RE: Drawing an Arc at an angle.
On Thu, 08 Jan 2004 09:44:31 -0500, [EMAIL PROTECTED] (Zentara)
wrote:
On Wed, 7 Jan 2004 10:53:20 -0600, [EMAIL PROTECTED] (Dan Muey)
wrote:
Thanks! Even more to add to my look into list!
Yeah upon futher thought, you probably could use the Tk::Canvas and
actually plot your curve point-by-point from the equation of an
ellipse, rather than using the Oval function. Then export the
postscript.
Run the widget demo, there are 2 examples for plot, one of them
exports ps.
I'm not trying to hijack your thread, but the idea of
No sweat! I can use all the ideas I can get. I think this is a pretty good one you
have.
rotated ellipse sort of appeals to me. So here is a simple
postscript file to make a rotated ellipse. Just save as a .ps
file and look at it with ghostview. Now all you have to do,
is play with it to see how to align it up, to your needs,
then in your perl script, use a here doc to write it out to a
file. Then use Image Magick or Imager to convert it to .jpg
or whatever.
I got this from this page:
http://www.redgrittybrick.org/postscript/ellip se.html
%!PS-Adobe
%%Pages: 1
%%BoundingBox: 60 420 490
740
%
% canonical ellipse routine
% credit: Holger Gehringer
%
/inch { 72 mul } def
/ellipse {
/endangle exch def
/startangle exch def
/yrad exch def
/xrad exch def
/y exch def
/x exch def
/savematrix matrix currentmatrix def
x y translate
xrad yrad scale
0 0 1 startangle endangle arc
savematrix setmatrix
} def
%%Page: One 1
1 0 0 setrgbcolor
4 inch 8 inch translate
30 rotate
0 0 2.8 inch 1.4 inch 0 360 ellipse
16 setlinewidth
stroke
showpage
%%EOF
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RE: Drawing an Arc at an angle.
On Tue, 6 Jan 2004 11:03:14 -0600, [EMAIL PROTECTED] (Dan Muey) wrote: Dan Muey wrote: I've made a funtion to calculate the Fresnal zone for wireless connections. What I'd like to do is generate an image based on that. Something like the example at: http://ydi.com/calculation/fresnel-zone.php However the two connected points are rarely going to be at the same level so I'd need to draw the elipse At an angle instead of horizontally. GD's elipse or arc function will probably do what I want but it seems all I can specify are the center point and width and height. Is there a way to also specify the x/y of each point on the left and right side of the elipse? Make sense? Yes, but you're out of luck I'm afraid Dan. The best I can suggest is that you use the 'filledPolygon' method and do the maths yourself. (Sorry, that's 'math' over there isn't it.) Have you thought about trying to do this on a Tk canvas? The oval item lets you specify the diagonal corners of the oval's bounding box. Tk::canvas can export itself as postscript, so you could do your drawing, export it as ps, then convert it to whatever format you want. Interesting I'm really workign on a dynamic system though, enter data into form and image is generated. I wonder if those steps would be a bit rough that way.. I don't know, I'll look into it for sure. Actually I guess I could do Tk::canvas save it to a temp .ps file and open the tmep file with GD or Imager or somethgin and conevrt it on the fly I guess it's not too impossible after all, I'll add this to my list of trick to try. Thanks! Dan -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
RE: Drawing an Arc at an angle.
On Wed, 7 Jan 2004 08:55:56 -0600, [EMAIL PROTECTED] (Dan Muey) wrote: Have you thought about trying to do this on a Tk canvas? The oval item lets you specify the diagonal corners of the oval's bounding box. Tk::canvas can export itself as postscript, so you could do your drawing, export it as ps, then convert it to whatever format you want. Interesting I'm really workign on a dynamic system though, enter data into form and image is generated. I wonder if those steps would be a bit rough that way.. I don't know, I'll look into it for sure. Actually I guess I could do Tk::canvas save it to a temp .ps file and open the tmep file with GD or Imager or somethgin and conevrt it on the fly I guess it's not too impossible after all, I'll add this to my list of trick to try. Thanks! Oops, I just tried it. The plain Tk::Canvas dosn't support rotation yet. And the Oval bounding box only does x-y alignment. The Tk::Zinc canvas does do rotation, but outputting postscript is still on the planned to do list. ;-( Zinc can make just about anything you want, with clipping, zooming, and rotations. But without the ps output, you would have to capture it manually. Just for fun, I tried tuxpaint, and it does make ellipses which can be rotated with the mouse, but I don't think it has a programming interface. Maybe something in script-fu with Gimp? There is an enormous number of scripts for script-fu. I did a groups.google.com search for rotate ellipse GD and there seems to be alot of C code to do it with the real GD c libs. Maybe you could get one to compile and call it from your perl script, passing your parameters to it? Or maybe you could do it programmatically by learning to write postscript directly from perl? Zinc makes it real easy to do it, and as a matter of fact, someone on the Zinc maillist today, just asked the developer to get going on the postscript output. I've even made a lobe shape programmatically with Zinc, and it's bezier curves. Good luckall my ideas are done. :-) Thanks! Even more to add to my look into list! -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
RE: Drawing an Arc at an angle.
