutoGSave::AutoGSave ( IGraphicsPort *  graphicsPort )

inlineexplicit

Constructor

AutoGSave::~AutoGSave ( )

inline

Destructor