kev/Drawer/Module/GeoSigmaDraw/SplineAlgorithm.cpp

#include "StdAfx.h"
#include "SplineAlgorithm.h"
#include <cfloat>

int SplineAlgorithm::FindClosestPointIndex(const dfPoint& point, const CCurveEx* pCurve)
{
	if (pCurve == nullptr)
		return -1;
	int closestIndex = -1;
	double minDistSq = DBL_MAX;
	for (int j = 0; j < pCurve->num; ++j)
	{
		double dx = point.x0 - pCurve->x[j];
		double dy = point.y0 - pCurve->y[j];
		double distSq = dx * dx + dy * dy;
		if (distSq < minDistSq)
		{
			minDistSq = distSq;
			closestIndex = j;
		}
	}
	return closestIndex;
}

std::vector<int> SplineAlgorithm::FindClosestPointIndices(const std::vector<dfPoint>& points, const CCurveEx* pCurve)
{
	std::vector<int> indices;
	if (pCurve == nullptr)
		return indices;
	indices.reserve(points.size());
	for (const auto& pt : points)
		indices.push_back(FindClosestPointIndex(pt, pCurve));
	return indices;
}

void SplineAlgorithm::SimplifyCurve(CCurveEx& input, double errorThreshold, int oldHandleCount, CCurveEx& output)
{
	CCurveRedundant redundant;
	redundant.SetCurve(input);
	double baseErr = errorThreshold;
	bool isFirstGeneration = (oldHandleCount == 0);

	if (isFirstGeneration)
	{
		redundant.Execute(baseErr);
		redundant.GetRedundantCurve(output);
	}
	else
	{
		redundant.Execute(baseErr);
		CCurveEx tempCurve;
		redundant.GetRedundantCurve(tempCurve);
		const double maxGrowthRatio = 1.2;
		bool isTooManyHandles = (tempCurve.num > oldHandleCount * maxGrowthRatio);

		if (isTooManyHandles)
		{
			double actualGrowthRatio = (double)tempCurve.num / oldHandleCount;
			double adjustedErr = baseErr * actualGrowthRatio;
			redundant.Execute(adjustedErr);
			redundant.GetRedundantCurve(output);
		}
		else
		{
			output = tempCurve;
		}
	}
}