Commit Graph

81 Commits

Author SHA1 Message Date
Mike Reed
026d20f888 handle huge normalize requests (including non-finite x or y)
Bug: oss-fuzz:8023
Change-Id: I622b6e335d9efbe599fa9047b3a6fcee1664aa4a
Reviewed-on: https://skia-review.googlesource.com/124581
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2018-05-14 21:14:09 +00:00
Mike Klein
d8853ec0fd exact divide by 255 with NEON
Change-Id: Ib121eb0d5af1f22f48f517fe909112a77d92032e
Reviewed-on: https://skia-review.googlesource.com/113666
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Herb Derby <herb@google.com>
2018-03-14 02:38:52 +00:00
Mike Reed
f6188425c7 Extend math test to ensure our min/max/pin handle non-finites
Bug: skia:
Change-Id: I4fe544c32da071d161229b12f7b90a3296b0d499
Reviewed-on: https://skia-review.googlesource.com/112140
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2018-03-05 17:13:46 +00:00
Mike Reed
3d5a6b5f25 add saturate helper for float2int64
Bug: skia:
Change-Id: I157f8c047145874c4585ae870018163908389b26
Reviewed-on: https://skia-review.googlesource.com/102321
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
2018-01-31 21:21:36 +00:00
Mike Reed
e07622386b clone saturating cast code for doubles
Bug: skia:
Change-Id: I4f35413995cf73c6f130476d6b36e530120aa7ed
Reviewed-on: https://skia-review.googlesource.com/57901
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2017-10-10 19:58:13 +00:00
Cary Clark
a4083c97d4 make most of SkColorPriv.h private
created new file src/core/SkColorData.h for
internal consumption. Note that many of the
functions there are unused as well.

Bug: skia: 6898
R: reed@google.com
Change-Id: I25bfd5a9c21f53558c4ca65a77eb5d322d897c6d
Reviewed-on: https://skia-review.googlesource.com/46848
Commit-Queue: Cary Clark <caryclark@google.com>
Reviewed-by: Mike Reed <reed@google.com>
2017-09-15 16:31:35 +00:00
Mike Reed
828f1d5195 handle overflows in float->int
rects are already auto-vectorized, so no need to explicitly write a 4f version of SkRect::round()

Bug: skia:
Change-Id: I098945767bfcaa7093d770c376bd17ff3bdc9983
Reviewed-on: https://skia-review.googlesource.com/32060
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
2017-08-09 16:07:24 +00:00
Mike Reed
8addae8b53 just use math.h for converting from float to int
Bug: skia:
Change-Id: I40cce503cd4cef09c671511a705192efc5d67d71
Reviewed-on: https://skia-review.googlesource.com/31002
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2017-08-04 21:25:07 +00:00
Yuqian Li
ce1d293880 Add test for QuickFDot6Div
This test will catch our (1 << 10) bug (which should be 1 << 9)

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4986

Change-Id: I25b607d1535a647284cee3b304a6f567f389e7f6
Reviewed-on: https://skia-review.googlesource.com/4986
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Yuqian Li <liyuqian@google.com>
2016-11-18 17:16:49 +00:00
Robert Phillips
9e38047c56 Add GrNextSizePow2
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4069

BUG=skia:5882

Change-Id: Ib9af5918716be594c3c07239eca179dbb4eb8566
Reviewed-on: https://skia-review.googlesource.com/4069
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
2016-10-31 18:27:01 +00:00
liyuqian
3f490cc642 Make SkFixedRound/Ceil/FloorToFixed as inline func
The macros that we were using will return unsigned int32 instead of
signed int32 because of the last 0xFFFF0000 mask. That may bring
problems if we right shift that result.

Special thanks to mtklein@google.com for helping me find out this issue.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2433233003

Review-Url: https://chromiumcodereview.appspot.com/2433233003
2016-10-20 11:23:10 -07:00
mtklein
6a259bfcc8 Revert of My take on SkAlign changes. (patchset #3 id:40001 of https://codereview.chromium.org/2368293002/ )
Reason for revert:
Let's see if reverting this helps the roll.

