Add svg path arcto

Add svg path arcto

The arcto() used by SVG in Chrome and Android is ported here, using conics
instead of cubics. The logic is a direct transposition of the WebKit code.

The attached GM includes SVG that draws the same as Skia.

R=reed@google.com
BUG=skia:3959
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1613303002

Committed: https://skia.googlesource.com/skia/+/55d49053d1b6db42e013eb3409ffcfc7e235c685

[caryclark, 2016-01-21 18:39:16]

Description was changed from

==========
wip; add svg path arcto

BUG=skia:3959
==========

to

==========
wip; add svg path arcto

BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

[caryclark, 2016-01-22 18:48:25]

Description was changed from

==========
wip; add svg path arcto

BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

to

==========
wip; add svg path arcto

BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

[caryclark, 2016-01-22 18:50:53]

Description was changed from

==========
wip; add svg path arcto

BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

to

==========
Add svg path arcto

The arcto() used by SVG in Chrome and Android is ported here, using conics
instead of cubics. The logic is a direct transposition of the WebKit code.

The attached GM includes SVG that draws the same as Skia.

R=reed@google.com
BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

[caryclark, 2016-01-22 18:50:53]

caryclark@google.com changed reviewers:
+ reed@google.com

[caryclark, 2016-01-22 18:51:10]

Description was changed from

==========
Add svg path arcto

The arcto() used by SVG in Chrome and Android is ported here, using conics
instead of cubics. The logic is a direct transposition of the WebKit code.

The attached GM includes SVG that draws the same as Skia.

R=reed@google.com
BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

to

==========
Add svg path arcto

The arcto() used by SVG in Chrome and Android is ported here, using conics
 instead of cubics. The logic is a direct transposition of the WebKit code.

The attached GM includes SVG that draws the same as Skia.

R=reed@google.com
BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

[caryclark, 2016-01-22 18:51:35]

The CQ bit was checked by caryclark@google.com to run a CQ dry run

[commit-bot: I haz the power, 2016-01-22 18:51:41]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1613303002/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1613303002/80001

[caryclark, 2016-01-22 18:51:45]

Description was changed from

==========
Add svg path arcto

The arcto() used by SVG in Chrome and Android is ported here, using conics
 instead of cubics. The logic is a direct transposition of the WebKit code.

The attached GM includes SVG that draws the same as Skia.

R=reed@google.com
BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

to

==========
Add svg path arcto

The arcto() used by SVG in Chrome and Android is ported here, using conics
instead of cubics. The logic is a direct transposition of the WebKit code.

The attached GM includes SVG that draws the same as Skia.

R=reed@google.com
BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

[commit-bot: I haz the power, 2016-01-22 18:52:30]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-01-22 18:52:31]

Dry run: Try jobs failed on following builders:
  Build-Ubuntu-GCC-Mips-Debug-Android-Trybot on client.skia.compile (JOB_FAILED,
http://build.chromium.org/p/client.skia.compile/builders/Build-Ubuntu-GCC-Mip...)

[caryclark, 2016-01-22 18:56:29]

The CQ bit was checked by caryclark@google.com to run a CQ dry run

[commit-bot: I haz the power, 2016-01-22 18:56:30]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1613303002/100001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1613303002/100001

[commit-bot: I haz the power, 2016-01-22 18:59:33]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-01-22 18:59:34]

Dry run: Try jobs failed on following builders:
  Build-Win-MSVC-x86_64-Debug-Trybot on client.skia.compile (JOB_FAILED,
http://build.chromium.org/p/client.skia.compile/builders/Build-Win-MSVC-x86_6...)

[caryclark, 2016-01-22 19:07:35]

The CQ bit was checked by caryclark@google.com to run a CQ dry run

[commit-bot: I haz the power, 2016-01-22 19:07:44]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1613303002/120001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1613303002/120001

[commit-bot: I haz the power, 2016-01-22 19:20:22]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-01-22 19:20:22]

Dry run: This issue passed the CQ dry run.

[caryclark, 2016-01-22 19:23:32]

Please take a look.

[reed1, 2016-01-22 19:39:53]

lgtm w/ request for using Direction enum in api

https://codereview.chromium.org/1613303002/diff/120001/include/core/SkPath.h
File include/core/SkPath.h (right):

https://codereview.chromium.org/1613303002/diff/120001/include/core/SkPath.h#...
include/core/SkPath.h:510: *  @param sweep Determines if the arc should be swept
in an anti-clockwise (false) or
Can we use Direction enum for sweep, rather than a bool?

