clamp fixed divide to 32 bits

clamp fixed divide to 32 bits

In SkEdge::setLine, the numerator is a 26.6 fixed number.
SkFixedDiv shifts it up by an additional 16 bits. If the
y interval is small, the result overflows 32 bits.

The code pins in 64 bit space before down-casting the result.

R=reed@google.com
BUG=skia:4708
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1583453002

Committed: https://skia.googlesource.com/skia/+/c63a0f8fe534eef8d52abc2066126729be9b497c

[caryclark, 2016-01-12 14:21:45]

Description was changed from

==========
clamp fixed divide to 32 bits

In SkEdge::setLine, the numerator is a 26.6 fixed number.
SkFixedDiv shifts it up by an additional 16 bits. If the
y interval is small, the result overflows 32 bits.

The code pins in 64 bit space before down-casting the result.

R=reed@google.com
BUG=skia:4708
==========

to

==========
clamp fixed divide to 32 bits

In SkEdge::setLine, the numerator is a 26.6 fixed number.
SkFixedDiv shifts it up by an additional 16 bits. If the
y interval is small, the result overflows 32 bits.

The code pins in 64 bit space before down-casting the result.

R=reed@google.com
BUG=skia:4708
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

[reed1, 2016-01-12 15:03:02]

lgtm

[caryclark, 2016-01-12 15:08:21]

The CQ bit was checked by caryclark@google.com

[commit-bot: I haz the power, 2016-01-12 15:08:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1583453002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1583453002/1

[commit-bot: I haz the power, 2016-01-12 15:21:21]

Description was changed from

==========
clamp fixed divide to 32 bits

In SkEdge::setLine, the numerator is a 26.6 fixed number.
SkFixedDiv shifts it up by an additional 16 bits. If the
y interval is small, the result overflows 32 bits.

The code pins in 64 bit space before down-casting the result.

R=reed@google.com
BUG=skia:4708
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

to

==========
clamp fixed divide to 32 bits

In SkEdge::setLine, the numerator is a 26.6 fixed number.
SkFixedDiv shifts it up by an additional 16 bits. If the
y interval is small, the result overflows 32 bits.

The code pins in 64 bit space before down-casting the result.

R=reed@google.com
BUG=skia:4708
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...

Committed:
https://skia.googlesource.com/skia/+/c63a0f8fe534eef8d52abc2066126729be9b497c
==========

[commit-bot: I haz the power, 2016-01-12 15:21:22]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/c63a0f8fe534eef8d52abc2066126729be9b497c