Path2D GeometricRecognizer::resample(Path2D points)
{
double interval = pathLength(points) / (numPointsInGesture - 1); // interval length
double D = 0.0;
Path2D newPoints;
//--- Store first point since we'll never resample it out of existence
newPoints.push_back(points.front());
for(int i = 1; i < (int)points.size(); i++)
{
Point2D currentPoint = points[i];
Point2D previousPoint = points[i-1];
double d = getDistance(previousPoint, currentPoint);
if ((D + d) >= interval)
{
double qx = previousPoint.x + ((interval - D) / d) * (currentPoint.x - previousPoint.x);
double qy = previousPoint.y + ((interval - D) / d) * (currentPoint.y - previousPoint.y);
Point2D point(qx, qy);
newPoints.push_back(point);
points.insert(points.begin() + i, point);
D = 0.0;
}
else D += d;
}
// somtimes we fall a rounding-error short of adding the last point, so add it if so
if (newPoints.size() == (numPointsInGesture - 1))
{
newPoints.push_back(points.back());
}
return newPoints;
}
/**
* Shift the points so that the center is at 0,0.
* That way, if everyone centers at the same place, we can measure
* the distance between each pair of points without worrying about
* where each point was originally drawn
* If we didn't do this, shapes drawn at the top of the screen
* would have a hard time matching shapes drawn at the bottom
* of the screen
*/
Path2D GeometricRecognizer::translateToOrigin(Path2D points)
{
Point2D c = centroid(points);
Path2D newPoints;
for (Path2DIterator i = points.begin(); i != points.end(); i++)
{
Point2D point = *i;
double qx = point.x - c.x;
double qy = point.y - c.y;
newPoints.push_back(Point2D(qx, qy));
}
return newPoints;
}
Path2D GeometricRecognizer::rotateBy(Path2D points, double rotation)
{
Point2D c = centroid(points);
//--- can't name cos; creates compiler error since VC++ can't
//--- tell the difference between the variable and function
double cosine = cos(rotation);
double sine = sin(rotation);
Path2D newPoints;
for (Path2DIterator i = points.begin(); i != points.end(); i++)
{
Point2D point = *i;
double qx = (point.x - c.x) * cosine - (point.y - c.y) * sine + c.x;
double qy = (point.x - c.x) * sine + (point.y - c.y) * cosine + c.y;
newPoints.push_back(Point2D(qx, qy));
}
return newPoints;
}
Path2D GeometricRecognizer::scaleToSquare(Path2D points)
{
//--- Figure out the smallest box that can contain the path
DollarRecognizer::Rectangle box = boundingBox(points);
Path2D newPoints;
for (Path2DIterator i = points.begin(); i != points.end(); i++)
{
Point2D point = *i;
//--- Scale the points to fit the main box
//--- So if we wanted everything 100x100 and this was 50x50,
//--- we'd multiply every point by 2
double scaledX = point.x * (this->squareSize / box.width);
double scaledY = point.y * (this->squareSize / box.height);
//--- Why are we adding them to a new list rather than
//--- just scaling them in-place?
// TODO: try scaling in place (once you know this way works)
newPoints.push_back(Point2D(scaledX, scaledY));
}
return newPoints;
}
