MQL4: Price cross Gann grid?

Hi,
I made an indicator that automatically draws a Gann grid. I intended to use it in an EA, but then I realized that I have no way to find out where (in relation to the price) the Gann lines are.

For example if I have a Gann line drawn from Time[2]:$1.00 to Time[1] with a scale of 10 (1 for 4 digit brokers), how do I find out if the line has been crossed at Time[0]?

Here is the Gann indicator I made by the way.

Anyone have any idea? I am stumped on this.


Forget about the Gann line - imagine its a regular trendline. How do I know when the price crossed it?

I haven't actually coded this, but I have done similar things with Andrew's Pitchfork and Demark Trend Lines. Once you know any 2 points on the line, all other points can be determined by using the standard slope. So if 2 points are known, and the time (bar) is known, the price can be determined where the line intercepts the bar using the slope of the line.

With the others it is easy to compute the 2 points. With the Gann Grid, only one point is known. The way I would try to determine the second point is from the scale and the angle and the time (bar). Remember that the time difference isn't used in the calculation - it is the number of bars difference. It doesn't matter what you choose as the origin - the anchor of the grid would seem to be the most logical.

I'm not sure if this will work, but it is the approach I would use. This approach worked with the pitchfork and trend line, should work here as well.