飞凌嵌入式ElfBoard-LCD显示图片（bmp）编程示例之编程步骤

FILE *bmp_file = fopen(filename, "rb");

if (!bmp_file) {

perror("Failed to open BMP file");

exit(1);

}

__u32 xres;                     /* visible resolution           */

__u32 yres;

__u32 xres_virtual;             /* virtual resolution           */

__u32 yres_virtual;

__u32 xoffset;                  /* offset from virtual to visible */

__u32 yoffset;                  /* resolution                   */

__u32 bits_per_pixel;           /* guess what                   */

__u32 grayscale;                /* 0 = color, 1 = grayscale,    */

/* >1 = FOURCC                  */

struct fb_bitfield red;         /* bitfield in fb mem if true color, */

struct fb_bitfield green;       /* else only length is significant */

struct fb_bitfield blue;

struct fb_bitfield transp;      /* transparency                 */

__u32 nonstd;                   /* != 0 Non standard pixel format */

__u32 activate;                 /* see FB_ACTIVATE_*            */

__u32 height;                   /* height of picture in mm    */

__u32 width;                    /* width of picture in mm     */

__u32 accel_flags;              /* (OBSOLETE) see fb_info.flags */

/* Timing: All values in pixclocks, except pixclock (of course) */

__u32 pixclock;                 /* pixel clock in ps (pico seconds) */

__u32 left_margin;              /* time from sync to picture    */

__u32 right_margin;             /* time from picture to sync    */

__u32 upper_margin;             /* time from sync to picture    */

__u32 lower_margin;

__u32 hsync_len;                /* length of horizontal sync    */

__u32 vsync_len;                /* length of vertical sync      */

__u32 sync;                     /* see FB_SYNC_*                */

__u32 vmode;                    /* see FB_VMODE_*               */

__u32 rotate;                   /* angle we rotate counter clockwise */

__u32 colorspace;               /* colorspace for FOURCC-based modes */

__u32 reserved[4];              /* Reserved for future compatibility */

};

//若屏幕显示区域大小不合适，可用ioctl(dev_fd, FBIOPUT_VSCREENINFO, &scrinfo)设置

struct fb_var_screeninfo vinfo;

if (ioctl(fb_fd, FBIOGET_VSCREENINFO, &vinfo)) {

perror("Error reading variable information");

close(fb_fd);

return 1;

}

size_t screensize = vinfo->yres_virtual * vinfo->xres_virtual * (vinfo->bits_per_pixel / 8);

uint8_t *fb_ptr = (uint8_t *)mmap(NULL, screensize, PROT_READ | PROT_WRITE, MAP_SHARED, fb_fd, 0);

if (fb_ptr == MAP_FAILED) {

perror("Failed to map framebuffer device to memory");

free(row);

fclose(bmp_file);

return;

}