/// <remarks>
/// Calculates the direction in radians between this point and the given point.
/// 0 is to the right, PI / 2 is up, etc.
///
/// @param comparePoint the point to get the direction to from this point
/// @return the direction in radians between this point and the given point.
/// </remarks>
public double GetDirection(WrittenPoint comparePoint)
{
double dx = X - comparePoint.X;
double dy = Y - comparePoint.Y;
return(Math.PI - Math.Atan2(dy, dx));
}
/// <remarks>
/// Calculates the direction in radians between this point and the given point.
/// 0 is to the right, PI / 2 is up, etc.
///
/// @param comparePoint the point to get the direction to from this point
/// @return the direction in radians between this point and the given point.
/// </remarks>
public double GetDirection(WrittenPoint comparePoint)
{
double dx = X - comparePoint.X;
double dy = Y - comparePoint.Y;
return Math.PI - Math.Atan2(dy, dx);
}
public double Distance(WrittenPoint comparePoint)
{
double dx = X - comparePoint.X;
double dy = Y - comparePoint.Y;
return(Math.Sqrt(dx * dx + dy * dy));
}
public List <SubStrokeDescriptor> GetSubStrokes(double charWidth, double charHeight)
{
if (!this.isAnalyzed)
{
this.AnalyzeAndMark();
}
List <SubStrokeDescriptor> subStrokes = new List <SubStrokeDescriptor>();
// Any WrittenStroke should have at least two points, (a single point cannot constitute a Stroke).
// We should therefore be safe calling an iterator without checking for the first point.
WrittenPoint previousPoint = pointList[0];
for (int i = 1; i != pointList.Count; ++i)
{
WrittenPoint nextPoint = pointList[i];
if (nextPoint.IsPivot)
{
// The direction from each previous point to each successive point, in radians.
double direction = previousPoint.GetDirection(nextPoint);
// Use the normalized length, to account for relative character size.
double normalizedLength = previousPoint.GetDistanceNormalized(nextPoint, charWidth, charHeight);
SubStrokeDescriptor subStroke = new SubStrokeDescriptor(direction, normalizedLength);
subStrokes.Add(subStroke);
previousPoint = nextPoint;
}
}
return(subStrokes);
}
public void AddPoint(WrittenPoint point,
ref double charLeftX, ref double charRightX,
ref double charTopY, ref double charBottomY)
{
int pointX = point.X;
int pointY = point.Y;
// Expand the bounding box coordinates for this WrittenCharacter in necessary.
charLeftX = Math.Min(pointX, charLeftX);
charRightX = Math.Max(pointX, charRightX);
charTopY = Math.Min(pointY, charTopY);
charBottomY = Math.Max(pointY, charBottomY);
this.pointList.Add(point);
}
public void AddPoint(WrittenPoint point,
ref double charLeftX, ref double charRightX,
ref double charTopY, ref double charBottomY)
{
int pointX = point.X;
int pointY = point.Y;
// Expand the bounding box coordinates for this WrittenCharacter in necessary.
charLeftX = Math.Min(pointX, charLeftX);
charRightX = Math.Max(pointX, charRightX);
charTopY = Math.Min(pointY, charTopY);
charBottomY = Math.Max(pointY, charBottomY);
this.pointList.Add(point);
}
/// <remarks>
/// Normalized length takes into account the size of the WrittenCharacter on the canvas.
/// For example, if the WrittenCharacter was written small in the upper left portion of the canvas,
/// then the lengths not be based on the full size of the canvas, but rather only on the relative
/// size of the WrittenCharacter.
///
/// @param comparePoint the point to get the normalized distance to from this point
///
/// @return the normalized length from this point to the compare point
/// </remarks>
public double GetDistanceNormalized(WrittenPoint comparePoint,
double charWidth, double charHeight)
{
double width = (double)charWidth;
double height = (double)charHeight;
// normalizer is a diagonal along a square with sides of size the larger dimension of the bounding box
double dimensionSquared = width > height ? width * width : height * height;
double normalizer = Math.Sqrt(dimensionSquared + dimensionSquared);
double distanceNormalized = Distance(comparePoint) / normalizer;
// shouldn't be longer than 1 if it's normalized
distanceNormalized = Math.Min(distanceNormalized, 1.0);
return(distanceNormalized);
}
/// <remarks>
/// Normalized length takes into account the size of the WrittenCharacter on the canvas.
/// For example, if the WrittenCharacter was written small in the upper left portion of the canvas,
/// then the lengths not be based on the full size of the canvas, but rather only on the relative
/// size of the WrittenCharacter.
///
/// @param comparePoint the point to get the normalized distance to from this point
///
/// @return the normalized length from this point to the compare point
/// </remarks>
public double GetDistanceNormalized(WrittenPoint comparePoint,
double charWidth, double charHeight)
{
double width = (double)charWidth;
double height = (double)charHeight;
// normalizer is a diagonal along a square with sides of size the larger dimension of the bounding box
double dimensionSquared = width > height ? width * width : height * height;
double normalizer = Math.Sqrt(dimensionSquared + dimensionSquared);
double distanceNormalized = Distance(comparePoint) / normalizer;
// shouldn't be longer than 1 if it's normalized
distanceNormalized = Math.Min(distanceNormalized, 1.0);
return distanceNormalized;
}
/// <summary>
/// Start recognizing a character in a BG thread after strokes have changed.
