【AT91SAM3S】SAM3S-EK Demo工程中，LCD驱动程序的加载(函数指针结构体)
为了调试LCD，，在英倍特的板子上烧Atmel的sam3s-ek_demo_1.4_source示例代码.LCD显示正常了，却找不到LCD的驱动究竟在哪。
花了好久，追踪到了这个执行过程。
进入main函数–_SetupHardware()—-DISP_Initialize() —-_aDISP_Backends[DISP_BACKEND_ILI9325]=&sDISP_Backend_ILI9325 ;
static __no_init SDISPBackend* _aDISP_Backends[DISP_BACKEND_MAX] ;
_aDISP_Backends[DISP_BACKEND_ILI9325]=&sDISP_Backend_ILI9325 ;
然后就是结构体：
SDISPBackend是一个函数指针结构体。其定义是这样的：
typedef struct _SDISPBackendData{uint32_t dwID ;uint32_t dwOrientation ; // Portrait, Landscapeuint32_t dwMode ; // RGB, BGR} sDISPBackendData ;
typedef struct _SDISPBackend{sDISPBackendData sData ;
uint32_t (*Reset)( void ) ;uint32_t (*Initialize)( void ) ;uint32_t (*GetPixel)( uint32_t dwX, uint32_t dwY, SGUIColor* pclrResult ) ;uint32_t (*DrawPixel)( uint32_t dwX, uint32_t dwY, SGUIColor* pclrIn ) ;uint32_t (*DrawLine)( uint32_t dwX1, uint32_t dwY1, uint32_t dwX2, uint32_t dwY2, SGUIColor* pclrIn ) ;uint32_t (*DrawCircle)( uint32_t dwX, uint32_t dwY, uint32_t dwRadius, SGUIColor* pclrBorder ) ;uint32_t (*DrawFilledCircle)( uint32_t dwX, uint32_t dwY, uint32_t dwRadius, SGUIColor* pclrBorder, SGUIColor* pclrInside ) ;uint32_t (*DrawRectangle)( uint32_t dwX1, uint32_t dwY1, uint32_t dwX2, uint32_t dwY2, SGUIColor* pclrFrame ) ;uint32_t (*DrawFilledRectangle)( uint32_t dwX1, uint32_t dwY1, uint32_t dwX2, uint32_t dwY2, SGUIColor* pclrFrame, SGUIColor* pclrInside ) ;uint32_t (*DrawBitmap)( uint32_t dwX, uint32_t dwY, uint32_t dwWidth, uint32_t dwHeight, uint8_t* pucData ) ;uint32_t (*DrawText)( uint32_t dwX, uint32_t dwY, uint8_t* pszText, SGUIColor* pclrText, SGUIFont* pFont, uint32_t dwSize ) ;uint32_t (*Fill)( uint32_t dwX, uint32_t dwY, SGUIColor* pclrIn ) ;uint32_t (*IOCtl)( uint32_t dwCommand, uint32_t* pdwValue, uint32_t* pdwValueLength ) ;} SDISPBackend ;
使用下面这个函数将后端的代码跟前端的使用映射在一起：
SDISPBackend sDISP_Backend_ILI9325={ .sData= { .dwID=DISP_BACKEND_ILI9325, },
.Reset=_DBE_ILI9325_Reset, .Initialize=_DBE_ILI9325_Initialize, .GetPixel=_DBE_ILI9325_GetPixel, .DrawPixel=_DBE_ILI9325_DrawPixel, .DrawLine=_DBE_ILI9325_DrawLine, .DrawCircle=_DBE_ILI9325_DrawCircle, .DrawFilledCircle=_DBE_ILI9325_DrawFilledCircle, .DrawRectangle=_DBE_ILI9325_DrawRectangle, .DrawFilledRectangle=_DBE_ILI9325_DrawFilledRectangle, .DrawBitmap=_DBE_ILI9325_DrawBitmap, .DrawText=_DBE_ILI9325_DrawText, .Fill=NULL, .IOCtl=_DBE_ILI9325_IOCtl} ;使用时，直接调用sDISP_Backend_ILI9325.Initialize之类的函数就可以了。
感叹：C语言用到这个地步，已远非我所能够模仿的了。
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不会因为忧伤而风情万种。
