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

5 files changed, 3 insertions, 5 deletions

diff --git a/src/core/SkFloat.cpp b/src/core/SkFloat.cpp
index b5cc4f18e7..721d8ec53e 100644
--- a/src/core/SkFloat.cpp
+++ b/src/core/SkFloat.cpp
@@ -291,7 +291,7 @@ void SkFloat::UnitTest()
     d.setAdd(c, b);
     SkDebugf("SkFloat: %d + %d = %d\n", c.getInt(), b.getInt(), d.getInt());
 
-    SkRandom    rand;
+    SkMWCRandom    rand;
 
     int i;
     for (i = 0; i < 1000; i++)
diff --git a/src/core/SkGraphics.cpp b/src/core/SkGraphics.cpp
index 873d5466da..8e7c7cd31d 100644
--- a/src/core/SkGraphics.cpp
+++ b/src/core/SkGraphics.cpp
@@ -19,7 +19,6 @@
 #include "SkPath.h"
 #include "SkPathEffect.h"
 #include "SkPixelRef.h"
-#include "SkRandom.h"
 #include "SkRefCnt.h"
 #include "SkRTConf.h"
 #include "SkScalerContext.h"
diff --git a/src/core/SkMatrix.cpp b/src/core/SkMatrix.cpp
index d420dd3b92..d9675f3979 100644
--- a/src/core/SkMatrix.cpp
+++ b/src/core/SkMatrix.cpp
@@ -1808,7 +1808,7 @@ SkScalar SkMatrix::getMaxStretch() const {
     SkScalar largerRoot;
     SkScalar bSqd = SkScalarMul(b,b);
     // if upper left 2x2 is orthogonal save some math
-    if (bSqd <= SK_ScalarNearlyZero) {
+    if (bSqd <= SK_ScalarNearlyZero*SK_ScalarNearlyZero) {
         largerRoot = SkMaxScalar(a, c);
     } else {
         SkScalar aminusc = a - c;
diff --git a/src/gpu/GrRedBlackTree.h b/src/gpu/GrRedBlackTree.h
index 2ccf77fb50..ba03be2950 100644
--- a/src/gpu/GrRedBlackTree.h
+++ b/src/gpu/GrRedBlackTree.h
@@ -950,7 +950,7 @@ void GrRedBlackTree<T,C>::UnitTest() {
     GrRedBlackTree<int> tree;
     typedef GrRedBlackTree<int>::Iter iter;
 
-    SkRandom r;
+    SkMWCRandom r;
 
     int count[100] = {0};
     // add 10K ints
diff --git a/src/gpu/gl/GrGLEffectMatrix.h b/src/gpu/gl/GrGLEffectMatrix.h
index 49ddceb129..1a11656534 100644
--- a/src/gpu/gl/GrGLEffectMatrix.h
+++ b/src/gpu/gl/GrGLEffectMatrix.h
@@ -12,7 +12,6 @@
 #include "SkMatrix.h"
 
 class GrTexture;
-class SkRandom;
 
 /**
  * This is a helper to implement a texture matrix in a GrGLEffect.