[comp.graphics] GKS

pramodmm@milton.u.washington.edu (Pramod Mahadev) (05/09/91)

Hello GKS experts!
this is a total novice posting a simple problem.
the problem is as follows
I would like to draw lines using GKS and I am using 
the subroutine in FORTRAN-77 called GPL. I have to draw
lines of different linewidths on the same workstation
viewport. I tried setting the aspect source flag to
bundled so that whenever I call the routine ,the line
will have a linewidth specified by the routine set line width
space factor.But I still get the same line widths for all
lines. 
It would be nice of you ,if you could tell me how to acheive
this and what should be the coordinate system to indicate the
line-width spacing 
Thanks in advance.
Pramod M.Mahadev
pramodmm@milton.u.washington.edu
 

mark@wimsey.bc.ca (Mark Sun) (05/10/91)

In article <1991May9.002543.1681@milton.u.washington.edu> pramodmm@milton.u.washington.edu (Pramod Mahadev) writes:
>Hello GKS experts!
>this is a total novice posting a simple problem.
>the problem is as follows
>I would like to draw lines using GKS and I am using 
>the subroutine in FORTRAN-77 called GPL. I have to draw
>lines of different linewidths on the same workstation
>viewport. I tried setting the aspect source flag to
>bundled so that whenever I call the routine ,the line
>will have a linewidth specified by the routine set line width
>space factor.But I still get the same line widths for all
>lines. 
>It would be nice of you ,if you could tell me how to acheive
>this and what should be the coordinate system to indicate the
>line-width spacing 
>Thanks in advance.
>Pramod M.Mahadev
>pramodmm@milton.u.washington.edu
> 

Pramod:

If you simply would like to draw lines of different widths, you should
precede the POLYLINE call (GPL) with a call to the SET_PLINE_LINEWIDTH 
function which is GSLWSC in the FORTRAN binding.  Your workstation will then
try to draw a line in the width specified in the GSLWSC call.

i.e.
     CALL GSLWSC( XLineWidth)
     CALL GPL( NPoints, Px, Py)

The line width is a real value with 1.0 usually representing the thinnest line
the workstation can display.  Setting the value to 2.0 will display twice this 
width IF the workstation is able.

The above approach sets the INDIVIDUAL attribute of a polyline. BUNDLED 
attributes are primarily used when you wish to change an attribute
(colour, width, line_type) dynamically when the line is stored as a segment.
If this is what you would like to do, e-mail me.

Hope this helps you!

Mark Sun                                    mark@wimsey.bc.ca
Genetek Earth Research Corporation          (604) 921-6807
P.O. Box 517
Lions Bay (Vancouver), B.C., CANADA
V0N 2E0

pramodmm@milton.u.washington.edu (Pramod Mahadev) (06/29/91)

Hello GKS Xperts
I have a small problem with the coordinate systems .
When my program reads the locator position instead
of the position i.e x and y coordinates being in
world coordinates ; they are in device coordinates.
Please enlighten me as to how to get the program output
world coordinates instead of either DC or NDC coordinates
I am using the subroutine GRQLC(wkid,lcdnr,stat,tnr,px,py)
where px and py are supposed to be in world coordinates but
my program returns device coordinates.

Thanks in advance 
Have Fun
Pramod M.Mahadev
pramodmm@milton.u.washington.edu

steve@groucho.ucar.edu (Steve Emmerson) (06/29/91)

In <1991Jun28.223326.28405@milton.u.washington.edu> pramodmm@milton.u.washington.edu (Pramod Mahadev) writes:

>Hello GKS Xperts
>I have a small problem with the coordinate systems .
>When my program reads the locator position instead
>of the position i.e x and y coordinates being in
>world coordinates ; they are in device coordinates.
>Please enlighten me as to how to get the program output
>world coordinates instead of either DC or NDC coordinates
>I am using the subroutine GRQLC(wkid,lcdnr,stat,tnr,px,py)
>where px and py are supposed to be in world coordinates but
>my program returns device coordinates.

If GRQLC() is returning OK rather than NONE, then the response should be
in world co-ordinates, and not normalized device co-ordinates.  I believe
anything else indicates a bug in your GKS implementation.

Credentials: I maintain XGKS.  (That and 35 cents gets me a cup of coffee.
;-)

Steve Emmerson        steve@unidata.ucar.edu        ...!ncar!unidata!steve