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/*

** 这个程序是读取jpg图像的

** 后续加上jpg图像打开和存放

*/ #include

#include

#include

#include

#include #define SOI 0xD8 //文件头

#define EOI 0xD9 //文件尾

#define APP0 0xE0 //定义交换格式和图像识别信息

#define SOF0 0xC0 //帧开始(标准 JPEG)

#define DQT 0xDB //定义量化表

#define DHT 0xC4 //定义 Huffman 表(霍夫曼表)

#define SOS 0xDA // 扫描行开始

#define DRI 0xDD //定义重新开始间隔

#define COM 0xFE //注释 unsigned short jpgWidth; //图像的宽

unsigned short jpgHeight; //图像的高

unsigned char bitDepth; //图像类型，每像素位数

unsigned short jpgXpelsPerMeter; //水平分辨率

unsigned short jpgYpelsPerMeter; //垂直分辨率

unsigned char SOF_find=0; char readPath[100]; //图像路径

unsigned char CurrentByte; //当前字节

unsigned short CurrentWord; //当前word

unsigned int BytePos; //当前字节的位置 bool readjpg(char *jpgName); //读取路径

void showjpg(); //显示

void GetJpgSize(FILE *fp); //获取大小 /****************************分割线**************************************/

bool readjpg(char *jpgName)

{

unsigned char Flag_1,Flag_2; //文件头 FFD8

unsigned short Xdensity,Ydensity;

/*unsigned char SOS_find=0;

unsigned int FileLength;

unsigned char Length;*/

//二进制读方式打开指定的图像文件

FILE *fp;

fp=fopen(jpgName,"rb");

if(fp==0)

{

perror("jpgName"); //提示错误信息

getch();

exit(EXIT_FAILURE); //出现错误，终止程序。

} /*

判断文件类型是否为JPG

检查第1， 2字节

*/

fread(&Flag_1,1,1,fp);

fseek(fp,1L,0);

fread(&Flag_2,1,1,fp);

if(( Flag_1 != 0xff) || (Flag_2 != 0xd8) )

{

printf("Not a jpg file?? (SOI)\n");

exit(EXIT_FAILURE);

}

//开始寻找开始位置

GetJpgSize(fp); fclose(fp);

return 1;

} void showjpg()

{

//窗口大小为图片大小

initgraph(jpgWidth,jpgHeight+40);

setbkcolor(WHITE);

setcolor(BLACK);

cleardevice(); setfont(16, 8, "宋体");

char width[5],height[5];

sprintf(width, "%d",jpgWidth);

sprintf(height, "%d",jpgHeight); outtextxy(0,0,"图像的宽:");

outtextxy(10+textwidth("图像的宽:"),0,width); outtextxy(jpgWidth/2,0,"图像的高:");

outtextxy(jpgWidth/2 + 10 + textwidth("图像的高"),0,height); IMAGE img; // 定义 IMAGE 对象

loadimage(&img, readPath); //读取图片到 img 对象中

putimage(0, 40, &img); // 在坐标 (0, 0) 位置显示 IMAGE 对象 getch();

closegraph();

} //获取照片尺寸大小

void GetJpgSize(FILE *fp)

{ unsigned char HeightH;

unsigned char HeightL;

unsigned char WidthH;

unsigned char WidthL;

unsigned char BitDepth;

while(!SOF_find)

{

CurrentByte=fgetc(fp);

if(CurrentByte!=0xFF)

continue;

//发现标记符

CurrentByte=fgetc(fp);

switch(CurrentByte)

{

case APP0: break;

case SOF0:

fseek(fp,2L,1); BitDepth=fgetc(fp); //图像高的高位和低位

HeightH=fgetc(fp); HeightL=fgetc(fp); //图像宽的高位和低位

WidthH=fgetc(fp); WidthL=fgetc(fp); SOF_find=1;

break;

default:

break;

}

}

jpgHeight=HeightH * 256 + HeightL;

jpgWidth=WidthH * 256 + WidthL; } void main()

{

printf("输入图像的完整路径及文件名:\n");

gets(readPath);

readjpg(readPath);

printf(" bitDepth=%x\n height=%x\n width=%x\n ",bitDepth,jpgHeight,jpgWidth);

printf(" jpgXpelsPerMeter=%x\n jpgYpelsPerMeter=%x\n",jpgXpelsPerMeter,jpgYpelsPerMeter); printf("按任意键显示图像\n");

getch();

showjpg();

}