Add matrix constructing helpers 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
 #define SkMatrix_DEFINED
 
 #include "SkRect.h"
 
 class SkString;
 
 /** \class SkMatrix
 
     The SkMatrix class holds a 3x3 matrix for transforming coordinates.
     SkMatrix does not have a constructor, so it must be explicitly initialized
     using either reset() - to construct an identity matrix, or one of the set
     functions (e.g. setTranslate, setRotate, etc.).
 */
 class SK_API SkMatrix {
 public:
+    static SkMatrix SK_WARN_UNUSED_RESULT MakeScale(SkScalar sx, SkScalar sy) {
+        SkMatrix m;
+        m.setScale(sx, sy);
+        return m;
+    }
+
+    static SkMatrix SK_WARN_UNUSED_RESULT MakeTrans(SkScalar dx, SkScalar dy) {
+        SkMatrix m;
+        m.setTranslate(dx, dy);
+        return m;
+    }
+
     /** Enum of bit fields for the mask return by getType().
         Use this to identify the complexity of the matrix.
     */
     enum TypeMask {
         kIdentity_Mask      = 0,
         kTranslate_Mask     = 0x01,  //!< set if the matrix has translation
         kScale_Mask         = 0x02,  //!< set if the matrix has X or Y scale
         kAffine_Mask        = 0x04,  //!< set if the matrix skews or rotates
         kPerspective_Mask   = 0x08   //!< set if the matrix is in perspective
     };
@@ skipping 750 matching lines @@
     static void RotTrans_pts(const SkMatrix&, SkPoint dst[], const SkPoint[],
                              int count);
     static void Persp_pts(const SkMatrix&, SkPoint dst[], const SkPoint[], int);
 
     static const MapPtsProc gMapPtsProcs[];
 
     friend class SkPerspIter;
 };
 
 #endif