C語言實現(xiàn)bmp圖像幾何變換（移動，旋轉(zhuǎn)，鏡像，轉(zhuǎn)置，縮放）

• 移動
• 旋轉(zhuǎn)
• 鏡像
• 轉(zhuǎn)置
• 縮放

自定義結(jié)構(gòu)及函數(shù)如下：

#define pi 3.1415926
typedef struct {unsigned char bfType[2];unsigned long bfSize;unsigned short bfReserved1;unsigned short bfReserved2;unsigned long bfOffBits;
}bitmapFileHeader;typedef struct {unsigned long biSize;unsigned long biWidth;unsigned long biHeight;unsigned short biPlanes;unsigned short biBitCount;unsigned long biCompression;unsigned long biSizeImage;long biXPixPerMeter;long biYPixPerMeter;unsigned long biClrUsed;unsigned long biClrImportant;
}bitmapInfoHeader;/*
typedef struct{unsigned char rgbBlue;unsigned char rgbGreen;unsigned char rgbRed;unsigned rgbReserved;
}rgbQUAD;
*/
//這里沒有考慮有調(diào)色板的位圖
//如果是保存有調(diào)色板的位圖的話，需要更改這個結(jié)構(gòu)體
typedef struct{bitmapFileHeader bfHeader;bitmapInfoHeader biHeader;unsigned char *imgData;
}bmp;double fmax(double a,double b){if(a>b)return a;else return b;
}

涉及bmp圖像讀取和保存代碼：

    //bmp圖像讀取bmp b;b.imgData=(unsigned char*)malloc(sizeof(unsigned char)*imSize);memset(b.imgData,0,sizeof(unsigned char)*imSize);memcpy(&(b.bfHeader),&bfHeader,sizeof(bfHeader));memcpy(&(b.biHeader),&biHeader,sizeof(biHeader));//bmp圖像保存char savePath[]="D:\Temp\\save_test.bmp";FILE *f=fopen(savePath,"wb");if(f==NULL){perror("can not open file!");return -2;}fwrite(&b.bfHeader,sizeof(bitmapFileHeader),1,f);fwrite(&b.biHeader,sizeof(bitmapInfoHeader),1,f);fwrite(b.imgData,sizeof(unsigned char)*b.biHeader.biSizeImage,1,f);fclose(f);

使用的圖像：

移動

int xOffset=100,yOffset=100;if(width<xOffset||height<yOffset)return -1;for(int i=0;i<height;i++){for(int j=0;j<width*3;j++){if(i+yOffset<height&&i+yOffset>=0&&j+xOffset*3<width*3&&j+xOffset*3>=0)b.imgData[lineBytes*(i+yOffset)+j+xOffset*3]=imageData[lineBytes*i+j];}}

旋轉(zhuǎn)

	//對圖像進行旋轉(zhuǎn)double angle=pi/3;double half_w=width/2.0,half_h=height/2.0;double cosa=cos(angle),sina=sin(angle);double x1=-half_w*cosa+ half_h*sina,y1=half_w*sina+half_h*cosa;double x2=half_w*cosa+half_h*sina,y2=-half_w*sina+half_h*cosa;double x3=-half_w*cosa-half_h*sina,y3=half_w*sina-half_h*cosa;double x4=half_w*cosa-half_h*sina,y4=-half_w*sina-half_h*cosa;int width_new=(int)(fmax(fabs(x4-x1),fabs(x3-x2))+0.5);int height_new=(int)(fmax(fabs(y4-y1),fabs(y3-y2))+0.5);int lineBytes_new=(width_new*bitCount+31)/32*4;b.biHeader.biWidth=width_new;b.biHeader.biHeight=height_new;b.biHeader.biSizeImage=lineBytes_new*height_new;b.bfHeader.bfSize=54+lineBytes_new*height_new;b.imgData=(unsigned char*)realloc(b.imgData,lineBytes_new*height_new*sizeof(unsigned char));memset(b.imgData,0,lineBytes_new*height_new*sizeof(unsigned char));double const1=-width_new*cosa/2.0+height_new*sina/2.0+width/2.0;double const2=-width_new*sina/2.0-height_new*cosa/2.0+height/2.0;int x0,y0;for(int i=0;i<height_new;i++){for(int j=0;j<width_new;j++){x0=(int)(j*cosa-i*sina+const1+0.5);y0=(int)(j*sina+i*cosa+const2+0.5);if(x0>=0&&x0<width&&y0>=0&&y0<height){b.imgData[lineBytes_new*i+j*3]=imageData[lineBytes*y0+x0*3];b.imgData[lineBytes_new*i+j*3+1]=imageData[lineBytes*y0+x0*3+1];b.imgData[lineBytes_new*i+j*3+2]=imageData[lineBytes*y0+x0*3+2];}}}

鏡像

//鏡像for(int i=0;i<height;i++){for(int j=0;j<width*3;j++){b.imgData[lineBytes*i+j]=imageData[lineBytes*(height-1-i)+j];}}

轉(zhuǎn)置

	int lineBytes_new=(height*bitCount+31)/32*4;b.biHeader.biWidth=height;b.biHeader.biHeight=width;b.biHeader.biSizeImage=width*lineBytes_new*sizeof(unsigned char);b.bfHeader.bfSize=54+width*lineBytes_new*sizeof(unsigned char);b.imgData=(unsigned char*)realloc(b.imgData,lineBytes_new*width*sizeof(unsigned char));memset(b.imgData,0,width*lineBytes_new*sizeof(unsigned char));for(int i=0;i<height;i++){for(int j=0;j<width;j++){b.imgData[lineBytes_new*(width-1-j)+(height-1-i)*3]=imageData[lineBytes*i+j*3];b.imgData[lineBytes_new*(width-1-j)+(height-1-i)*3+1]=imageData[lineBytes*i+j*3+1];b.imgData[lineBytes_new*(width-1-j)+(height-1-i)*3+2]=imageData[lineBytes*i+j*3+2];}}

縮放

//縮放double ratio=2.0;int width_new=(int)(width*ratio+0.5),height_new=(int)(height*ratio+0.5);int lineBytes_new=(width_new*bitCount+31)/32*4;b.biHeader.biWidth=width_new;b.biHeader.biHeight=height_new;b.biHeader.biSizeImage=height_new*lineBytes_new*sizeof(unsigned char);b.bfHeader.bfSize=54+height_new*lineBytes_new*sizeof(unsigned char);b.imgData=(unsigned char*)realloc(b.imgData,height_new*lineBytes_new*sizeof(unsigned char));memset(b.imgData,0,height_new*lineBytes_new*sizeof(unsigned char));int x0,y0;for(int i=0;i<height_new;i++){for(int j=0;j<width_new;j++){x0=(int)(j/ratio);y0=(int)(i/ratio);if(x0>=0&&x0<width&&y0>=0&&y0<height){b.imgData[lineBytes_new*i+j*3]=imageData[lineBytes*y0+x0*3];b.imgData[lineBytes_new*i+j*3+1]=imageData[lineBytes*y0+x0*3+1];b.imgData[lineBytes_new*i+j*3+2]=imageData[lineBytes*y0+x0*3+2];}}}

總結(jié)

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