Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by address@hidden)

[thomasmorley65]

Let me split my reply into two.

This one about the current patch and how to proceed.

On 2015/10/20 14:25:21, dak wrote:
> I'm not really enthused about this approach even though it originates
from a
> proposal of mine.  It works basically by moving around problematic
angles,

exactly

> leading to discontinuities at multiples of PI/4 rather than just PI
being
> imprecise.

PI/2 is problematic as well (from scheme-sandbox):
guile> (cos (/ PI 2))
6.12323399573677e-17


I locally have a bunch of code, which I plan to turn into patches,
committing them in small pieces to ease review.

- simplified make-bezier-sandwich-stencil (already pushed)
- exact coord-rotate
- a generic make-bow-stencil, which _needs_ _exact_ coord-rotate
- the undertie-markup-command
- redefined make-parentheses-stencil
- a markup-command for drawing squiggle lines (under construction)
- a stencil-command to draw more fancy squiggle lines (under
construction)

All rely on make-bow-stencil.


I could
(a)
upload them, one after another, postponing a better coord-rotate (but
again, an exact coord-rotate for multiples of PI/2 is needed)
or
(b)
doing a better coord-rotate first (see next post)

What do you think?




https://codereview.appspot.com/269530043/