Original issue's description:
> My take on SkAlign changes.
>
> Like the other change, it makes SkAlignN(x) macros work for pointers, and makes the macros themselves just syntax sugar for SkAlign<N>(x).  We can still decide if we want to sed away the macros independently.
>
> This just does it in a somewhat less repetitive way, and adds some tests.
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2368293002
>
> No public API changes.
> TBR=reed@google.com
>
> Committed: https://skia.googlesource.com/skia/+/e1a5f4e292384046678edc5c1e360b3e13dc118c

TBR=cblume@chromium.org,mtklein@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review-Url: https://codereview.chromium.org/2372083002
2016-09-26 18:20:57 -07:00
mtklein
e1a5f4e292 My take on SkAlign changes.
Like the other change, it makes SkAlignN(x) macros work for pointers, and makes the macros themselves just syntax sugar for SkAlign<N>(x).  We can still decide if we want to sed away the macros independently.

This just does it in a somewhat less repetitive way, and adds some tests.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2368293002

No public API changes.
TBR=reed@google.com

Review-Url: https://codereview.chromium.org/2368293002
2016-09-26 10:31:12 -07:00
liyuqian
0d2c234e44 Fix SkFixedDiv macro
Previously, the macro won't pass the unit test that I just added in this
CL.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2149733002

Review-Url: https://codereview.chromium.org/2149733002
2016-07-13 13:34:46 -07:00
mtklein
785a5b941a Clean up SkFloatBits
- remove dead code
- rewrite float -> int converters

The strategy for the new converters is:
   - convert input to double
   - floor/ceil/round in double space
   - pin that double to [SK_MinS32, SK_MaxS32]
   - truncate that double to int32_t

This simpler strategy does not work:
   - floor/ceil/round in float space
   - pin that float to [SK_MinS32, SK_MaxS32]
   - truncate that float to int32_t

SK_MinS32 and SK_MaxS32 are not representable as floats:
they round to the nearest float, ±2^31, which makes the
pin insufficient for floats near SK_MinS32 (-2^31+1) or
SK_MaxS32 (+2^31-1).

float only has 24 bits of precision, and we need 31.
double can represent all integers up to 50-something bits.

An alternative is to pin in float to ±2147483520, the last
exactly representable float before SK_MaxS32 (127 too small).

Our tests test that we round as floor(x+0.5), which can
return different numbers than round(x) for negative x.
So this CL explicitly uses floor(x+0.5).

I've updated the tests with ±inf and ±NaN, and tried to
make them a little clearer, especially using SK_MinS32
instead of -SK_MaxS32.

I have not timed anything here.  I have never seen any of these
methods in a profile.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2012333003

Review-Url: https://codereview.chromium.org/2012333003
2016-05-27 10:47:32 -07:00
brianosman
14f850abfe Remove Sk(Float|Double)PinToFixed functions, only used in tests.
These were triggering compile-time floating point overflow for one user,
and we don't use them.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1952303005

Review-Url: https://codereview.chromium.org/1952303005
2016-05-06 11:45:55 -07:00
benjaminwagner
70f1a6c64e Add pinned versions of *ToFixed.
BUG=skia:4632
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1707023002

Review URL: https://codereview.chromium.org/1707023002
2016-04-07 09:23:12 -07:00
benjaminwagner
6c71e0a065 Reverse dependency between SkScalar.h and SkFixed.h.
The following are unused in Chromium, Android, Mozilla, and Google3:
 - SkFixedToScalar
 - SkScalarToFixed

The following are additionally unused in Skia:
 - SkStrAppendFixed
 - SkWriteBuffer::writeFixed

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1841123002

Review URL: https://codereview.chromium.org/1841123002
2016-04-07 08:49:31 -07:00
halcanary
7d57124a2a Unit Tests: eliminate stray SkDebugf()s.
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1733113002

Review URL: https://codereview.chromium.org/1733113002
2016-02-24 17:59:16 -08:00
mtklein
a766ca87bf de-proc sk_float_rsqrt
This is the first of many little baby steps to have us stop runtime-detecting NEON.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1616013003
CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot

Committed: https://skia.googlesource.com/skia/+/efcc125acd2d71eb077caf6db65fdd6b9eb1dc0d

Review URL: https://codereview.chromium.org/1616013003
2016-01-26 07:40:30 -08:00
mtklein
ed814f34c7 Revert of de-proc sk_float_rsqrt (patchset #3 id:40001 of https://codereview.chromium.org/1616013003/ )
Reason for revert:
This is somehow blocking the Google3 roll in ways neither Ben nor I understand.  Precautionary revert... will try again Monday.

