任意角度图片旋转

void S_PicXZ(Graphics::TBitmap *Source,Graphics::TBitmap *NewPic,int angle)//

{

if(angle>180)angle=360-angle;

if(angle<-180)angle=360+angle;

float radians=(2*3.1416*angle)/360;

float cosine=(float)cos(radians);

float sine=(float)sin(radians);

float Point1x=(-Source->Height*sine);

float Point1y=(Source->Height*cosine);

float Point2x=(Source->Width*cosine-Source->Height*sine);

float Point2y=(Source->Height*cosine+Source->Width*sine);

float Point3x=(Source->Width*cosine);

float Point3y=(Source->Width*sine);

float minx=min((float)0,min(Point1x,min(Point2x,Point3x)));

float miny=min((float)0,min(Point1y,min(Point2y,Point3y)));

float maxx=max(Point1x,max(Point2x,Point3x));

float maxy=max(Point1y,max(Point2y,Point3y));

int DestBitmapWidth,DestBitmapHeight;

if(angle>90&&angle<180)

DestBitmapWidth=(int)ceil(-minx);

else

DestBitmapWidth=(int)ceil(maxx-minx);

if(angle>-180&&angle<-90)

DestBitmapHeight=(int)ceil(-miny);

else

DestBitmapHeight=(int)ceil(maxy-miny);

NewPic->Height=DestBitmapHeight;

NewPic->Width=DestBitmapWidth;

for(int x=0;x<DestBitmapWidth;x++)

{

for(int y=0;y<DestBitmapHeight;y++)

{

int SrcBitmapx=(int)((x+minx)*cosine+(y+miny)*sine);

int SrcBitmapy=(int)((y+miny)*cosine-(x+minx)*sine);

if(SrcBitmapx>=0&&SrcBitmapx<Source->Width&&SrcBitmapy>=0&&

SrcBitmapy<Source->Height)

{

NewPic->Canvas->Pixels[x][y]=Source->Canvas->Pixels[SrcBitmapx][SrcBitmapy];

}

}

}

}