[Cuis-dev] Best way to draw arcs

[Jon Hylands]

Hilaire,

Thanks for the input.

I've attached that method, with the #arcTo: sends.

This is what I get:

[image: usingArcTo.png]

If I replace the #arcTo: sends with the commented out #lineTo: sends (from
the attached code), this is what I get:

[image: usingLineTo.png]

So I know that I am specifying all the end points correctly.

Any ideas?

- Jon


On Sat, 4 Mar 2023 at 03:33, Hilaire Fernandes via Cuis-dev <
cuis-dev at lists.cuis.st> wrote:

> Hi Jon,
>
> Your gauges look very sweet!
>
> See attached file out of a Morph to give you an idea how to draw your
> green arc.
>
> [image: arc]
>
>
> Adjust accordingly to yours needs.
> Hilaire
>
>
> Le 04/03/2023 à 01:36, Jon Hylands via Cuis-dev a écrit :
>
> Sujet :
> [Cuis-dev] Best way to draw arcs
>
> De :
> Jon Hylands via Cuis-dev <cuis-dev at lists.cuis.st> <cuis-dev at lists.cuis.st>
>
> Date :
> 04/03/2023 01:36
>
> Pour :
> cuis-dev at lists.cuis.st
>
> Copie à :
> Jon Hylands <jhylands at gmail.com> <jhylands at gmail.com>
>
> Hi everyone,
>
> New to the list, new to Cuis (just downloaded it today).
>
> I'm designing some gauges for an ultralight plane that will run on a
> Raspberry Pi 4 with a 10" LCD panel. Right now, this is what I have:
>
> [image: Cuis-Gauges.png]
>
> I love the anti-aliasing, vector-based properly scalable graphics!
>
> The part that I'm not happy with is the green, yellow and red indicator
> bands on the airspeed gauge. They look nice, but I'm drawing them by
> drawing a sequence of filled polygons.
>
> The code looks like this:
>
> drawShadeFrom: startSpeed to: endSpeed color: color on: aCanvas
>   | ratio |
>   ratio := self angleToValueRatio.
>   aCanvas strokeWidth: 1 color: color fillColor: color do: [
>     startSpeed to: endSpeed - 2 do:[:each |
>       | startAngle endAngle |
>       startAngle := (90 - (each * ratio)) degreesToRadians.
>       endAngle := (90 - ((each + 2) * ratio) degreesToRadians.
>       aCanvas
>         moveTo: (Point rho: 85 theta: startAngle);
>         lineTo: (Point rho: 95 theta: startAngle);
>         lineTo: (Point rho: 95 theta: endAngle);
>         lineTo: (Point rho: 85 theta: endAngle);
>         lineTo: (Point rho: 85 theta: startAngle)]].
>
> I tried using the #arcTo: method, but I just couldn't get it to work at
> all (not to mention the line ends of the arc are round, which doesn't work
> here anyways).
>
> Is there a more reasonable way to do this?
>
> Thanks,
> Jon
>
>
> --
> Cuis-dev mailing listCuis-dev at lists.cuis.sthttps://lists.cuis.st/mailman/listinfo/cuis-dev
>
> --
> GNU Dr. Geohttp://drgeo.euhttp://blog.drgeo.eu
>
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