topic Re: GDL: POLY2 Example with Arc? in Libraries & objects

GDL: POLY2 Example with Arc?

genarch — Thu, 01 Jun 2006 21:16:01 GMT

Could someone please provide working GDL code for a POLY2 command that gives a half circle? I just can't figure out the correct syntax for the POLY2 commands and it's driving me crazy!

Re: GDL: POLY2 Example with Arc?

Anonymous — Thu, 01 Jun 2006 22:04:00 GMT

Acording the GDL manual, POLY2 does not implement
additional status codes but POLY2_ does unless you have
a resol statement earlier in the script set to eight or less.
Peter Devlin

Re: GDL: POLY2 Example with Arc?

genarch — Thu, 01 Jun 2006 22:18:03 GMT

Okay, you got me on semantics... in any case, I'll just answer my own post:

FILL circ_fill ! fill setting
POLY2_ 6, 3,
0,0,1, ! node
-bcirc,0,1, ! node
1,90,800, ! set tangent (see Additional Status Codes)
bcirc,-180,2000, ! tangential arc by radius and angle
bcirc,0,1, ! node
0,0,1 ! repeat first node

Where "bcirc" is a dimension defined in the parameters. The result of the POLY2_ above give a half circle fill of radius "bcirc".

Re: GDL: POLY2 Example with Arc?

Anonymous — Mon, 05 Jun 2006 17:05:02 GMT

Your example:

FILL circ_fill
POLY2_ 6, 3,
0,0,15,
-bcirc,0,15,
0,90,815,
bcirc,-180,2015,
bcirc,0,15,
0,0,-1

another example

FILL circ_fill
POLY2_ 4,3,
bcirc,0,15,
0,0,915,
bcirc,180,4015,
bcirc,0,-1

CU mirco

Re: GDL: POLY2 Example with Arc?

Frank Beister — Tue, 06 Jun 2006 06:43:19 GMT

Or you can use this one:

FILL circ_fill
POLY2_ 3,1+2+4,
bcirc,0,1,
0,1,801,
-bcirc,0,1001

In your examples, you have used 15 for the status-values. This works, but is normally used for 3D-commands. In 2D status is defined with 0 or 1, what you should use.

To use a 4 in the mask (1+2+4) makes the last point superfluously.

@genarch
In your working example is the tangent IMHO not proper done, because it shouldn't have an x component. You have some needless points too.
It works proper like this:

POLY2_ 3, 1+2+4,
-bcirc,0,1,
0,1,801,
bcirc,-180,2001

And last possibility is

POLY2_ 3, 1+2+4,
-bcirc,0,1,
0,0,901,
bcirc,0,3001

Re: GDL: POLY2 Example with Arc?

Anonymous — Wed, 07 Jun 2006 07:33:49 GMT

In your examples, you have used 15 for the status-values. This works, but is normally used for 3D-commands. In 2D status is defined with 0 or 1, what you should use.

I know Frank but ....

what seems an error can become an advantage.

Put bcirc,0,15,
0,0,915,
bcirc,180,4015,
bcirc,0,-1

FILL circ_fill

POLY2_ nsp/3,3,
use (nsp)

PRISM_ nsp/3, ZZYZX,
get(nsp)

CU mirco

Re: GDL: POLY2 Example with Arc?

Frank Beister — Wed, 07 Jun 2006 07:43:16 GMT

That's right, but you set unused bits of the status, which might become in coming GDL-Versions a meaning. Maybe such old objects will not work proper anymore. It might be conservative, but I try to use the exact syntax.

I try to solve it like this:

IF GLOB_CONTEXT=2 THEN msk=1 ELSE msk=15

PUT bcirc,0,msk,
0,0,900+msk,
bcirc,180,4000+msk,
bcirc,0,-1