public static IPositionSet getBlockLine(IPosition refPos, float itv0, IPosition startPos, IPosition endPos)
{
rX = refPos.GetX();
rY = refPos.GetY();
itv = itv0;
float sX = startPos.GetX();
float sY = startPos.GetY();
float eX = endPos.GetX();
float eY = endPos.GetY();
PositionSetEdit_ImplementByICollectionTemplate result = new PositionSetEdit_ImplementByICollectionTemplate();
//判断起点终点是否相同
if ((sX == eX) && (sY == eY))
{
return(result);
}
//判断起点终点横坐标是否相同
//判断起点终点纵坐标是否相同
int xDir = (eX > sX) ? 1 : (eX == sX) ? 0 : -1;
int yDir = (eY > sY) ? 1 : (eY == sY) ? 0 : -1;
//最简单的情况：一条线
if (getM(sX) == getM(eX) && getN(sY) == getN(eY))
{
float px = getM(sX) * itv + itv / 2 + rX;
float py = getN(sY) * itv + itv / 2 + rY;
result.AddPosition(new Position_Point(px, py));
}
else if (getM(sX) == getM(eX))
{
for (int i = getN(sY); (getN(eY) - i) * yDir >= 0; i += yDir)
{
float px = getM(sX) * itv + itv / 2 + rX;
float py = getN(sY) * itv + itv / 2 + rY;
result.AddPosition(new Position_Point(px, py));
}
}
else if (getN(sY) == getN(eY))
{
for (int i = getM(sX); (getM(eX) - i) * xDir >= 0; i += xDir)
{
float px = getM(sX) * itv + itv / 2 + rX;
float py = getN(sY) * itv + itv / 2 + rY;
result.AddPosition(new Position_Point(px, py));
}
}
//一般情况：斜线
float x = sX;
float y = sY;
float k = (eY - sY) / (eX - sX);
float nextX, nextY;
int offsetX = 0, offsetY = 0;
if (xDir > 0)
{
nextX = (getM(sX) + 1) * itv + rX;
}
else
{
nextX = getM(sX) * itv + rX;
}
if (yDir > 0)
{
nextY = (getN(sY) + 1) * itv + rY;
}
else
{
nextY = getN(sY) * itv + rY;
}
while ((eX - x) * xDir >= 0 || (eY - y) * yDir >= 0)
{
float px = (getM(x) + offsetX) * itv + itv / 2 + rX;
float py = (getN(y) + offsetY) * itv + itv / 2 + rY;
offsetX = offsetY = 0;
result.AddPosition(new Position_Point(px, py));
float dx = Math.Abs(nextX - x);
float dy = Math.Abs(nextY - y);
double dk = dy / dx;
if (dk > Math.Abs(k))
{
x = nextX;
if (xDir < 0)
{
offsetX = -1;
}
nextX += itv * xDir;
y = sY + (x - sX) * k;
}
else if (dk < Math.Abs(k))
{
y = nextY;
if (yDir < 0)
{
offsetY = -1;
}
nextY += itv * yDir;
x = sX + (y - sY) / k;
}
else
{
x = nextX;
y = nextY;
if (xDir < 0)
{
offsetX = -1;
}
if (yDir < 0)
{
offsetY = -1;
}
nextX += itv * xDir;
nextY += itv * yDir;
}
}
IList <IPosition> poslist = result.ToIlist();
//去掉重复点
for (int i = 0; i < poslist.Count - 1;)
{
if (poslist[i].GetX() == poslist[i + 1].GetX() && poslist[i].GetY() == poslist[i + 1].GetY())
{
poslist.RemoveAt(i + 1);
}
else
{
i++;
}
}
//去掉两个端点
poslist.RemoveAt(0);
poslist.RemoveAt(poslist.Count - 1);
return(result);
}