Intersections between line and polygon

[sparklexiong]

Hello,

I am currently searching for a VI to fill the polygon shape with parallel line patterns. However, it seems there is no ready VI to use.

So I start to work from scratch. One core VI then would be find the intersections between a line and a polygon.

Indeed, I found Convex Polygon Intersection VI  (Shown in the Figure below) and Lines Intersection VI  which are not 100% fit my objective. Can anyone give some hints?

If there is no existing VI, I plan to bulid a VI that caculate line interesection with each line of a polygon, but I guess it would be computional expensive. 

Thank you for your comment either about the polygon fill with lines or intersections between a line and a polygon.

Sparkle

[Bob_Schor]

It is always helpful to attach a VI, even if you are just getting started and have very little code, as it will tell us some things about what you are doing.

So I'm going to assume (= "guess") that you are talking about 2D Pictures from the Graphics and Sound Palette.  If I were doing this, I would do it a little differently than you describe.

I'd start by drawing an image full of parallel lines (using the Draw Line function) -- this will become my "fill".  I'd use the Polygon information to create a Mask (keep everything inside the Polygon, clear everything outside the Polygon) and apply it to my "fill".  Add the polygon, itself, and you have a "filled polygon".  Repeat as needed.

Bob Schor

[aputman]

If you have MGI installed, the Coordinates palette has a 2D intersection of 2 lines VI.  You only have to supply the endpoints of the lines.

[Alexander_Sobolev]

Do you need their coordinates, or do you finally need to see a filled polygon as an image?

Look at mask features: draw lines over all image (or rectangle that covers all polygon), convert polygon into mask (ROI to mask, etc), apply mask, profit..

[sparklexiong]

Hello Alexander,

I have the coordinates of those polygon and I am thinking to use both ways : image processing tool or pure geometry algorithms.

After one day's work, I can realize some of my expectations now (see figure below). But it is still not as good as I want.

If some happens to know some basic algorithms which are easy to implement in LabVIEW or ready to use C library, I appreciate for the comment.

Best Regards,

sparkle 

[sparklexiong]

Dear Bob,

That is what I have done today. Thanks for the comment.

Best Regards,

Sparkle

[sparklexiong]

Hello Aputman,

Thanks for the comment. It is my first time to know that there are external function libraries existing. I will have a look tomrrow.

Best Reagrds,

Sparkle

[Majicoo]

Hello, can you send me this programm

[mprantl]

I have just released a couple of VIs for polygon clipping/growing/shrinking on VI package manager. The polygons are not restricted to convex polygons but can be arbitrary.  

The VIs can be found on VIP by searching for 4SmartMachines.