Core skia changes to prepare for Gr AA Hairline renderer

Review URL: http://codereview.appspot.com/4940045/



git-svn-id: http://skia.googlecode.com/svn/trunk@2160 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 24 insertions, 16 deletions

diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index e0d5b69cb8..e3eda6b7f4 100644
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -1419,21 +1419,11 @@ void SkPath::validate() const {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-/**
- *  Returns -1 || 0 || 1 depending on the sign of value:
- *  -1 if value < 0
- *   0 if vlaue == 0
- *   1 if value > 0
- */
-static int SkScalarSign(SkScalar value) {
-    return value < 0 ? -1 : (value > 0);
-}
-
 static int sign(SkScalar x) { return x < 0; }
 #define kValueNeverReturnedBySign   2
 
 static int CrossProductSign(const SkVector& a, const SkVector& b) {
-    return SkScalarSign(SkPoint::CrossProduct(a, b));
+    return SkScalarSignAsInt(SkPoint::CrossProduct(a, b));
 }
 
 // only valid for a single contour
diff --git a/src/core/SkPoint.cpp b/src/core/SkPoint.cpp
index 2ad171fc89..d6e6b318bf 100644
--- a/src/core/SkPoint.cpp
+++ b/src/core/SkPoint.cpp
@@ -359,7 +359,25 @@ bool SkPoint::setLength(SkFixed ox, SkFixed oy, SkFixed length) {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-SkScalar SkPoint::distanceToLineSegmentBetweenSqd(const SkPoint& a, 
+SkScalar SkPoint::distanceToLineBetweenSqd(const SkPoint& a,
+                                           const SkPoint& b,
+                                           Side* side) const {
+
+    SkVector u = b - a;
+    SkVector v = *this - a;
+    
+    SkScalar uLengthSqd = u.lengthSqd();
+    SkScalar det = u.cross(v);
+    if (NULL != side) {
+        SkASSERT(-1 == SkPoint::kLeft_Side &&
+                  0 == SkPoint::kOn_Side &&
+                  1 == kRight_Side);
+        *side = (Side) SkScalarSignAsInt(det);
+    }
+    return SkScalarMulDiv(det, det, uLengthSqd);
+}
+
+SkScalar SkPoint::distanceToLineSegmentBetweenSqd(const SkPoint& a,
                                                   const SkPoint& b) const {
     // See comments to distanceToLineBetweenSqd. If the projection of c onto
     // u is between a and b then this returns the same result as that 
diff --git a/src/views/SkTouchGesture.cpp b/src/views/SkTouchGesture.cpp
index bcfaf892c5..31adc74b38 100644
--- a/src/views/SkTouchGesture.cpp
+++ b/src/views/SkTouchGesture.cpp
@@ -28,8 +28,8 @@ static double getseconds() {
 }
 
 // returns +1 or -1, depending on the sign of x
-// returns +1 if x is zero
-static SkScalar SkScalarSign(SkScalar x) {
+// returns +1 if z is zero
+static SkScalar SkScalarSignNonZero(SkScalar x) {
     SkScalar sign = SK_Scalar1;
     if (x < 0) {
         sign = -sign;
@@ -41,9 +41,9 @@ static void unit_axis_align(SkVector* unit) {
     const SkScalar TOLERANCE = SkDoubleToScalar(0.15);
     if (SkScalarAbs(unit->fX) < TOLERANCE) {
         unit->fX = 0;
-        unit->fY = SkScalarSign(unit->fY);
+        unit->fY = SkScalarSignNonZero(unit->fY);
     } else if (SkScalarAbs(unit->fY) < TOLERANCE) {
-        unit->fX = SkScalarSign(unit->fX);
+        unit->fX = SkScalarSignNonZero(unit->fX);
         unit->fY = 0;
     }
 }