C++Builder图片旋转问题

TPaintBox *Image2 = new TPaintBox(this);

		Image2->Parent=this;

		Image2->Enabled=false;

		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=(-Image1->Height*sine);

		float Point1y=(Image1->Height*cosine);

		float Point2x=(Image1->Width*cosine-Image1->Height*sine);

		float Point2y=(Image1->Height*cosine+Image1->Width*sine);

		float Point3x=(Image1->Width*cosine);

		float Point3y=(Image1->Width*sine);

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

		float miny=min(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);

		Image2->Height=DestBitmapHeight;

		Image2->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<Image1->Width&&SrcBitmapy>=0&&

				SrcBitmapy<Image1->Height)

					{

					Image2->Canvas->Pixels[x][y]=PaintBox1->Canvas->Pixels[SrcBitmapx][SrcBitmapy];

					}

				}

			}

			BitBlt(PaintBox1->Canvas->Handle, 0, 0, PaintBox1->ClientWidth, PaintBox1->ClientHeight, Image2->Canvas->Handle, 0, 0, SRCCOPY);

			delete Image2;