🚀 go-pugleaf

Hey,

at the moment I'm working with IV3.1beta2.

My problem is the following:

I'm writing the pick function for an InputHandler (GoalLine).
The InputHandler is a line from one of the upper corners to one
of the down corners of the allocation.

I want to make the target only if the mouse button is pressed at
a line position with a given epsilon (+- 10).

The problem is, if the line has a little gradient the difference 
between the real point and the display point is to big.

I've tested the to_pixels function of Canvas but it doesn't work.
Perhaps I'm making something wrong.

Who can help me ??


Thank's in advance,

	Joerg			(ringel@forwiss.uni-passau.de)


Here is the function:

---------------------------------------------------------------

void GoalLine::pick(Canvas* c, const Allocation& a, int depth, Hit& h) {

Coord		act_x = h.event()->pointer_x();
Coord		act_y = h.event()->pointer_y();
Coord		y1 = a.top();
Coord		y2 = a.bottom();
Coord		x1;
Coord		x2;

  Coord top_x = to_node->father()->x_coord();
  Coord bottom_x = to_node->x_coord();
  if (Math::abs(top_x - bottom_x) < 1.0) {
    x1 = x2 = a.x();
  }
  else {
    if (top_x < bottom_x) {
      x1 = a.left();
      x2 = a.right();
    }
    else {
      x1 = a.right();
      x2 = a.left();
    }
  }
  Coord diff_x = x2 - x1;
  Coord diff_y = y2 - y1;

  if (diff_x == 0 || diff_y == 0) {
    if (diff_x == 0) {
      if (Math::equal(x1, act_x, epsilon) && act_y < y1 && act_y > y2) {
        h.target(depth, this, 0, handler());
      }
    }
    else {
      if (Math::equal(y1, act_y, epsilon) &&
          act_y < Math::max(x1, x2) &&
          act_y > Math::min(x1, x2)) {
        h.target(depth, this, 0, handler());
      }
    }
  }
  else {
    Coord steigung1 = (diff_x / diff_y);
    Coord x_on_line = x1 + steigung1 * (act_y - y1);
    if (Math::equal(x_on_line, act_x, epsilon)) {
      Coord steigung2 = (diff_y / diff_x);
      Coord y_on_line = y1 + steigung2 * (act_x - x1);
      if (Math::equal(y_on_line, act_y, epsilon)) {
        h.target(depth, this, 0, handler());
      }
    }
  }
}