读写BMP图像的像素代码,C代码库,德仔网

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【C】读写BMP图像的像素
作者:Dream0303 / 发布于2013/12/26/ 609
#ifndef DLOVE_BMP_H
#define DLOVE_BMP_H

namespace dlove{

typedef unsigned int uint32;
typedef unsigned char uint8;

class Bmp{
 uint32  height;     //高度
 uint32  width;     //宽度
 uint32  size;      //总大小
 uint32  xpelsPerMeter;   //水平分辨率
 uint32  ypelsPerMeter;   //竖直分辨率
 uint8  alignBytes;    //每一行为了是4的倍数而补充的字节
 mutable uint8  rgbs[3];     //getPixelAt()把返回值放在这里,setPixelAt()从这里读取
 uint8  *rgbArray;
 uint32  bytesArow;    //每一行的字节数

public:
 enum Attri{HEIGHT,WIDTH,SIZE,XPELS,YPELS};
 
public:
 Bmp(uint32 width,uint32 height,uint32 xpels,uint32 ypels);
 Bmp(const char *filename);  
 
 ~Bmp();
 
 uint8 *getPixelAt(int x,int y)const;
 void setPixelAt(uint8 *rgbs,int x,int y); 
 
 uint32 get(Attri attr)const;
 void store(const char *storein)const;

private:
 inline static uint8 getAlignBytes(uint32 _width) {
  return 4-(_width*3 & 0x03) & 0x03;
 }//计算每一行像素为了是4的倍数而补加的字节；

 inline uint32 getIndex(int x,int y)const{
  //返回bmp图像上，坐标在(x,y)处的像素点在 rgbArray 中的下标；
  return (height-(++y))*bytesArow+x*3;
 }
};

}


#endif









#include "dloveBmp.h"
#include <stdio.h>
#include <malloc.h>
#include <dlovemacros.h>

using namespace dlove;

Bmp::Bmp(uint32 _width,uint32 _height,uint32 _xpels,uint32 _ypels):
 width(_width),
 height(_height),
 xpelsPerMeter(_xpels),
 ypelsPerMeter(_ypels)
{
 this->alignBytes=( getAlignBytes(_width) );
 this->bytesArow=_width*3+this->alignBytes;

 int bmpPixelSize=this->bytesArow*height;
 this->size=bmpPixelSize+54;
 rgbArray=(uint8*)malloc(bmpPixelSize);
}

#define mReadAttr(attr) \
 fread((void*)&attr,sizeof attr,1,bmpfile);

#define mGoto(index) \
 fseek(bmpfile,index,SEEK_SET);

Bmp::Bmp(const char *filename){
 FILE *bmpfile=fopen(filename,"rb");
 short bitCount;  //图像每个像素的位数
 uint32 compression; //图像的压缩类型
 uint32 pixelSize;  //bmp中像素总大小

 mGoto(0x02);mReadAttr(size);
 mGoto(0x12);mReadAttr(width);mReadAttr(height);
 mGoto(0x1c);mReadAttr(bitCount);mReadAttr(compression);mReadAttr(pixelSize);
 mGoto(0x26);mReadAttr(xpelsPerMeter);mReadAttr(ypelsPerMeter);

 if(compression!=0)
  throw 0x001;
 if(bitCount!=24)
  throw 0x002;

 this->alignBytes=getAlignBytes(this->width);
 this->bytesArow=pixelSize/this->height;

 this->rgbArray=(uint8*)malloc(pixelSize);
 mGoto(0x36);
 fread((void*)rgbArray,sizeof(uint8),pixelSize,bmpfile);

 fclose(bmpfile);
}

Bmp::~Bmp(){
 free(this->rgbArray);
}

uint8* Bmp::getPixelAt(int x,int y)const{
 int index=getIndex(x,y);

// printf("index: %u \n",index); //debug
 for(register int ci(2);ci>=0;--ci,++index)
  *(rgbs+ci)=*(rgbArray+index);

 return rgbs;
}

void Bmp::setPixelAt(uint8 *_rgbs,int x,int y){
 int index=getIndex(x,y)+2;

 for(register int ci=2;ci>=0;--ci,++_rgbs,--index)
  *(rgbArray+index)=*_rgbs;

 return ;
}

uint32 Bmp::get(Attri attri)const{
 switch(attri){
 case WIDTH:return this->width;
 case HEIGHT:return this->height;
 case XPELS:return this->xpelsPerMeter;
 case YPELS:return this->ypelsPerMeter;
 case SIZE:return this->size;
 }
 return -1;
}

#define mDefine(type,num,value) \
 type mLink(attri,num)=value;
#define mWriteNum(num) \
 fwrite((void*)&(mLink(attri,num)),sizeof(mLink(attri,num)),1,bmpfile);
#define mWrite(attr) \
 fwrite((void*)&attr,sizeof attr,1,bmpfile);

void Bmp::store(const char *filename)const{
 FILE *bmpfile=fopen(filename,"wb");
 mDefine(unsigned short,1,0x4d42);
 mDefine(unsigned short,3,0);
 mDefine(unsigned short,4,0);
 mDefine(uint32,5,0x0036);
 mDefine(uint32,6,0x0028);
 mDefine(unsigned short,9,1);
 mDefine(unsigned short,10,0x0018);
 mDefine(uint32,11,0);
 mDefine(uint32,15,0);
 mDefine(uint32,16,0);

 mWriteNum(1);
 mWrite(this->size);
 mWriteNum(3);
 mWriteNum(4);
 mWriteNum(5);
 mWriteNum(6);
 mWrite(this->width);
 mWrite(this->height);
 mWriteNum(9);
 mWriteNum(10);
 mWriteNum(11);

 int pixelSize=size-54;
 mWrite(pixelSize);

 mWrite(this->xpelsPerMeter);
 mWrite(this->ypelsPerMeter);
 mWriteNum(15);
 mWriteNum(16);

 fwrite((void*)rgbArray,sizeof(uint8),pixelSize,bmpfile);

 fclose(bmpfile);
 return ;
}
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