[Interest] sin wave with QPainterPath between two points

[Elvis Stansvik]

2017-07-20 10:30 GMT+02:00 Patrick Stinson <patrickkidd at gmail.com>:
> Also it should be between two arbitrary points, so the sine wave may go from
> top-right to bottom left, for example.

Right, but that's just a transformation of the bezier control points
once you have them.

Elvis

>
> On Jul 20, 2017, at 1:28 AM, Elvis Stansvik <elvstone at gmail.com> wrote:
>
> 2017-07-20 10:23 GMT+02:00 Jean-Michaël Celerier
> <jeanmichael.celerier at gmail.com>:
>
> You can just compute the sine directly :
>
>   for(int i = 0; i < width; i++)
>   {
>     int x = i;
>     int y = height / 2 + amplitude * std::sin(2 * M_PI * freq * i / width +
> phase);
>     path.lineTo(x, y);
>   }
>
>
> I think he wanted to avoid an approximation with straight lines and
> use cubic beziers.
>
> Jean-Michaël: There seems to be many pages explaining the theory
> behind sine approximation using Beziers if you Google.
>
> Elvis
>
>
>
>
>
>
> -------
> Jean-Michaël Celerier
> http://www.jcelerier.name
>
> On Thu, Jul 20, 2017 at 9:47 AM, Patrick Stinson <patrickkidd at gmail.com>
> wrote:
>
>
> Hello! I want to figure out how to draw a sin wave between two QPointF’s
> using QPainterPath. Calculating the cubic control points seems like the best
> way, but I am far from mastering that theory.
>
> This is a diagramming app and the goal is to get a squiggly line between
> two objects.
>
> Thanks!
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