Original issue's description:
> de-proc sk_float_rsqrt
>
> This is the first of many little baby steps to have us stop runtime-detecting NEON.
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1616013003
> CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot
>
> Committed: https://skia.googlesource.com/skia/+/efcc125acd2d71eb077caf6db65fdd6b9eb1dc0d

TBR=reed@google.com,mtklein@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1629503002
2016-01-22 11:51:40 -08:00
mtklein
efcc125acd de-proc sk_float_rsqrt
This is the first of many little baby steps to have us stop runtime-detecting NEON.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1616013003
CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot

Review URL: https://codereview.chromium.org/1616013003
2016-01-22 08:49:26 -08:00
caryclark
3127c99986 ubsan shift fixes
Use an inline function that does a normal shift. When built for the sanitizer, add casts so that the shift is unsigned.

Also make a few fixes to do unsigned shifts or avoid the shift altogether; and add an argument spec to some macros.

R=reed@google.com,mtklein@google.com
BUG=skia:4633

Review URL: https://codereview.chromium.org/1503423003
2015-12-09 12:02:30 -08:00
jvanverth
29c69793f0 Update fallback rsqrt implementation to use optimal constants.
Improves max relative error from 0.00175126 to 0.000650197.
Also add unit tests to check error bounds.

BUG=chromium:511458

Review URL: https://codereview.chromium.org/1251423002
2015-07-23 11:14:29 -07:00
mtklein
97ca98d74e Let's find out what's up with the TSAN bot test failures.
BUG=skia:

Review URL: https://codereview.chromium.org/1020573002
2015-03-18 11:32:21 -07:00
jvanverth
936799204b Add float-to-half (binary16) conversion functions.
Based on code by Fabian Giesen at
https://fgiesen.wordpress.com/2012/03/28/half-to-float-done-quic/.

These will be needed for creating binary16 textures from floating point data.

BUG=skia:3103

Review URL: https://codereview.chromium.org/760753003
2014-11-26 13:15:59 -08:00
caryclark
38dd9f2e41 remove unused SkIntToFloatCast_NoOverflowCheck
R=reed@google.com, reed
BUG=skia:2849

Author: caryclark@google.com

Review URL: https://codereview.chromium.org/483273003
2014-08-19 07:39:41 -07:00
tfarina@chromium.org
8f6884aab8 Cleanup: Sanitize the order of includes under tests/
Initially this was to make sure Test.h appeared after the Sk*.h includes.

Patch generated by the following command line:

$ ~/chromium/src/tools/sort-headers.py tests/*.cpp

BUG=None
TEST=tests
R=robertphillips@google.com

Review URL: https://codereview.chromium.org/145313004

git-svn-id: http://skia.googlecode.com/svn/trunk@13177 2bbb7eff-a529-9590-31e7-b0007b416f81
2014-01-24 20:56:26 +00:00
commit-bot@chromium.org
e2eac8b2fd Move macros from TestClassDef.h to Test.h
Motivation: those macros don't make any sense without the definitions
in Test.h.

BUG=
R=mtklein@google.com

Author: halcanary@google.com

Review URL: https://codereview.chromium.org/138563004

git-svn-id: http://skia.googlecode.com/svn/trunk@13074 2bbb7eff-a529-9590-31e7-b0007b416f81
2014-01-14 21:04:37 +00:00
halcanary@google.com
a9325fa237 Add REPORTF test macro.
This macro replaces:
    SkString str;
    str.printf("Foo test Expected %d got %d", x, y);
    reporter->reportFailed(str);
with the shorter code:
    REPORTF(reporter, ("Foo test Expected %d got %d", x, y));

The new form also appends __FILE__:__LINE__ to the message before calling reportFailed().

