基于S3c244016位24位的BMP图片显示程序

wuquan-1230

基于S3c244016位24位的BMP图片显示程序 [复制链接]

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <linux/fb.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>

/***************************************************
*      BMP文件信息头结构
***************************************************/
//14byte
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)*/
}__attribute__((packed)) BITMAPFILEHEADER;       /* 文件头结构 */

//40byte
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
{
  unsigned char blue;
  unsigned char green;
  unsigned char red;
}  PIXEL;
/****************************************************/
BITMAPFILEHEADER FileHead;
BITMAPINFOHEADER InfoHead;

char *fbp = 0;
int xres = 0;
int yres = 0;
int bits_per_pixel = 0;
     
int  put_to_framebuf  ( 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;
/***********************************************************帧缓存相关的*/
    // 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);
    }
printf("sizeof header=%d\n", sizeof(BITMAPFILEHEADER));
printf("into show_bmp fun\n");
/*******************************************************************************/
   int i;
   for(i = 1; i < sizeof(argv);i++){
      put_to_framebuf( argv );      //显示图像
      if(argc != 2)             //判断如果只有一张图片则不进行延时
   sleep(1);
}
    munmap(fbp, screensize);
    close(fbfd);
    return 0;
}

/******************************************************************************
*name    :  put_to_framebuffers
*参数介绍 :  line_x,line_y是坐标偏移量;
        start_x,start_y是数据写入计数器;
        addr_x,addr_y,是写入数据的地址;
功能    :  将一个24位的图片显示在显示屏上
返回值   :  无
time    :  2010.7.21
******************************************************************************/
int put_to_framebuf( char *bmpfile )
{
        FILE *fp;
        int rc;
        int ciBitCount, ciWidth, ciHeight,cfoffBits;
        int line_x, line_y,start_x,start_y,addr_x,addr_y;
        long int location = 0 ;
        
        /* 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, sizeof(BITMAPFILEHEADER),1, fp );
        if ( rc != 1){
      printf("read header error!\n");
            fclose( fp );
            return( -2 );
        }
        /* 判断位图的类型 */
        if (memcmp(FileHead.cfType, "BM", 2) != 0){
      printf("it's not a BMP file\n");
            fclose( fp );
            return( -3 );
        }

        /* 读取位图信息头 */
        rc = fread( (char *)&InfoHead, sizeof(BITMAPINFOHEADER),1, fp );
        if ( rc != 1){
      printf("read infoheader error!\n");
            fclose( fp );
            return( -4 );
        }
    /*将数组中的数连接成32位的数*移位实现*/
        ciWidth    =  InfoHead.ciWidth[3]<<24 |InfoHead.ciWidth[2]<<16 | \
                  InfoHead.ciWidth[1]<<8 |InfoHead.ciWidth[0];
                  
        ciHeight   =  InfoHead.ciHeight[3]<<24|InfoHead.ciHeight[2]<<16| \
                  InfoHead.ciHeight[1]<<8|InfoHead.ciHeight[0];
                   
        ciBitCount =  InfoHead.ciBitCount[3]<<24|InfoHead.ciBitCount[2]<<16| \
                   InfoHead.ciBitCount[1]<<8|InfoHead.ciBitCount[0];
    
    cfoffBits  = FileHead.cfoffBits[3]<<24|FileHead.cfoffBits[2]<<16| \
               FileHead.cfoffBits[1]<<8|FileHead.cfoffBits[0];
    /*也可使用内存复制实现数据的转换***************//*
     ciWidth    = (int) chartolong( InfoHead.ciWidth,    4 );
        ciHeight   = (int) chartolong( InfoHead.ciHeight,   4 );
        ciBitCount = (int) chartolong( InfoHead.ciBitCount, 4 );*/
 
 fseek(fp,  cfoffBits, SEEK_SET);    /*设置偏移量*/     
 printf("width=%d, height=%d, bitCount=%d, offset=%d\n", ciWidth, ciHeight, ciBitCount, (int)chartolong(FileHead.cfoffBits, 4));
       
        if(ciWidth>240&&ciHeight>320){printf("图片过大！无法预览！\n"); return 0;}
       
        if(ciWidth<240||ciHeight<320){   //如果是小图片，则按其尺寸大小在屏幕的中间显示
     line_y = (ciHeight - 320)/2;
     if(ciWidth<=ciHeight)
      line_x = (240 - ciWidth)/2;
     else
      line_x = 0;
    }
    else{
         line_x =0;
     line_y =0;
    }    
     start_x= start_y = 0;
    
 while(!feof(fp))
 {
  PIXEL pix;
  unsigned short int color;
  char rgb[2];

  addr_x = line_x + start_x;
  addr_y = line_y + start_y;
  location = addr_x * bits_per_pixel / 8 + (ciHeight - addr_y - 1) * xres * bits_per_pixel / 8;
  
  if(chartolong(InfoHead.ciBitCount,2) == 24){
   rc = fread( (char *)&pix, 1, 3, fp );
     if (rc != 3 )
     { break; }
   color=(pix.red >>3)<<11 | (pix.green>>2)<<5 | pix.blue>>3;   //将24位的数据转换成十六位565格式
  }
  else if(chartolong(InfoHead.ciBitCount,2) == 16){
     rc = fread( (char *)&rgb,1,2, fp );
     if (rc != 2 )
     { break; }
     color = rgb[0] | rgb[1]<<8;
   }
   
  *((unsigned short int*)(fbp + location)) = color ;
 
  start_x++;
  if (start_x == ciWidth ){
    start_x = 0;
    start_y++;
   
   if(start_y== ciHeight)
   {
    break;
   }
  }
 }

        fclose( fp );
        return( 0 );
}

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