Fix rotation of shape forms

[jvoigtlaender]

Fixes https://github.com/elm-lang/core/issues/335.

Previously, something like

main : Signal Element
main = map (\t -> collage 500 500 [rotate (degrees t) (filled black (square 400))]) (every 20)

did not work since the t got to large for how rotation of Shape-Forms (as opposed to Element-Forms) is implemented.

[evancz]

Awesome, thank you!

[evancz]

Awesome, thank you!

[mgold]

Thanks Janis. Should I be worried about the cost of modulus every frame?

[mgold]

Thanks Janis. Should I be worried about the cost of modulus every frame?

[evancz]

I was thinking it may make sense to define twoPi or something, but I suspect the mod is fine.

[evancz]

I was thinking it may make sense to define twoPi or something, but I suspect the mod is fine.

[TheSeamau5]

You mean, tau? http://tauday.com/

[TheSeamau5]

You mean, tau? http://tauday.com/

[mgold]

+1 for tau!

[mgold]

+1 for tau!

[evancz]

@mgold, can you do a PR? I also know about tau, but I'd still like to call it twoPi because more people will know what it means.

[evancz]

@mgold, can you do a PR? I also know about tau, but I'd still like to call it twoPi because more people will know what it means.