C++ VPoint::Normalize方法代码示例

void VRadialGradientPattern::_ComputeFactors()
{
	//ensure that focal point lies inside exterior radius
	//(otherwise gradient drawing is undeterminate)
	if (fEndRadiusX != 0 && fEndRadiusY != 0 && (fStartPoint.x != fEndPoint.x || fStartPoint.y != fEndPoint.y))
	{
		//map focal to circle coordinate space with center at end point and radius equal to fEndRadiusX
		GReal fx = fStartPoint.x-fEndPoint.x;
		GReal fy = (fStartPoint.y-fEndPoint.y)*fEndRadiusX/fEndRadiusY;
		
		if ((fx*fx+fy*fy) > fEndRadiusX*fEndRadiusX*(GReal) 0.9999*(GReal) 0.9999) //radius*0.9999 in order to avoid math discrepancy errors
		{
			//set focal to intersection with circle
			GReal angle = atan2(fy,fx);
			fy = sin(angle)*fEndRadiusX*(GReal) 0.9999;
			fx = cos(angle)*fEndRadiusX*(GReal) 0.9999;
			
			//map focal from circle coordinate space to user coordinate space 
			fStartPoint.x = fx+fEndPoint.x;
			fStartPoint.y = fy*fEndRadiusY/fEndRadiusX+fEndPoint.y;
		}
	}
	
	//here end point and radius need to be adjusted for reflect and repeat wrapping modes
	if (GetWrapMode() != ePatternWrapClamp)
	{	
		VPoint startPoint	= fStartPoint;
		VPoint endPoint		= fEndPoint;	
	
		//map radius and focal coordinates from ellipsoid coordinate space (user space) to circular coordinate space centered on end point
		//(more easy to work with circular coordinate space)
		GReal endRadius = xbox::Max( fEndRadiusX, fEndRadiusY);
	
		if (startPoint != endPoint
			&&
			fEndRadiusX != fEndRadiusY
			&&
			fEndRadiusX != 0
			&& 
			fEndRadiusY != 0)
		{
			VPoint focal = startPoint-endPoint;
			if (fEndRadiusX >= fEndRadiusY)
				focal.y *= fEndRadiusX/fEndRadiusY;
			else
				focal.x *= fEndRadiusY/fEndRadiusX;
		
			startPoint = endPoint + focal;
		}
	
		//if focal is not centered and as radius is enlarged for tiling wrapping modes, 
		//we must modify center point to ensure ratio (dist focal to radius)/radius keep the same
		//otherwise drawing will not be correct
		if (startPoint != endPoint && endRadius != 0)
		{
			VPoint vFocalToCenter = endPoint-startPoint;
			GReal distFocalToCenter = vFocalToCenter.GetLength();
			if (distFocalToCenter > endRadius)
				distFocalToCenter = endRadius;
			GReal distFocalToRadius = endRadius-distFocalToCenter;
			
			vFocalToCenter.Normalize();
			endRadius *= kPATTERN_GRADIENT_TILE_MAX_COUNT;
			endPoint += vFocalToCenter*(endRadius-distFocalToRadius*kPATTERN_GRADIENT_TILE_MAX_COUNT);
			
			//ensure that focal still lies in exterior circle :
			//because of math discrepancy errors (especially near end radius border) we need to check that to avoid Quartz2D artifacts
			
			//map focal to circle coordinate space with center at new end point
			GReal fx = startPoint.x-endPoint.x;
			GReal fy = startPoint.y-endPoint.y;
			
			while ((fx*fx+fy*fy) > endRadius*endRadius*(GReal) 0.9999*(GReal) 0.9999)	//radius*0.9999 to deal with math discrepancy errors (value 0.9999 determined by experimentation)
				endRadius *= (GReal) 1.01; 
		}
		else
			//focal is centered: only enlarge radius
			endRadius *= kPATTERN_GRADIENT_TILE_MAX_COUNT;
		
		//update tiling datas
		fEndRadiusTiling = endRadius;
		
		if (endPoint != fEndPoint)
		{
			//adjust new end point position (to take account ellipsoid shape)
			if (fEndRadiusX >= fEndRadiusY)
			{
				GReal ratio = fEndRadiusY/fEndRadiusX;
				
				startPoint -= endPoint;
				
				//map new end point from circular coordinate space centered on last end point to user space
				//(this will be new origin for circular coordinate space)
				endPoint -= fEndPoint;
				endPoint.y *= ratio;
				fEndPointTiling = fEndPoint+endPoint;
				
#if VERSIONMAC
				startPoint += fEndPointTiling;	//keep start point in circular coordinate space whom origin is equal to end point
												//(transform to user space is delayed to gradient transform)
//.........这里部分代码省略.........