float StrokeCost(int strokeIndex, out StrokeMatch bestMatch)
{
StrokeTemplate template = Template[strokeIndex];
List <StrokeMatch> candidateMatches = InputMatches[strokeIndex];
float bestCost = float.PositiveInfinity;
bestMatch = null;
foreach (StrokeMatch match in candidateMatches)
{
if (match.Parts.Count != template.Parts.Count)
{
continue;
}
float cost = 0;
for (int partIndex = 0; partIndex < match.Parts.Count; partIndex++)
{
StrokePartMatch partMatch = match.Parts[partIndex];
StrokePartTemplate partTemplate = template.Parts[partIndex];
cost += partTemplate.MatchCost(partMatch);
}
cost += match.Cost * 30;
if (cost < bestCost)
{
bestCost = cost;
bestMatch = match;
}
}
return(bestCost);
}
StrokePartMatch MatchLine(int start, int end)
{
StrokePart line = new StrokePart(Input[start], Input[end]);
float multi = line.Length * 0.5f;
float a = 0, b = 0, c = 0; //Parabel coefficients
for (int i = start; i <= end; i++)
{
Vector2f point = Input[i];
float weight = Weight[i];
float scaledX = line.GetParallelPositionScaled(point);
float unscaledY = line.GetOrthoPositionUnscaled(point);
float unscaledOutside = (Math.Abs(scaledX) - 1) * multi;
if (unscaledOutside > 0)
{
c += weight * (unscaledOutside * unscaledOutside + unscaledY * unscaledY);
}
else
{
float param = (1 - scaledX * scaledX) * multi;
a += weight * param * param;
b += weight * (-2) * param * unscaledY;
c += weight * unscaledY * unscaledY;
}
}
float optimalCurve = -b / (2 * a);
var result = new StrokePartMatch(line.StartPoint, line.EndPoint, optimalCurve);
result.DeltaCurveCost = a;
result.MinCost = c - b * b / (4 * a);
return(result);
}
public float MatchCost(StrokePartMatch match)
{
float lenDelta = match.Delta.Length - Length;
float lenDeltaSquared = lenDelta * lenDelta;
float angleDelta = (match.Delta.AngleTo() - Angle) / (2 * (float)Math.PI);
angleDelta = 2 * (angleDelta - (float)Math.Floor(angleDelta + 0.5f));
float angleDeltaSquared = angleDelta * angleDelta;
float curveDelta = match.Curve - Curve;
float curveDeltaSquared = curveDelta * curveDelta;
float startDeltaSquared = (match.StartPoint - StartPoint).LengthSquared;
float endDeltaSquared = (match.StartPoint - StartPoint).LengthSquared;
float cost = 3*lenDeltaSquared +
4*(startDeltaSquared + endDeltaSquared)
+6* curveDeltaSquared + 20*Length*angleDeltaSquared;
return cost;
}
public float MatchCost(StrokePartMatch match)
{
float lenDelta = match.Delta.Length - Length;
float lenDeltaSquared = lenDelta * lenDelta;
float angleDelta = (match.Delta.AngleTo() - Angle) / (2 * (float)Math.PI);
angleDelta = 2 * (angleDelta - (float)Math.Floor(angleDelta + 0.5f));
float angleDeltaSquared = angleDelta * angleDelta;
float curveDelta = match.Curve - Curve;
float curveDeltaSquared = curveDelta * curveDelta;
float startDeltaSquared = (match.StartPoint - StartPoint).LengthSquared;
float endDeltaSquared = (match.StartPoint - StartPoint).LengthSquared;
float cost = 3 * lenDeltaSquared +
4 * (startDeltaSquared + endDeltaSquared)
+ 6 * curveDeltaSquared + 20 * Length * angleDeltaSquared;
return(cost);
}
private IEnumerable <StrokeMatch> Match()
{
if (Input.Count < 2)
{
yield break;
}
var singleMatch = new List <StrokePartMatch>();
singleMatch.Add(MatchLine(0, Input.Count - 1));
yield return(new StrokeMatch(singleMatch));
foreach (int i in InterestingPoints)
{
StrokePartMatch match1 = MatchLine(0, i);
StrokePartMatch match2 = MatchLine(i, Input.Count - 1);
var match = new List <StrokePartMatch>();
match.Add(match1);
match.Add(match2);
StrokeMatch fullMatch = new StrokeMatch(match);
yield return(fullMatch);
}
foreach (int i in InterestingPoints)
{
foreach (int j in InterestingPoints)
{
if (i >= j)
{
continue;
}
StrokePartMatch match1 = MatchLine(0, i);
StrokePartMatch match2 = MatchLine(i, j);
StrokePartMatch match3 = MatchLine(j, Input.Count - 1);
var match = new List <StrokePartMatch>();
match.Add(match1);
match.Add(match2);
match.Add(match3);
StrokeMatch fullMatch = new StrokeMatch(match);
yield return(fullMatch);
}
}
}
StrokePartMatch MatchLine(int start, int end)
{
StrokePart line = new StrokePart(Input[start], Input[end]);
float multi = line.Length* 0.5f;
float a = 0, b = 0, c = 0;//Parabel coefficients
for (int i = start; i <= end; i++)
{
Vector2f point = Input[i];
float weight = Weight[i];
float scaledX = line.GetParallelPositionScaled(point);
float unscaledY = line.GetOrthoPositionUnscaled(point);
float unscaledOutside = (Math.Abs(scaledX) - 1) * multi;
if (unscaledOutside > 0)
{
c += weight * (unscaledOutside * unscaledOutside + unscaledY *unscaledY );
}
else
{
float param = (1 - scaledX * scaledX) * multi;
a += weight * param * param;
b += weight * (-2) * param * unscaledY;
c += weight * unscaledY * unscaledY;
}
}
float optimalCurve = -b / (2 * a);
var result = new StrokePartMatch(line.StartPoint, line.EndPoint, optimalCurve);
result.DeltaCurveCost = a;
result.MinCost = c - b * b / (4 * a);
return result;
}