BUG=
R=mtklein@google.com

Review URL: https://codereview.chromium.org/132843002

git-svn-id: http://skia.googlecode.com/svn/trunk@13016 2bbb7eff-a529-9590-31e7-b0007b416f81
2014-01-10 14:58:10 +00:00
reed@google.com
01c41a556e Revert "Revert "begin to remove SkLONGLONG and wean Skia off of Sk64""
This reverts commit 15b986baf026a3da5e2cac8106a1b753df242c39.

BUG=

Review URL: https://codereview.chromium.org/119353003

git-svn-id: http://skia.googlecode.com/svn/trunk@12796 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-12-20 14:24:21 +00:00
reed@google.com
b1560445c6 Revert "begin to remove SkLONGLONG and wean Skia off of Sk64"
This reverts commit 784890196fdab96289f9389db43aca01f35db0f9.

Revert "use LL suffix for 64bit literal"

This reverts commit 9634295aff9bffd7a3875a0ca4a9b1a27d0793fc.

BUG=

Review URL: https://codereview.chromium.org/116543009

git-svn-id: http://skia.googlecode.com/svn/trunk@12790 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-12-19 22:28:48 +00:00
reed@google.com
d6a301e9ad begin to remove SkLONGLONG and wean Skia off of Sk64
BUG=
R=caryclark@google.com

Review URL: https://codereview.chromium.org/99433009

git-svn-id: http://skia.googlecode.com/svn/trunk@12788 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-12-19 21:54:27 +00:00
reed@google.com
1915fd09f3 remove unused SkFixed and SkFract functions
BUG=
R=caryclark@google.com

Review URL: https://codereview.chromium.org/113873008

git-svn-id: http://skia.googlecode.com/svn/trunk@12767 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-12-19 14:22:03 +00:00
reed@google.com
8f4d2306fa remove SK_SCALAR_IS_[FLOAT,FIXED] and assume floats
To keep the CL (slightly) managable, this does not make any changes to
existing macros (e.g. SkScalarMul). Just tackling #ifdef constructs this
time around.

BUG=
R=bsalomon@google.com, caryclark@google.com

Review URL: https://codereview.chromium.org/117053002

git-svn-id: http://skia.googlecode.com/svn/trunk@12712 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-12-17 16:44:46 +00:00
tfarina@chromium.org
e4fafb146e Use DEFINE_TESTCLASS_SHORT macro in tests.
The three version of DEFINE_TESTCLASS macro is deprecated and thus just
use the simple, short one.

BUG=None
TEST=out/Debug/tests
R=mtklein@google.com, bsalomon@google.com, robertphillips@google.com

Review URL: https://codereview.chromium.org/100113004

git-svn-id: http://skia.googlecode.com/svn/trunk@12653 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-12-12 21:11:12 +00:00
commit-bot@chromium.org
4b413c8bb1 remove SkFloatToScalar macro
BUG=
R=reed@google.com, djsollen@google.com

Author: caryclark@google.com

Review URL: https://codereview.chromium.org/85463005

git-svn-id: http://skia.googlecode.com/svn/trunk@12385 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-11-25 19:44:07 +00:00
bungeman@google.com
fab44db294 Clean up SkTypes.h.
This change removes sk_stdint.h since it is only needed for vs2008 and earlier.
This change removes SK_MMAP_SUPPORT define since it is no longer used.
This change removes the stdio.h include from SkTypes.h since on many systems
this is a very large header, few Skia files actually use it, it is
available everywhere standard, and SkDebugf should be used instead.

After this change there is no need for external users to put Skia's
include/config into their own list of includes, saving the headache
of having two header files of the same name and sometimes getting the
wrong one depending on include order.

R=bsalomon@google.com, djsollen@google.com

Review URL: https://codereview.chromium.org/27044002

git-svn-id: http://skia.googlecode.com/svn/trunk@11738 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-10-11 18:50:45 +00:00
commit-bot@chromium.org
2c86fbb0b1 Add SkDivMod with a special case for ARM.
BUG=skia:1663
R=djsollen@google.com, tomhudson@google.com, reed@google.com

Author: mtklein@google.com

Review URL: https://chromiumcodereview.appspot.com/24159009

git-svn-id: http://skia.googlecode.com/svn/trunk@11482 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-09-26 19:22:54 +00:00
commit-bot@chromium.org
e0e7cfe44b Change old PRG to be SkLCGRandom; change new one to SkRandom
The goal here is to get people to start using the new random number
generator, while leaving the old one in place so we don't have to 
rebaseline GMs.

