/// <summary>
/// Horizontal and vertical scans overlap
/// </summary>
internal bool Overlap(Finder other)
{
return(other._col1 < _col2 && other._col2 >= _col1 && other.Row1 < Row2 && other.Row2 >= Row1);
}
/////////////////////////////////////////////////////////////////////
// Test QR corner for validity
/////////////////////////////////////////////////////////////////////
internal static Corner CreateCorner
(
Finder topLeftFinder,
Finder topRightFinder,
Finder bottomLeftFinder
)
{
// try all three possible permutation of three finders
for (int index = 0; index < 3; index++)
{
// TestCorner runs three times to test all posibilities
// rotate top left, top right and bottom left
if (index != 0)
{
Finder temp = topLeftFinder;
topLeftFinder = topRightFinder;
topRightFinder = bottomLeftFinder;
bottomLeftFinder = temp;
}
// top line slope
double topLineDeltaX = topRightFinder.Col - topLeftFinder.Col;
double topLineDeltaY = topRightFinder._row - topLeftFinder._row;
// left line slope
double leftLineDeltaX = bottomLeftFinder.Col - topLeftFinder.Col;
double leftLineDeltaY = bottomLeftFinder._row - topLeftFinder._row;
// top line length
double topLineLength = Math.Sqrt(topLineDeltaX * topLineDeltaX + topLineDeltaY * topLineDeltaY);
// left line length
double leftLineLength = Math.Sqrt(leftLineDeltaX * leftLineDeltaX + leftLineDeltaY * leftLineDeltaY);
// the short side must be at least 80% of the long side
if (Math.Min(topLineLength, leftLineLength) < QRDecoder.CORNER_SIDE_LENGTH_DEV * Math.Max(topLineLength, leftLineLength))
{
continue;
}
// top line vector
double topLineSin = topLineDeltaY / topLineLength;
double topLineCos = topLineDeltaX / topLineLength;
// rotate lines such that top line is parallel to x axis
// left line after rotation
double newLeftX = topLineCos * leftLineDeltaX + topLineSin * leftLineDeltaY;
double newLeftY = -topLineSin * leftLineDeltaX + topLineCos * leftLineDeltaY;
// new left line X should be zero (or between +/- 4 deg)
if (Math.Abs(newLeftX / leftLineLength) > QRDecoder.CORNER_RIGHT_ANGLE_DEV)
{
continue;
}
// swap top line with left line
if (newLeftY < 0)
{
// swap top left with bottom right
Finder tempFinder = topRightFinder;
topRightFinder = bottomLeftFinder;
bottomLeftFinder = tempFinder;
}
return(new Corner(topLeftFinder, topRightFinder, bottomLeftFinder));
}
return(null);
}