Use ARM fixes for SDF encoding.

Use ARM fixes for SDF encoding.

This pulls out the encoding fixes by Joel Liang from
https://codereview.chromium.org/1643143002/
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1726763002

Committed: https://skia.googlesource.com/skia/+/970fd1fbea16da013d5b103182d78499ed85f95f

[jvanverth1, 2016-02-23 18:06:24]

Description was changed from

==========
Use ARM fixes for SDF encoding.

This pulls out the encoding fixes by Joel Liang from
https://codereview.chromium.org/1643143002/
==========

to

==========
Use ARM fixes for SDF encoding.

This pulls out the encoding fixes by Joel Liang from
https://codereview.chromium.org/1643143002/
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

[jvanverth1, 2016-02-23 18:11:16]

jvanverth@google.com changed reviewers:
+ joel.liang@arm.com, robertphillips@google.com

[jvanverth1, 2016-02-23 18:11:17]

Joel, I pulled out just the encoding change into this patch so we can at least
get that in before Thursday.

[Joel.Liang, 2016-02-24 04:10:24]

https://codereview.chromium.org/1726763002/diff/20001/src/core/SkDistanceFiel...
File src/core/SkDistanceFieldGen.h (right):

https://codereview.chromium.org/1726763002/diff/20001/src/core/SkDistanceFiel...
src/core/SkDistanceFieldGen.h:23: // and the range is [-4, 4 - 1/255). Hence our
multiplier is 8 - 1/32 and zero threshold is 128/255.
The range here is wrong. It should be [-4, 4 * 127/128) or (-4 * 127/128, 4].
And we can also change the multiplier to 4 + 4 * 127/128 or 8 * 255/256 for
better understanding. (The result value is the same as 8 - 1/32)

[jvanverth1, 2016-02-24 14:57:13]

https://codereview.chromium.org/1726763002/diff/20001/src/core/SkDistanceFiel...
File src/core/SkDistanceFieldGen.h (right):

https://codereview.chromium.org/1726763002/diff/20001/src/core/SkDistanceFiel...
src/core/SkDistanceFieldGen.h:23: // and the range is [-4, 4 - 1/255). Hence our
multiplier is 8 - 1/32 and zero threshold is 128/255.
On 2016/02/24 04:10:23, Joel.Liang wrote:
> The range here is wrong. It should be [-4, 4 * 127/128) or (-4 * 127/128, 4].
> And we can also change the multiplier to 4 + 4 * 127/128 or 8 * 255/256 for
> better understanding. (The result value is the same as 8 - 1/32)

Fixed.

[Joel.Liang, 2016-02-24 15:24:13]

lgtm

[jvanverth1, 2016-02-24 16:16:35]

The CQ bit was checked by jvanverth@google.com

[commit-bot: I haz the power, 2016-02-24 16:16:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1726763002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1726763002/40001

[commit-bot: I haz the power, 2016-02-24 16:33:12]

Description was changed from

==========
Use ARM fixes for SDF encoding.

This pulls out the encoding fixes by Joel Liang from
https://codereview.chromium.org/1643143002/
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

to

==========
Use ARM fixes for SDF encoding.

This pulls out the encoding fixes by Joel Liang from
https://codereview.chromium.org/1643143002/
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...

Committed:
https://skia.googlesource.com/skia/+/970fd1fbea16da013d5b103182d78499ed85f95f
==========

[commit-bot: I haz the power, 2016-02-24 16:33:13]

Committed patchset #3 (id:40001) as
https://skia.googlesource.com/skia/+/970fd1fbea16da013d5b103182d78499ed85f95f