R=reed@google.com, bsalomon@google.com

Author: jvanverth@google.com

Review URL: https://chromiumcodereview.appspot.com/23576015

git-svn-id: http://skia.googlecode.com/svn/trunk@11169 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-09-09 20:09:12 +00:00
commit-bot@chromium.org
6485b0be74 Switch out random number generator for tests, benches, samples.
This change makes tests, benches and samples use the new SkMWCRandom PRNG. GMs will be saved for another time, as they'll require rebaselining.

R=reed@google.com, bsalomon@google.com

Author: jvanverth@google.com

Review URL: https://chromiumcodereview.appspot.com/23653018

git-svn-id: http://skia.googlecode.com/svn/trunk@11136 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-09-06 19:05:11 +00:00
robertphillips@google.com
0e6e8cc627 Revert r10705 (ARM Skia NEON patches - 04 - Clean SkFixed / SkLONGLONG) due to 1000+ linux_layout failures (http://build.chromium.org/p/tryserver.chromium/builders/linux_layout_rel/builds/18997/steps/webkit_tests/logs/stdio)
git-svn-id: http://skia.googlecode.com/svn/trunk@10729 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-08-15 13:43:23 +00:00
commit-bot@chromium.org
73ab296536 ARM Skia NEON patches - 04 - Clean SkFixed / SkLONGLONG
It removes SkLONGLONG and uses int64_t to implement the  SkFixed
operations for which a SkLONGLONG version existed. It also
removes the 32 bit version that are being replaced.

BUG=
R=djsollen@google.com, reed@google.com

Author: kevin.petit.arm@gmail.com

Review URL: https://chromiumcodereview.appspot.com/18539004

git-svn-id: http://skia.googlecode.com/svn/trunk@10705 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-08-14 11:43:52 +00:00
reed@google.com
c9f81661c1 add endian tests (reviewed by bungeman)
git-svn-id: http://skia.googlecode.com/svn/trunk@8993 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-05-03 18:06:31 +00:00
skia.committer@gmail.com
8152113073 Sanitizing source files in Skia_Periodic_House_Keeping
git-svn-id: http://skia.googlecode.com/svn/trunk@8919 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-04-30 07:01:03 +00:00
reed@google.com
bc57a29a7a add wacky random shift so I can generate some zeros (without the optimizer knowing)
so I can test passing a 0 to SkCLZ()



git-svn-id: http://skia.googlecode.com/svn/trunk@8904 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-04-29 15:27:42 +00:00
reed@google.com
7729534da4 reland 8897 (was not a build-breaker) and fix MathTest (was a build-breaker)
git-svn-id: http://skia.googlecode.com/svn/trunk@8899 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-04-29 14:43:50 +00:00
reed@google.com
c21f86fc91 add unittest for SkCLZ
git-svn-id: http://skia.googlecode.com/svn/trunk@8896 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-04-29 14:18:23 +00:00
reed@google.com
ea774d2a5a fix asserts in SkMulDiv255Round, and add test
Review URL: https://codereview.chromium.org/13934010

git-svn-id: http://skia.googlecode.com/svn/trunk@8813 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-04-22 20:21:56 +00:00
jvanverth@google.com
c490f801b0 Change random number generator for 'tests' to SkMWCRandom. Also removes some
unused headers and fixes a couple of bugs exposed by changing the random 
number generator:

First, the function SkMatrix::getMaxStretch() had an error where it was testing
the square of a number against near-zero. This led to it occasionally taking a
cheaper but imprecise path for computing the eigenvalues of the matrix. It's 
been replaced with a check against the square of SK_ScalarNearlyZero. 

The second case was a failure in ClipStackTest, where it hit the rare case of 
a practically empty clip stack (it has a single Union) and we set a tight 
bounds. The bounds rect doesn't get set by GrReducedClip::ReduceClipStack() in 
this case, so when it clips the reduced stack it's clipping against garbage, 
and the resulting regions don't match. The solution is to initialize the 
tightBounds rect.


git-svn-id: http://skia.googlecode.com/svn/trunk@7952 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-03-04 13:56:38 +00:00