Implement arcTo()

[tj]

No description provided.

[RandomEtc]

I have an initial version of this working. It's a lot of math. The kind of work that makes me think I've done it wrong, but then I remember that this is why there aren't that many finished graphics libraries...

The only changes to my master branch are for arcTo if you want to take a look the specific commits are RandomEtc/node-canvas@cfc497e and RandomEtc/node-canvas@30d342b

I borrowed example/arcTo.js from http://canvex.lazyilluminati.com/misc/arcto.html which covers several edge cases (backwards arcs, colinear control points, etc).

It might be worth borrowing from http://philip.html5.org/demos/canvas/arcto-inf.html too, which should look like http://philip.html5.org/demos/canvas/arcto-inf.png

[tj]

wicked thanks man, I will take a look and merge shortly.

[RandomEtc]

I'm porting that other demo now, FYI.

[RandomEtc]

OK, they all fail :)

Better hold off on that merge!

(Also I just realized I overwrote my previous test... I'll be in touch)

RandomEtc/node-canvas@d3e7be7

[tj]

ahaha k :) let me know

[RandomEtc]

OK, I think I got a bit carried away with one of my tests. I'm calculating the control points correctly but I'm not catching some of the edge cases that the browser versions handle. I've got a test for triangle insideness in there which doesn't seem to be necessary, and something else needs to trigger that case instead.

Here's how Webkit does it with Cairo:
http://trac.webkit.org/browser/trunk/WebCore/platform/graphics/cairo/PathCairo.cpp#L160

And here's Chromium with Skia:
http://www.google.com/codesearch/p?hl=en#OAMlx_jo-ck/src/third_party/skia/src/core/SkPath.cpp&q=file:%28/|^%29Path\.h$%20package:%22chromium%22&gs=cpp:SkPath::arcTo%28float,%2520float,%2520float,%2520float,%2520float%29@chrome/trunk/src/third_party/skia/include/core/SkPath.h%257Cdecl&gsn=arcTo&l=670

I'll have to put this down for now. Sorry for false alarm!

[tj]

Added arcTo(). Closed by ea4b13e

[tj]

went with a slightly modified version of the webkit one, thanks for pointing it out

[RandomEtc]

Awesome, glad you got it working!