Line data    Source code

       1             : /*
       2             :  * Copyright 2015 Google Inc.
       3             :  *
       4             :  * Use of this source code is governed by a BSD-style license that can be
       5             :  * found in the LICENSE file.
       6             :  */
       7             : 
       8             : #ifndef SkRSXform_DEFINED
       9             : #define SkRSXform_DEFINED
      10             : 
      11             : #include "SkPoint.h"
      12             : #include "SkSize.h"
      13             : 
      14             : /**
      15             :  *  A compressed form of a rotation+scale matrix.
      16             :  *
      17             :  *  [ fSCos     -fSSin    fTx ]
      18             :  *  [ fSSin      fSCos    fTy ]
      19             :  *  [     0          0      1 ]
      20             :  */
      21             : struct SkRSXform {
      22           0 :     static SkRSXform Make(SkScalar scos, SkScalar ssin, SkScalar tx, SkScalar ty) {
      23           0 :         SkRSXform xform = { scos, ssin, tx, ty };
      24           0 :         return xform;
      25             :     }
      26             : 
      27             :     /*
      28             :      *  Initialize a new xform based on the scale, rotation (in radians), final tx,ty location
      29             :      *  and anchor-point ax,ay within the src quad.
      30             :      *
      31             :      *  Note: the anchor point is not normalized (e.g. 0...1) but is in pixels of the src image.
      32             :      */
      33           0 :     static SkRSXform MakeFromRadians(SkScalar scale, SkScalar radians, SkScalar tx, SkScalar ty,
      34             :                                      SkScalar ax, SkScalar ay) {
      35           0 :         const SkScalar s = SkScalarSin(radians) * scale;
      36           0 :         const SkScalar c = SkScalarCos(radians) * scale;
      37           0 :         return Make(c, s, tx + -c * ax + s * ay, ty + -s * ax - c * ay);
      38             :     }
      39             : 
      40             :     SkScalar fSCos;
      41             :     SkScalar fSSin;
      42             :     SkScalar fTx;
      43             :     SkScalar fTy;
      44             : 
      45             :     bool rectStaysRect() const {
      46             :         return 0 == fSCos || 0 == fSSin;
      47             :     }
      48             :     
      49             :     void setIdentity() {
      50             :         fSCos = 1;
      51             :         fSSin = fTx = fTy = 0;
      52             :     }
      53             : 
      54             :     void set(SkScalar scos, SkScalar ssin, SkScalar tx, SkScalar ty) {
      55             :         fSCos = scos;
      56             :         fSSin = ssin;
      57             :         fTx = tx;
      58             :         fTy = ty;
      59             :     }
      60             : 
      61             :     void toQuad(SkScalar width, SkScalar height, SkPoint quad[4]) const;
      62             :     void toQuad(const SkSize& size, SkPoint quad[4]) const {
      63             :         this->toQuad(size.width(), size.height(), quad);
      64             :     }
      65             : };
      66             : 
      67             : #endif
      68             :