Add a map homogenous points to SkMatrix

include/core/SkMatrix.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkMatrix_DEFINED
@@ skipping 405 matching lines @@
                              size_t stride, int count) const {
         SkASSERT(stride >= sizeof(SkPoint));
         SkASSERT(0 == stride % sizeof(SkScalar));
         for (int i = 0; i < count; ++i) {
             this->mapPoints(dst, src, 1);
             src = (SkPoint*)((intptr_t)src + stride);
             dst = (SkPoint*)((intptr_t)dst + stride);
         }
     }
 
+    /** Apply this matrix to the array of homogeneous points, specified by src,
+        where a homogeneous point is defined by 3 contiguous scalar values,
+        and write the transformed points into the array of scalars specified by dst.
+        dst[] = M * src[]
+        @param dst  Where the transformed coordinates are written. It must
+                    contain at least 3 * count entries
+        @param src  The original coordinates that are to be transformed. It
+                    must contain at least 3 * count entries
+        @param count The number of points in src to read, and then transform

[reed1, 2013/08/07 18:16:50]

Lets be very clear what 'count' is measuring. Its is the number of
homogeneous_points, not SkPoints. Maybe the dox could say the number of triples?
Perhaps a tiny argument for declaring a struct here, so that count would be
unambiguous (tho I don't know what to call it).

+                     into dst.
+    */
+    void mapHomogeneousPoints(SkScalar dst[], const SkScalar src[], int count) const;
+
     void mapXY(SkScalar x, SkScalar y, SkPoint* result) const {
         SkASSERT(result);
         this->getMapXYProc()(*this, x, y, result);
     }
 
     /** Apply this matrix to the array of vectors specified by src, and write
         the transformed vectors into the array of vectors specified by dst.
         This is similar to mapPoints, but ignores any translation in the matrix.
         @param dst  Where the transformed coordinates are written. It must
                     contain at least count entries
@@ skipping 223 matching lines @@
     static void Identity_pts(const SkMatrix&, SkPoint[], const SkPoint[], int);
     static void Trans_pts(const SkMatrix&, SkPoint dst[], const SkPoint[], int);
     static void Scale_pts(const SkMatrix&, SkPoint dst[], const SkPoint[], int);
     static void ScaleTrans_pts(const SkMatrix&, SkPoint dst[], const SkPoint[],
                                int count);
     static void Rot_pts(const SkMatrix&, SkPoint dst[], const SkPoint[], int);
     static void RotTrans_pts(const SkMatrix&, SkPoint dst[], const SkPoint[],
                              int count);
     static void Persp_pts(const SkMatrix&, SkPoint dst[], const SkPoint[], int);
 
+    static void Homogeneous_pts(const SkMatrix&, SkScalar dst[], const SkScalar[], int);

[reed1, 2013/08/07 18:16:50]

Why is there a separate static function? Can just put its impl inside the
method.

+
     static const MapPtsProc gMapPtsProcs[];
 
     friend class SkPerspIter;
 };
 
 #endif