Dan Muey wrote: I've made a funtion to calculate the Fresnal zone for wireless connections. What I'd like to do is generate an image based on that. Something like the example at: http://ydi.com/calculation/fresnel-zone.php However the two connected points are rarely going to be at the same level so I'd need to draw the elipse At an angle instead of horizontally. GD's elipse or arc function will probably do what I want but it seems all I can specify are the center point and width and height. Is there a way to also specify the x/y of each point on the left and right side of the elipse? Make sense? Yes, but you're out of luck I'm afraid Dan. The best I can suggest is that you use the 'filledPolygon' method and do the maths yourself. (Sorry, that's 'math' over there isn't it.) Where is your over there in relation to my over hear (St. Louis , MO USA)? I'm doing all the math(s) :), I'm only seeing a way to draw the elipse or arc with a horizontal and vertical orientation only. I'll test some things out a bit more and show the group what's happening and have some url's. Cheers, Rob -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
Re: Drawing an Arc at an angle.
On January 2, 2004 05:22 pm, Dan Muey wrote: Hello List, I've made a funtion to calculate the Fresnal zone for wireless connections. What I'd like to do is generate an image based on that. Something like the example at: http://ydi.com/calculation/fresnel-zone.php However the two connected points are rarely going to be at the same level so I'd need to draw the elipse At an angle instead of horizontally. GD's elipse or arc function will probably do what I want but it seems all I can specify are the center point and width and height. Is there a way to also specify the x/y of each point on the left and right side of the elipse? Make sense? Must the image be entirely made within GD? You can easily create a rotated ellipse via xfig. That is, you can use your perl script to make the .fig file and then cconvert the fig file to other graphics formats. It's jumping through hoops, but it should be straightforward. All you need to make the .fig file is (i) coordinates of the ellipse center, (ii) major/minor radii, and (iii) angle of rotation. TIA Dan -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
Re: Drawing an Arc at an angle.
Dan Muey wrote: I've made a funtion to calculate the Fresnal zone for wireless connections. What I'd like to do is generate an image based on that. Something like the example at: http://ydi.com/calculation/fresnel-zone.php However the two connected points are rarely going to be at the same level so I'd need to draw the elipse At an angle instead of horizontally. GD's elipse or arc function will probably do what I want but it seems all I can specify are the center point and width and height. Is there a way to also specify the x/y of each point on the left and right side of the elipse? Make sense? Yes, but you're out of luck I'm afraid Dan. The best I can suggest is that you use the 'filledPolygon' method and do the maths yourself. (Sorry, that's 'math' over there isn't it.) Cheers, Rob -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
Re: Drawing an Arc at an angle.
Rob Dixon wrote: Dan Muey wrote: I've made a funtion to calculate the Fresnal zone for wireless connections. What I'd like to do is generate an image based on that. Something like the example at: http://ydi.com/calculation/fresnel-zone.php However the two connected points are rarely going to be at the same level so I'd need to draw the elipse At an angle instead of horizontally. GD's elipse or arc function will probably do what I want but it seems all I can specify are the center point and width and height. Is there a way to also specify the x/y of each point on the left and right side of the elipse? Make sense? Yes, but you're out of luck I'm afraid Dan. The best I can suggest is that you use the 'filledPolygon' method and do the maths yourself. There is another, more straightforward possibility here. Not *that* straightforward, I'm afraid | ;-o) but conceptually so. I'm not sure about GD [I've never been able to get GD to load on my Win2K box] but if you use a builtin to calculate an ellipse of the right dimension, you could then use some basic angular rotation of the base shape. It certainly is not quick, which is probably why even high-end graphics applications seem to lack facilities for drawing such ellipses, but it can be pretty clear. Unfortunately, I have done very little in the way of mathematical operations in Perl, so I don't really know what functions Perl offers readily. Certainly an arctangent function could make this real swift. It might help to convert your locus to polar coordinates once the base ellipse is generated, then rotate it, then convert back to Cartesian. I must say, it's a question that has sorta gnawed at me ever since my first encounter with Win 3.11 PaintBrush. Joseph (Sorry, that's 'math' over there isn't it.) Boy, you do like to raise the interesting liguistic [ergo philosophical] points, huh? I'm firmly straddling the fence on this one. So is mathematics a collection of discrete studies, or a many-faceted exploration in the quest for fgood 'ol capital-T Truth...? [...wandering off, eyes fixed on some distant horizon...] -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
