#include <stdio.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <linux/fb.h>

#include <sys/mman.h>

#include <string.h>

#include <stdlib.h>

/*

可编程信息

struct fb_var_screeninfo {

  __u32 xres;           //x轴像素点数量

  __u32 yres;            //y轴像素点数量

  __u32 xres_virtual;   //虚拟屏x轴

  __u32 yres_virtual;   //虚拟屏y轴

  __u32 xoffset;

  __u32 yoffset;

  __u32 bits_per_pixel;    //色深

  __u32 grayscale;

  struct fb_bitfield red;    //fb缓存的R\G\B位域

  struct fb_bitfield green;

  struct fb_bitfield blue;

  struct fb_bitfield transp;

  __u32 nonstd;

  __u32 activate;

  __u32 height;            //屏幕的高度

  __u32 width;            //屏幕的宽度

  __u32 accel_flags;

  __u32 pixclock;

  __u32 left_margin;

  __u32 right_margin;

  __u32 upper_margin;

  __u32 lower_margin;

  __u32 hsync_len;

  __u32 vsync_len;

  __u32 sync;

  __u32 vmode;

  __u32 rotate;

  __u32 colorspace;

  __u32 reserved[4];

};

固定信息

struct fb_fix_screeninfo {

  char id[16];                //标识符

  unsigned long smem_start; //fb缓存的起始位置

  __u32 smem_len;            //fb缓存的大小

  __u32 type;

  __u32 type_aux;

  __u32 visual;

  __u16 xpanstep;

  __u16 ypanstep;

  __u16 ywrapstep;

  __u32 line_length;

  unsigned long mmio_start;    //内存映射I/O的开始位置

  __u32 mmio_len;            //内存映射I/O的长度

  __u32 accel;

  __u16 capabilities;

  __u16 reserved[2];

}

*/

char *fb_addr;

unsigned fb_size;

void print_screen(char *buf,int width,int height);

int main(int argc,char *argv[])

{

    int fd=;

    struct fb_fix_screeninfo fb_fix;

    struct fb_var_screeninfo fb_var;

    char *env=NULL;

    short *picture;

    int ret;

    env="/dev/graphics/fb0";

    //env="/sys/class/graphics/fb0";

    fd=open(env,O_RDWR);

    printf("aplex test v2 \n");

    printf("fd= %s\n",env);

    ioctl(fd,FBIOGET_FSCREENINFO,&fb_fix);

    printf("fb_fix.line_length=%u\n",fb_fix.line_length);

    printf("fb_fix.accel=%u\n",fb_fix.accel);

    ioctl(fd,FBIOGET_VSCREENINFO,&fb_var);

    printf("fb_var.xres=%u\n",fb_var.xres);

    printf("fb_var.yres=%u\n",fb_var.yres);

    printf("fb_var.xres_virtual=%u\n",fb_var.xres_virtual);

    printf("fb_var.yres_virtual=%u\n",fb_var.yres_virtual);

    fb_size=fb_var.yres*fb_fix.line_length;

    /*fb_addr的获取，是很核心的步骤，表示成功获得了framebuffer设备*/

    fb_addr=(char *)mmap(NULL,fb_size,PROT_READ|PROT_WRITE,MAP_SHARED,fd,);

    picture=(char *)malloc(fb_var.yres*fb_fix.line_length);

    memset(picture,0xFF,fb_var.yres*fb_fix.line_length);

            /*注意，这里对颜色的赋值只是一次赋一半值，也就是一个字节，8bit*/

            /*而事实上，一个像素的颜色值是16bit*/

            /*0xFFFF就是白色*/

            /*介绍一下16bit的颜色的类型，颜色是由RGB组成,如果是565排列,

            则依次为Red Green Blue

                    11111 111111 11111

                                           */

    print_screen(picture,fb_var.xres,fb_var.yres);

    return ;

}

void print_screen(char *buf,int width,int height)

{

    short *t_data=(short *)buf;

    short *t_fb_addr=(short *)fb_addr;

    int bytew=width<<; /*像素数乘以2即是字节数，因为颜色深度是2个字节(16bit)*/

    while(--height>=)

    {

       memcpy(t_fb_addr,t_data,bytew); /*一行的数据赋值*/

       t_fb_addr += width;

       t_data += width;

    }

}

root@sabresd_6dq:/data # ./frameworkTest

aplex test v2

fd= /dev/graphics/fb0

fb_fix.line_length=

fb_fix.accel=

fb_var.xres=

fb_var.yres=

fb_var.xres_virtual=

fb_var.yres_virtual=