Walter Zorn JS graphics library drawing not only axis aligned ellipse? 1

[mellthy]

Hello,

I'm experimenting with Walter Zorn's graphics library (

http://www.walterzorn.com/jsgraphics/jsgraphics_e.htm).

I wonder if there is a way how to draw ellipses that are not axis aligned. I've found a demo of rotation there too (

http://www.walterzorn.com/jsgraphics/demos/animarc.htm),

but looking into the code didn't give me an impression I could rotate ellipses.

Am I blind or just plain stupid?

Thanks for your opininons,
Mellthy

 

[BillyRayPreachersSon]

The demo is blanking out the previous shape and re-drawing it each frame with new parameters. So, could you not just do the same with your ellipse (i.e. draw it in the same place with your BG colour, and then in whatever FG colour you want but with new X- and Y-radii)?

Hope this helps,
Dan



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[feherke]

Hi

Dan, I think you misunderstood the requirement. Mellthy wants a rotated ellipsis. So the angle between the [red]ellipsis[/red]'s [green]axis[/green] and the coordinate system [blue]axis[/blue] is not multiple of 90.

[tt]
[blue]|[/blue] [green]/[/green]
[red]_,---.[/red]
[red],'[/red] [blue]|[/blue] [green]/[/green] [red]'.[/red]
[red]/[/red] [blue]|[/blue][green]/[/green] [red]|[/red]
[blue]--[/blue][red]/[/red][blue]----+----[/blue][red]/[/red][blue]--[/blue]
[red]|[/red] [green]/[/green][blue]|[/blue] [red]/[/red]
[red]`.[/red] [green]/[/green] [blue]|[/blue][red]_.'[/red]
[red]`---'[/red]
[green]/[/green] [blue]|[/blue]
[/tt]

As far as I saw, jsGraphics is not able to do that by default.

Feherke.

http://rootshell.be/~feherke/

 

[BillyRayPreachersSon]

You're right - I completely mis-understood the requirements.

Very nice ASCII graphic, BTW - how long did it take to draw?

Dan



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[BillyRayPreachersSon]

Hmm.. would it be possible to do it by breaking down the ellipse into smaller arcs and drawing those?

You'd have to calculate the start and end angles, etc, yourself... but it might just work.

Dan



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[feherke]

Hi

About 5-6 minutes both. ( The first one was too small... )

Well, I was close to suggest to draw it by "pixels", like I did it long time ago in Turbo Pascal... But I found no PutPixel in this library. Is over-optimized for efficient use of [tt]div[/tt]s.

Feherke.

http://rootshell.be/~feherke/