2.4.2电子书fb.c文件

显示层面头文件

定义结构体，为显示统一标准

int (*DeviceInit)(void);

显示类驱动初始化

int (*ShowPixel)(int iPenX, int iPenY, unsigned int dwColor);

对某一点进行瞄色

int (*CleanScreen)(unsigned int dwBackColor);

清屏

int RegisterDispOpr(PT_DispOpr ptDispOpr);

注册相应链表

 

#ifndef _DISP_MANAGER_H
#define _DISP_MANAGER_H

typedef struct DispOpr {
    char *name;
    int iXres;
    int iYres;
    int iBpp;
    int (*DeviceInit)(void);
    int (*ShowPixel)(int iPenX, int iPenY, unsigned int dwColor);
    int (*CleanScreen)(unsigned int dwBackColor);
    struct DispOpr *ptNext;
}T_DispOpr, *PT_DispOpr;

int RegisterDispOpr(PT_DispOpr ptDispOpr);
void ShowDispOpr(void);
int DisplayInit(void);
int FBInit(void);

#endif /* _DISP_MANAGER_H */

书写规范 命名变量 全局为g 结构体为t 指针为p int型为i unsigned 为u 变量名单个单词首字母大写

static int FBDeviceInit(void);
static int FBShowPixel(int iPenX, int iPenY, unsigned int dwColor);
static int FBCleanScreen(unsigned int dwBackColor);

static int g_iFBFD;
struct fb_var_screeninfo g_tVar;    /* Current var */
struct fb_fix_screeninfo g_tFix;    /* Current fix */
static int g_iScreenSize;                    //????′óD?
static unsigned char * g_pucFBMem;
static int g_iLineWidth;
static int g_iPixelWidth;


/* 11?ìò????á11ì?￡? éè??￡?×￠2á */
//gè??? t?á11ì?
static T_DispOpr g_tFBispopr = {
    .name = "fb",
    .DeviceInit = FBDeviceInit();
    .ShowPixel = FBShowPixel();
    .CleanScreen = FBCleanScreen();

};

static int FBDeviceInit(void)
{
    
    g_iFBFD = open("FB_DEVICE_NAME",O_RDWR);
    if(g_iFBFD < 0)
    {
        DBG_PRINTF("can't open FB_DEVICE_NAME 
");
        return -1;
    }
    if(ioctl(g_iFBFD, FBIOGET_VSCREENINFO, &g_tVar))
    {
        DBG_PRINTF("can't get var 
");
        return -1;    
    }
    if(ioctl(g_iFBFD, FBIOGET_FSCREENINFO, &g_tFix))
    {
        DBG_PRINTF("can't get fix 
");
        return -1;    
    }

    g_tFBispopr.iXres = g_tVar.xres;
    g_tFBispopr.iYres = g_tVar.yres;
    g_tFBispopr.iBpp  = g_tVar.bits_per_pixel;
    
    g_iScreenSize = var.xres * var.yres * var.bits_per_pixel / 8;    //μ￥??×??ú
    
    g_pucFBMem = (unsigned char *)mmap(NULL, screen_size, 
        PROT_READ | PROT_WRITE, MAP_SHARED, fd_fb, 0);
    if(g_pucFBMem == (unsigned char *) -1)
    {
        DBG_PRINTF("can't mmap 
");
        return -1;
    }
    memset(g_pucFBMem, 0, g_iScreenSize);

    return 0;
}

static int FBShowPixel(int iPenX, int iPenY, unsigned int dwColor)
{
    unsigned char  *pucPen_8 = g_pucFBMem + iPenY * g_iLineWidth + iPenX * g_iPixelWidth;     //μ±?°??????ó|?ú′?????
    unsigned short *pwPen_16;
    unsigned int   *pdwPen_32;

    unsigned int red, blue, green;
    
    pwPen_16  = (unsigned short *)pucPen_8;
    pdwPen_32 = (unsigned int *)pucPen_8;
    
    switch( g_tFBispopr.iBpp )
    {
        case 8:
        {
            *pucPen_8 = dwColor;            //??ó|μ÷é?°???é?
            
            break;
        }
        case 16:
        {
            /* 5*6*5 */
            red   = (dwColor >> 16) & 0xff;
            green = (dwColor >> 8)  & 0xff;
            blue  = (dwColor >> 0)  & 0xff;

            dwColor = ((red >> 3 ) << 11) | ((green >> 2) << 5) | ( blue >> 3);
            
            /* ??é?êy?Y?a???? */
            *pwPen_16 = dwColor;
            
            break;
        }
        case 32:
        {
            *pdwPen_32 = dwColor;
            
            break;
        }
        
    }
    default:
    {
            DBG_PRINTF("can't surport %dbpp 
", g_tFBispopr.iBpp);
            return -1;
            break;
    }
    return 0;

}

static int FBCleanScreen(unsigned int dwBackColor)
{
    unsigned char  *pucPen_8 = g_pucFBMem;
    unsigned short *pwPen_16;
    unsigned int   *pdwPen_32;
    
    unsigned int red, blue, green;
    int i = 0;

    pwPen_16  = (unsigned short *)pucPen_8;
    pdwPen_32 = (unsigned int *)pucPen_8;
        
    switch( g_tFBispopr.iBpp )
    {
        case 8:
        {
            memset(pucPen_8, dwBackColor, g_iScreenSize);
            
            break;
        }
        case 16:
        {
            /* 5*6*5 */
            red   = (dwBackColor >> 16) & 0xff;
            green = (dwBackColor >> 8)  & 0xff;
            blue  = (dwBackColor >> 0)  & 0xff;

            dwBackColor = ((red >> 3 ) << 11) | ((green >> 2) << 5) | ( blue >> 3);
            for(i = 0 ; i< g_iScreenSize; i++)
            {
                *pwPen_16 = dwBackColor;
                pwPen_16 ++;
                i += 2;
            }
        
            
            break;
        }
        case 32:
        {
            for(i = 0 ; i< g_iScreenSize; i++)
            {
                *pdwPen_32 = dwBackColor;
                pdwPen_32 ++;
                i += 4;
            }            
            break;
        }
        
    }
    default:
    {
            DBG_PRINTF("can't surport %dbpp 
", g_tFBispopr.iBpp);
            return -1;
            break;
    }
    return 0;
    
}

int FBInit(void)
{
    RegisterDispOpr( &g_tFBispopr);
    return 0;
}