detect intersection of diagonal line by current prices

[roland_nt]

Some NinjaScript indicator vendors offer a way to detect when prices cross or intersect a user specified diagonal line as the price bars are being formed, for example

http://www.tradingcoders.com/free-stuff/free-software.html

Can you give any hints on how this detection is done?
Note that the above mentioned indicator also allows the line to be moved to a new location on the screen thus detecting a possibly new intersection.
Thanks.

[Grasul]

Moving the line and detecting is out of my league, but if you new two points on the line, you could calculate the slope and track the value of the as a variable with each bar. I'm sure there is a more elegant way though.

[roland_nt]

The line is placed arbitrarily by the user so no points are known in advance. that is the crux of the problem. You really do have to detect where the line is. But thanks for trying.

[NinjaTrader_Bertrand]

You can detect this manual drawn lines with the DrawObjectsCollection available in NinjaScript -

http://www.ninjatrader.com/support/helpGuides/nt7/drawobjects.htm

[roland_nt]

detecting drawn object in interactive indicator

Bertrand:
Thanks for the hint. It was enough to work my way through the object collection docs and figure out how to interactively detect new objects.

The trick seems to be to watch for a change in objectCount in OnBarUpdate(). If the count goes up, a new object has appeared somewhere.

This is, additionally,the the closest thing to being able to interact with a running strategy/indicator to provide a.say. new price parameter value without going through a reload. One would draw a line on the screen and in the indicator/strategy check for objectCount change and then the value of EndY in the new Iline object and use that as the new parameter value. Not perfect for communicating new integers instead of prices but it's a start

Or is there an easier way?

[NinjaTrader_RyanM1]

Hi roland_nt,

I created a script that does much of what you're looking for. You're welcome to download and check out full source code here:

http://www.ninjatrader.com/support/forum/local_links.php?action=jump&catid=4&id=472

[roland_nt]

detecting drawn object in interactive indicator

Ryan:
Wow. Above and beyond the call of duty. Thanks ever so much for this quite thorough and useful skeleton.