/// </summary>
private void startNewCharRecog(IEnumerable<WritingPad.Stroke> strokes)
{
// If there are other matchers running, stop them now
lock (runningMatchers)
{
foreach (StrokesMatcher sm in runningMatchers) sm.Stop();
}
// Convert stroke data to HanziLookup's format
WrittenCharacter wc = new WrittenCharacter();
foreach (WritingPad.Stroke stroke in strokes)
{
WrittenStroke ws = new WrittenStroke();
foreach (PointF p in stroke.Points)
{
WrittenPoint wp = new WrittenPoint((int)(p.X), (int)(p.Y));
ws.AddPoint(wp, ref wc.LeftX, ref wc.RightX, ref wc.TopY, ref wc.BottomY);
}
wc.AddStroke(ws);
}
if (wc.StrokeList.Count == 0)
{
// Don't bother doing anything if nothing has been input yet (number of strokes == 0).
ctrlCharPicker.SetItems(null);
return;
}
ThreadPool.QueueUserWorkItem(recognize, wc);
}
public double Distance(WrittenPoint comparePoint)
{
double dx = X - comparePoint.X;
double dy = Y - comparePoint.Y;
return Math.Sqrt(dx * dx + dy * dy);
}
/// <summary>
/// Analyzes the given WrittenStroke and marks its constituent WrittenPoints to demarcate the SubStrokes.
/// Points that demarcate between the SubStroke segments are marked as pivot points.
/// These pivot points can later be used to build up a List of SubStroke objects.
/// </summary>
public void AnalyzeAndMark()
{
var pointIter = pointList.GetEnumerator();
// It should be impossible for a stroke to have < 2 points, so we are safe calling next() twice.
pointIter.MoveNext();
WrittenPoint firstPoint = pointIter.Current;
WrittenPoint previousPoint = firstPoint;
pointIter.MoveNext();
WrittenPoint pivotPoint = pointIter.Current;
// The first point of a Stroke is always a pivot point.
firstPoint.IsPivot = true;
int subStrokeIndex = 1;
// The first point and the next point are always part of the first SubStroke.
firstPoint.SubStrokeIndex = subStrokeIndex;
pivotPoint.SubStrokeIndex = subStrokeIndex;
// localLength keeps track of the immediate distance between the latest three points.
// We can use the localLength to find an abrupt change in SubStrokes, such as at a corner.
// We do this by checking localLength against the distance between the first and last
// of the three points. If localLength is more than a certain amount longer than the
// length between the first and last point, then there must have been a corner of some kind.
double localLength = firstPoint.Distance(pivotPoint);
// runningLength keeps track of the length between the start of the current SubStroke
// and the point we are currently examining. If the runningLength becomes a certain
// amount longer than the straight distance between the first point and the current
// point, then there is a new SubStroke. This accounts for a more gradual change
// from one SubStroke segment to another, such as at a longish curve.
double runningLength = localLength;
// Iterate over the points, marking the appropriate ones as pivots.
while (pointIter.MoveNext())
{
WrittenPoint nextPoint = pointIter.Current;
// pivotPoint is the point we're currently examining to see if it's a pivot.
// We get the distance between this point and the next point and add it
// to the length sums we're using.
double pivotLength = pivotPoint.Distance(nextPoint);
localLength += pivotLength;
runningLength += pivotLength;
// Check the lengths against the ratios. If the lengths are a certain among
// longer than a straight line between the first and last point, then we
// mark the point as a pivot.
double distFromPrevious = previousPoint.Distance(nextPoint);
double distFromFirst = firstPoint.Distance(nextPoint);
if (localLength > MAX_LOCAL_LENGTH_RATIO * distFromPrevious ||
runningLength > MAX_RUNNING_LENGTH_RATIO * distFromFirst)
{
if (previousPoint.IsPivot && previousPoint.Distance(pivotPoint) < MIN_SEGMENT_LENGTH)
{
// If the previous point was a pivot and was very close to this point,
// which we are about to mark as a pivot, then unmark the previous point as a pivot.
// Also need to decrement the SubStroke that it belongs to since it's not part of
// the new SubStroke that begins at this pivot.
previousPoint.IsPivot = false;
previousPoint.SubStrokeIndex = subStrokeIndex - 1;
}
else
{
// If we didn't have to unmark a previous pivot, then the we can increment the SubStrokeIndex.
// If we did unmark a previous pivot, then the old count still applies and we don't need to increment.
subStrokeIndex++;
}
pivotPoint.IsPivot = true;
// A new SubStroke has begun, so the runningLength gets reset.
runningLength = pivotLength;
firstPoint = pivotPoint;
}
localLength = pivotLength; // Always update the localLength, since it deals with the last three seen points.
previousPoint = pivotPoint;
pivotPoint = nextPoint;
pivotPoint.SubStrokeIndex = subStrokeIndex;
}
// last point (currently referenced by pivotPoint) has to be a pivot
pivotPoint.IsPivot = true;
// Point before the final point may need to be handled specially.
// Often mouse action will produce an unintended small segment at the end.
// We'll want to unmark the previous point if it's also a pivot and very close to the lat point.
// However if the previous point is the first point of the stroke, then don't unmark it, because then we'd only have one pivot.
if (previousPoint.IsPivot &&
previousPoint.Distance(pivotPoint) < MIN_SEGMENT_LENGTH &&
previousPoint != this.pointList[0])
{
previousPoint.IsPivot = false;
pivotPoint.SubStrokeIndex = subStrokeIndex - 1;
}
// Mark the stroke as analyzed so that it won't need to be analyzed again.
this.isAnalyzed = true;
}
