C++之图片旋转90，再保存

下面测试代码只需要全部放在一个.cpp文件里就行

//#include "stdafx.h"
#include <stdio.h>
#include <string>
#include <math.h>
#include <windows.h>
using namespace std;

#define PI 3.1415926535
//角度到弧度转化
#define RADIAN(angle) ((angle)*PI/180.0)

void Rotation(const string& srcFile,const string& desFile,int angle)
{
BITMAPFILEHEADER bmfHeader;
BITMAPINFOHEADER bmiHeader;

FILE *pFile;
if ((pFile = fopen(srcFile.c_str(),"rb")) == NULL)
{
printf("open bmp file error.");
exit(-1);
}
//读取文件和Bitmap头信息
fseek(pFile,0,SEEK_SET);
fread(&bmfHeader,sizeof(BITMAPFILEHEADER),1,pFile);
fread(&bmiHeader,sizeof(BITMAPINFOHEADER),1,pFile);
//先不支持小于16位的位图
int bitCount = bmiHeader.biBitCount;
if (bitCount < 16)
{
exit(-1);
}
int srcW = bmiHeader.biWidth;
int srcH = bmiHeader.biHeight;
//原图像每一行去除偏移量的字节数
int lineSize = bitCount * srcW / 8;
//偏移量，windows系统要求每个扫描行按四字节对齐
int alignBytes = ((bmiHeader.biWidth * bitCount + 31) & ~31) / 8L
- bmiHeader.biWidth * bitCount / 8L;
//原图像缓存
int srcBufSize = lineSize * srcH;
BYTE* srcBuf = new BYTE[srcBufSize];
int i,j;
//读取文件中数据
for (i = 0; i < srcH; i++)
{
fread(&srcBuf[lineSize * i],lineSize,1,pFile);
fseek(pFile,alignBytes,SEEK_CUR);
}
//以图像中心为原点左上角，右上角，左下角和右下角的坐标,用于计算旋转后的图像的宽和高
POINT pLT,pRT,pLB,pRB;
pLT.x = -srcW/2;pLT.y = srcH/2;
pRT.x = srcW/2;pRT.y = srcH/2;
pLB.x = -srcW/2;pLB.y = -srcH/2;
pRB.x = srcW/2; pRB.y = -srcH/2;
//旋转之后的坐标
POINT pLTN,pRTN,pLBN,pRBN;
double sina = sin(RADIAN(angle));
double cosa = cos(RADIAN(angle));
pLTN.x = pLT.x*cosa + pLT.y*sina;
pLTN.y = -pLT.x*sina + pLT.y*cosa;
pRTN.x = pRT.x*cosa + pRT.y*sina;
pRTN.y = -pRT.x*sina + pRT.y*cosa;
pLBN.x = pLB.x*cosa + pLB.y*sina;
pLBN.y = -pLB.x*sina + pLB.y*cosa;
pRBN.x = pRB.x*cosa + pRB.y*sina;
pRBN.y = -pRB.x*sina + pRB.y*cosa;
//旋转后图像宽和高
int desWidth = max(abs(pRBN.x - pLTN.x),abs(pRTN.x - pLBN.x));
int desHeight = max(abs(pRBN.y - pLTN.y),abs(pRTN.y - pLBN.y));
//分配旋转后图像的缓存
int desBufSize = ((desWidth * bitCount + 31) / 32) * 4 * desHeight;
BYTE *desBuf = new BYTE[desBufSize];
//将所有像素都预置为白色
memset(desBuf,255,desBufSize);
//新图像每一行字节数，带有偏移量
int desLineSize = ((desWidth * bitCount + 31) / 32) * 4;
//通过新图像的坐标，计算对应的原图像的坐标
for (i = 0; i < desHeight; i++)
{
for (j = 0; j < desWidth; j++)
{
//转换到以图像为中心的坐标系，并进行逆旋转
int tX = (j - desWidth / 2)*cos(RADIAN(360 - angle)) + (-i + desHeight / 2)*sin(RADIAN(360 - angle));
int tY = -(j - desWidth / 2)*sin(RADIAN(360 - angle)) + (-i + desHeight / 2)*cos(RADIAN(360 - angle));
//如果这个坐标不在原图像内，则不赋值
if (tX > srcW / 2 || tX < -srcW / 2 || tY > srcH / 2 || tY < -srcH / 2)
{
continue;
}
//再转换到原坐标系下
int tXN = tX + srcW / 2; int tYN = abs(tY - srcH / 2);
//值拷贝
memcpy(&desBuf[i * desLineSize + j * bitCount / 8],&srcBuf[tYN * lineSize + tXN * bitCount / 8],3);
}
}

//创建目标文件
HFILE hfile = _lcreat(desFile.c_str(),0);
//文件头信息
BITMAPFILEHEADER nbmfHeader;
nbmfHeader.bfType = 0x4D42;
nbmfHeader.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER)
+ desWidth * desHeight * bitCount / 8;
nbmfHeader.bfReserved1 = 0;
nbmfHeader.bfReserved2 = 0;
nbmfHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
//Bitmap头信息
BITMAPINFOHEADER bmi;
bmi.biSize=sizeof(BITMAPINFOHEADER);
bmi.biWidth=desWidth;
bmi.biHeight=desHeight;
bmi.biPlanes=1;
bmi.biBitCount=bitCount;
bmi.biCompression=BI_RGB;
bmi.biSizeImage=0;
bmi.biXPelsPerMeter=0;
bmi.biYPelsPerMeter=0;
bmi.biClrUsed=0;
bmi.biClrImportant=0;

//写入文件头信息
_lwrite(hfile,(LPCSTR)&nbmfHeader,sizeof(BITMAPFILEHEADER));
//写入Bitmap头信息
_lwrite(hfile,(LPCSTR)&bmi,sizeof(BITMAPINFOHEADER));
//写入图像数据
_lwrite(hfile,(LPCSTR)desBuf,desBufSize);
_lclose(hfile);
}

int main(int argc, char* argv[])
{
FILE *pFile;
if ((pFile = fopen("D:\ZZCprot\测试打印工具\TestPrinter\output\456test.bmp","rb")) == NULL)
{
printf("open bmp file error.");
return -1;
}
string srcFile("D:\ZZCprot\测试打印工具\TestPrinter\output\456test.bmp");
string desFile("D:\ZZCprot\测试打印工具\TestPrinter\output\Rotation.bmp");
Rotation(srcFile,desFile,90);
system("pause");
return 0;
}