在Framebuffer下编程显示BMP图象 分享

http://yaos.blog.sohu.com/20240931.html

今天看别人的代码，知道可以使控制台进入图形模式，这样SHELL程序的显示就不会影响BMP图像的显示了。于是，COPY过来，放入自己先前的那个程序，再整个800x600的BMP图，试试全屏显示的效果！爽^0^爽

/*
   showbmp.c
   allenyao 2006/11/10

*/
#include
#include
#include
#include
#include
#include
#include /*新添加的，用于进行图形模式时ioctl使用*/
#include
#include
#include

typedef struct
{
  char cfType[2];         /* 文件类型, 必须为 "BM" (0x4D42) */
  char cfSize[4];         /* 文件的大小(字节) */
  char cfReserved[4];     /* 保留, 必须为 0 */
  char cfoffBits[4];      /* 位图阵列相对于文件头的偏移量(字节) */
} BITMAPFILEHEADER;       /* 文件头结构 */

typedef struct
{
  char ciSize[4];         /* size of BITMAPINFOHEADER */
  char ciWidth[4];        /* 位图宽度(像素) */
  char ciHeight[4];       /* 位图高度(像素) */
  char ciPlanes[2];       /* 目标设备的位平面数, 必须置为1 */
  char ciBitCount[2];     /* 每个像素的位数, 1,4,8或24 */
  char ciCompress[4];     /* 位图阵列的压缩方法,0=不压缩 */
  char ciSizeImage[4];    /* 图像大小(字节) */
  char ciXPelsPerMeter[4];/* 目标设备水平每米像素个数 */
  char ciYPelsPerMeter[4];/* 目标设备垂直每米像素个数 */
  char ciClrUsed[4];      /* 位图实际使用的颜色表的颜色数 */
  char ciClrImportant[4]; /* 重要颜色索引的个数 */
} BITMAPINFOHEADER;       /* 位图信息头结构 */

typedef struct
{
  char rgbBlue;
  char rgbGreen;
  char rgbRed;
  char rgbReserved;
} RGBQUAD;

BITMAPFILEHEADER FileHead;
BITMAPINFOHEADER InfoHead;
RGBQUAD rgbquad;

char *fbp = 0;
int xres = 0;
int yres = 0;
int bits_per_pixel = 0;
int tty;
int tty_mode_was;

int set_tty_graphics( void );
int set_tty_text( void );
int  show_bmp  ( char *bmpfile );
long chartolong( char * string, int length );
/******************************************************************************
 *
 ******************************************************************************/
int main( int argc, char *argv[] )
{
    int fbfd = 0;
    struct fb_var_screeninfo vinfo;
    struct fb_fix_screeninfo finfo;
    long int screensize = 0;

    // Open the file for reading and writing
    fbfd = open("/dev/fb0", O_RDWR);
    if (!fbfd)
    {
        printf("Error: cannot open framebuffer device.\n");
        exit(1);
    }

    // Get fixed screen information
    if (ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo))
    {
        printf("Error reading fixed information.\n");
        exit(2);
    }

    // Get variable screen information
    if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo))
    {
        printf("Error reading variable information.\n");
        exit(3);
    }

    printf("%dx%d, %dbpp\n", vinfo.xres, vinfo.yres, vinfo.bits_per_pixel );
    xres = vinfo.xres;
    yres = vinfo.yres;
    bits_per_pixel = vinfo.bits_per_pixel;

    // Figure out the size of the screen in bytes
    screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;

    // Map the device to memory
    fbp = (char *)mmap(0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED,
                       fbfd, 0);
    if ((int)fbp == -1)
    {
        printf("Error: failed to map framebuffer device to memory.\n");
        exit(4);
    }

 if (set_tty_graphics())
 {
  show_bmp( argv[1] );
 }
 sleep( 10 );
 set_tty_text();
 
    munmap(fbp, screensize);
    close(fbfd);
    return 0;
}

/******************************************************************************
 *
 ******************************************************************************/
int show_bmp( char *bmpfile )
{
 FILE *fp;
 int rc;
 int ciBitCount, ciWidth, ciHeight;
 int line_x, line_y;
 long int location = 0, BytesPerLine = 0;
 char tmp[1024*10];
  
 /* 打开位图文件 */
 fp = fopen( bmpfile, "rb" );
 if (fp == NULL)
 {
  return( -1 );
 }
 
 /* 读取位图文件头 */
 rc = fread( &FileHead, 1, sizeof(BITMAPFILEHEADER), fp );
 if ( rc != sizeof( BITMAPFILEHEADER ) )
 {
  fclose( fp );
  return( -2 );
 }
 
