static Edge GoHorizontal(int row, int column, Gradients gradients, Arr edgeMap, Edges edges, int rows, int columns, int minLength)
{
var left = GoLeft(row, column);
var right = GoRight(row, column);
if (left.Count >= minLength)
{
if (right.Count >= minLength)
{
left.AddLastFrom(right);
}
return(left);
}
else if (right.Count >= minLength)
{
return(right);
}
else
{
return(new Edge());
}
Edge GoLeft(int r, int c)
{
var edge = new Edge();
double upGradient, straightGradient, downGradient, direction, edgel;
do
{
edgeMap.SetReal(r, c, 255);
edge.AddLast(new Point(c, r));
--c; // left
if (c == 0)
{
return(edge);
}
upGradient = gradients.GradientMap.GetReal(r - 1, c);
straightGradient = gradients.GradientMap.GetReal(r, c);
downGradient = gradients.GradientMap.GetReal(r + 1, c);
if (upGradient > straightGradient && upGradient > downGradient)
{
--r; // up
if (r == 0)
{
return(edge);
}
}
else if (downGradient > straightGradient && downGradient > upGradient)
{
++r; // down
if (r == r - 1)
{
return(edge);
}
}
else if (straightGradient == 0)
{
return(edge);
}
edgel = edgeMap.GetReal(r, c);
if (edgel != 0)
{
return(edge);
}
direction = gradients.DirectionMap.GetReal(r, c);
}while(direction == Gradients.HorizontalValue);
// go vertical
var vertical = GoVertical(r, c, gradients, edgeMap, edges, rows, columns, minLength);
if (!vertical.IsEmpty)
{
var verticalHead = vertical.First.Value;
if (verticalHead.X == c && verticalHead.Y == r)
{
edge.AddLastFrom(vertical);
}
else
{
var verticalTail = vertical.Last.Value;
if (verticalTail.X == c && verticalTail.Y == r)
{
edge.AddLastFrom(vertical, true);
}
else
{
edges.Add(vertical);
}
}
}
if (edge.Count >= minLength)
{
return(edge);
}
return(new Edge());
}
Edge GoRight(int r, int c)
{
var edge = new Edge();
double upGradient, straightGradient, downGradient, direction, edgel;
do
{
edgeMap.SetReal(r, c, 255);
++c; // right
if (c == columns - 1)
{
return(edge);
}
upGradient = gradients.GradientMap.GetReal(r - 1, c);
straightGradient = gradients.GradientMap.GetReal(r, c);
downGradient = gradients.GradientMap.GetReal(r + 1, c);
if (upGradient > straightGradient && upGradient > downGradient)
{
--r; // up
if (r == 0)
{
return(edge);
}
}
else if (downGradient > straightGradient && downGradient > upGradient)
{
++r; // down
if (r == rows - 1)
{
return(edge);
}
}
else if (straightGradient == 0)
{
return(edge);
}
edgel = edgeMap.GetReal(r, c);
if (edgel != 0)
{
return(edge);
}
direction = gradients.DirectionMap.GetReal(r, c);
}while(direction == Gradients.HorizontalValue);
// go vertical
var vertical = GoVertical(r, c, gradients, edgeMap, edges, rows, columns, minLength);
if (!vertical.IsEmpty)
{
var verticalHead = vertical.First.Value;
if (verticalHead.X == c && verticalHead.Y == r)
{
edge.AddLastFrom(vertical);
}
else
{
var verticalTail = vertical.Last.Value;
if (verticalTail.X == c && verticalTail.Y == r)
{
edge.AddLastFrom(vertical, true);
}
else
{
edges.Add(vertical);
}
}
}
if (edge.Count >= minLength)
{
return(edge);
}
return(new Edge());
}
}