add SkPoint::CanNormalize to unify decisions about when a vector is degenerate

git-svn-id: http://skia.googlecode.com/svn/trunk@2236 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 12 insertions, 1 deletions

diff --git a/include/core/SkPoint.h b/include/core/SkPoint.h
index 7b9fdf99ca..8ba2cbcaa6 100644
--- a/include/core/SkPoint.h
+++ b/include/core/SkPoint.h
@@ -199,6 +199,16 @@ struct SK_API SkPoint {
     SkScalar length() const { return SkPoint::Length(fX, fY); }
     SkScalar distanceToOrigin() const { return this->length(); }
 
+    /**
+     *  Return true if the computed length of the vector is >= the internal
+     *  tolerance (used to avoid dividing by tiny values).
+     */
+    static bool CanNormalize(SkScalar dx, SkScalar dy);
+
+    bool canNormalize() const {
+        return CanNormalize(fX, fY);
+    }
+
     /** Set the point (vector) to be unit-length in the same direction as it
         already points.  If the point has a degenerate length (i.e. nearly 0)
         then return false and do nothing; otherwise return true.
@@ -317,7 +327,8 @@ struct SK_API SkPoint {
     static SkScalar Length(SkScalar x, SkScalar y);
 
     /** Normalize pt, returning its previous length. If the prev length is too
-        small (degenerate), return 0 and leave pt unchanged.
+        small (degenerate), return 0 and leave pt unchanged. This uses the same
+        tolerance as CanNormalize.
 
         Note that this method may be significantly more expensive than
         the non-static normalize(), because it has to return the previous length