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00001 /******************************************************************************** 00002 * * 00003 * B a c k B u f f e r e d C a n v a s W i d g e t * 00004 * * 00005 ********************************************************************************* 00006 * Copyright (C) 2003 by Davy Durham. With coding tips from Jeroen van der Zijp * 00007 ********************************************************************************* 00008 * This library is free software; you can redistribute it and/or * 00009 * modify it under the terms of the GNU Lesser General Public * 00010 * License as published by the Free Software Foundation; either * 00011 * version 2.1 of the License, or (at your option) any later version. * 00012 * * 00013 * This library is distributed in the hope that it will be useful, * 00014 * but WITHOUT ANY WARRANTY; without even the implied warranty of * 00015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * 00016 * Lesser General Public License for more details. * 00017 * * 00018 * You should have received a copy of the GNU Lesser General Public * 00019 * License along with this library; if not, write to the Free Software * 00020 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. * 00021 ********************************************************************************/ 00022 #ifndef FXBACKBUFFEREDCANVAS_H 00023 #define FXBACKBUFFEREDCANVAS_H 00024 00025 #ifndef FXCANVAS_H 00026 #include <fox/FXCanvas.h> 00027 using namespace FX; 00028 #endif 00029 namespace FXEX { 00030 00031 00032 /** 00033 * Back Buffered Canvas, an area drawn by another object, except a little more 00034 * expensive but to reduce flicker 00035 */ 00036 class FXAPI FXBackBufferedCanvas : public FXCanvas { 00037 FXDECLARE(FXBackBufferedCanvas) 00038 00039 private: 00040 FXImage *backBuffer; // the off-screen buffer 00041 FXDC *currentDC; // handle to current FXDC 00042 FXbool inOnPaintEvent; // figure out if we are in a paint event 00043 00044 protected: 00045 /// serialisation 00046 FXBackBufferedCanvas(); 00047 00048 public: 00049 long onPaint(FXObject *sender,FXSelector sel,void *ptr); 00050 long onConfigure(FXObject *sender,FXSelector sel,void *ptr); 00051 00052 public: 00053 /// Construct new back buffered drawing canvas widget 00054 FXBackBufferedCanvas(FXComposite* p,FXObject* tgt=NULL,FXSelector sel=0,FXuint opts=FRAME_NORMAL,FXint x=0,FXint y=0,FXint w=0,FXint h=0); 00055 00056 /// create resources 00057 void create(); 00058 00059 /* 00060 * - This can be used to set the options of the back buffer to include 00061 * IMAGE_OWNED so that the drawing code can call getBackBufferData() 00062 * and render/modify the back buffer. 00063 * - When IMAGE_OWNED is included in the options, then backBuffer->render() 00064 * will be called just before the backbuffer is blitted to the screen. 00065 */ 00066 void setBackBufferOptions(FXint options); 00067 00068 /// return handle to some backbuffered data 00069 void *getBackBufferData(); 00070 00071 /** 00072 * Normally, the user should wait for the SEL_PAINT event to draw the the canvas, in which case 00073 * the ptr parameter would contain the DC to draw to. 00074 * 00075 * However, these two methods need to be used if the user is not waiting for the SEL_PAINT event 00076 * to draw to the canvas since the user should actually be drawing to the back buffer and not the 00077 * actual canvas on screen. (I suppose much more work could be done to make the use of back 00078 * buffering completly transparent and make it have the same interface as FXCanvas) 00079 */ 00080 FXDC *beginPaint(); 00081 00082 /// finish painting 00083 void endPaint(); 00084 00085 /// Save object to stream 00086 virtual void save(FXStream& store) const; 00087 00088 /// Load object from stream 00089 virtual void load(FXStream& store); 00090 00091 /// dtor 00092 virtual ~FXBackBufferedCanvas(); 00093 00094 }; 00095 00096 } // namespace FXEX 00097 #endif // FXBACKBUFFEREDCANVAS_H