 /* 判断位图的类型 */
 if (memcmp(FileHead.cfType, "BM", 2) != 0)
 {
  fclose( fp );
  return( -3 );
 }

 /* 读取位图信息头 */
 rc = fread( (char *)&InfoHead, 1, sizeof(BITMAPINFOHEADER), fp );
 if ( rc != sizeof(BITMAPINFOHEADER) )
 {
  fclose( fp );
  return( -4 );
 }
 
 ciWidth    = (int) chartolong( InfoHead.ciWidth,    4 );
 ciHeight   = (int) chartolong( InfoHead.ciHeight,   4 );
 ciBitCount = (int) chartolong( InfoHead.ciBitCount, 4 );
 
 line_x = line_y = 0;
 /*
 while( !feof( fp ) )
 {
  rc = fread( (char *)&rgbquad, 1, sizeof(RGBQUAD), fp );
  if ( rc != sizeof(RGBQUAD) )
  {
   break;
  }

  location = line_x * bits_per_pixel / 8 + (ciHeight - line_y - 1) * xres * bits_per_pixel / 8;

  *(fbp + location) = rgbquad.rgbBlue;
  *(fbp + location + 1) = rgbquad.rgbGreen;
  *(fbp + location + 2) = rgbquad.rgbRed;
  *(fbp + location + 3) = rgbquad.rgbReserved;
 
  line_x++;
  if ( line_x == ( ciWidth - 1 ) )
  {
   line_x = 0;
   line_y++;
  }
 }
 */
 BytesPerLine = (ciWidth * ciBitCount + 31) / 32 * 4;
 
 while( !feof( fp ) )
 {
  rc = fread( tmp, 1, BytesPerLine, fp );
  if ( rc != BytesPerLine )
  {
   break;
  }
 
  location = (ciHeight - line_y - 1) * xres * bits_per_pixel / 8;
  memcpy( (fbp + location) , tmp, BytesPerLine );

  line_y++;
 }
 fclose( fp );
 return( 0 );
}

/******************************************************************************
 *
 ******************************************************************************/
long chartolong( char * string, int length )
{
 long number;
 
 if (length <= 4)
 {
  memset( &number, 0x00, sizeof(long) );
  memcpy( &number, string, length );
 }
 
 return( number );
}

/******************************************************************************
 *
 ******************************************************************************/
int set_tty_graphics( void )
{
    int ret = 1;

    if(0 > (tty = open("/dev/tty0", O_RDWR)))
    {
        printf( "ERROR: /dev/tty0 open failed\n" );
        ret = 0;
    }
    else if(0 > ioctl(tty, KDGETMODE, &tty_mode_was))
    {
        printf( "ERROR: /dev/tty0 get mode failed\n");
        close(tty);
        ret = 0;
    }
    else if((KD_GRAPHICS != tty_mode_was)
             && (0 > ioctl(tty, KDSETMODE, KD_GRAPHICS)))
    {
        printf( "ERROR: /dev/tty0 set graphics failed\n");
        close(tty);
        ret = 0;
    }
    else
    {
        printf("tty mode was ");
        switch(tty_mode_was)
        {
            case KD_TEXT     :  printf("KD_TEXT"     ); break;
            case KD_GRAPHICS :  printf("KD_GRAPHICS" ); break;
            default          :  printf("IMPOSSIBLE!" ); break;
        }
        printf("\n");
        printf("tty mode set to KD_GRAPHICS\n");
        fflush(stdout);
        close(tty);
    }
 return( ret );
}

/******************************************************************************
 *
 ******************************************************************************/
int set_tty_text( void )
{
 int ret = 1;

    if(0 > (tty = open("/dev/tty0", O_RDWR)))
    {
        printf( "ERROR: /dev/tty0 open failed\n" );
        ret = 0;
    }
    else if(0 > ioctl(tty, KDSETMODE, tty_mode_was))
    {
        printf( "ERROR: /dev/tty0 reset mode failed\n");
        close(tty);
        ret = 0;
    }
    else
    {
        printf("tty mode set to ");
        switch(tty_mode_was)
        {
            case KD_TEXT     :  printf("KD_TEXT"     ); break;
            case KD_GRAPHICS :  printf("KD_GRAPHICS" ); break;
            default          :  printf("IMPOSSIBLE!" ); break;
        }
        printf("\n");
        fflush(stdout);
        close(tty);
    }
 return( ret );
}

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