[caryclark, 2016-01-22 22:14:00]

https://codereview.chromium.org/1613303002/diff/120001/include/core/SkPath.h
File include/core/SkPath.h (right):

https://codereview.chromium.org/1613303002/diff/120001/include/core/SkPath.h#...
include/core/SkPath.h:510: *  @param sweep Determines if the arc should be swept
in an anti-clockwise (false) or
On 2016/01/22 19:39:53, reed1 wrote:
> Can we use Direction enum for sweep, rather than a bool?

This is a dilemma. Note that Direction assigns 0 to CW and 1 to CCW, while SVG
has decided that a sweep of 0 is CCW and a sweep of 1 is CW. 

We can be consistent and require the caller to 'not' their sweep parameter, but
that sounds like a recipe to get it wrong every time.

What do you think?

[reed1, 2016-01-22 22:46:31]

I think bool parameters are difficult always, and enum parameters are much
easier to read at the call-site.

I guess I'd prefer our API to be well documented (i.e. using an established enum
in this case) over "looking" like a spec. I think about our api as being beyond
any single spec, so I want our api to "make sense" and be clear regardless of
other possible specs.

I say all of that, assuming that was your question... if not, please ignore :)

[caryclark, 2016-01-23 12:21:59]

On 2016/01/22 22:46:31, reed1 wrote:
> I think bool parameters are difficult always, and enum parameters are much
> easier to read at the call-site.
> 
> I guess I'd prefer our API to be well documented (i.e. using an established
enum
> in this case) over "looking" like a spec. I think about our api as being
beyond
> any single spec, so I want our api to "make sense" and be clear regardless of
> other possible specs.
> 
> I say all of that, assuming that was your question... if not, please ignore :)

Yup, that was my question.

I assume that the bool for largeArc shoud be replaced by an enum as well.

I'll put together a CL.

[caryclark, 2016-01-23 12:53:34]

https://codereview.chromium.org/1613303002/diff/120001/include/core/SkPath.h
File include/core/SkPath.h (right):

https://codereview.chromium.org/1613303002/diff/120001/include/core/SkPath.h#...
include/core/SkPath.h:510: *  @param sweep Determines if the arc should be swept
in an anti-clockwise (false) or
On 2016/01/22 22:14:00, caryclark wrote:
> On 2016/01/22 19:39:53, reed1 wrote:
> > Can we use Direction enum for sweep, rather than a bool?
> 
> This is a dilemma. Note that Direction assigns 0 to CW and 1 to CCW, while SVG
> has decided that a sweep of 0 is CCW and a sweep of 1 is CW. 
> 
> We can be consistent and require the caller to 'not' their sweep parameter,
but
> that sounds like a recipe to get it wrong every time.
> 
> What do you think?

Made largeArc and sweep enums (Done.)

[caryclark, 2016-01-23 12:55:46]

The CQ bit was checked by caryclark@google.com

[caryclark, 2016-01-23 12:55:47]

The patchset sent to the CQ was uploaded after l-g-t-m from reed@google.com
Link to the patchset: https://codereview.chromium.org/1613303002/#ps140001
(title: "use enums for arcto's sweep and largeArc params")

[commit-bot: I haz the power, 2016-01-23 12:55:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1613303002/140001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1613303002/140001

[commit-bot: I haz the power, 2016-01-23 13:07:09]

Description was changed from

==========
Add svg path arcto

The arcto() used by SVG in Chrome and Android is ported here, using conics
instead of cubics. The logic is a direct transposition of the WebKit code.

The attached GM includes SVG that draws the same as Skia.

R=reed@google.com
BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

to

==========
Add svg path arcto

The arcto() used by SVG in Chrome and Android is ported here, using conics
instead of cubics. The logic is a direct transposition of the WebKit code.

The attached GM includes SVG that draws the same as Skia.

R=reed@google.com
BUG=skia:3959
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...

Committed:
https://skia.googlesource.com/skia/+/55d49053d1b6db42e013eb3409ffcfc7e235c685
==========

[commit-bot: I haz the power, 2016-01-23 13:07:10]

Committed patchset #8 (id:140001) as
https://skia.googlesource.com/skia/+/55d49053d1b6db42e013eb3409ffcfc7e235c685