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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CC_ANIMATION_TRANSFORM_OPERATIONS_H_
      6 #define CC_ANIMATION_TRANSFORM_OPERATIONS_H_
      7 
      8 #include <vector>
      9 
     10 #include "base/memory/scoped_ptr.h"
     11 #include "cc/animation/transform_operation.h"
     12 #include "cc/base/cc_export.h"
     13 #include "ui/gfx/transform.h"
     14 
     15 namespace gfx {
     16 class BoxF;
     17 struct DecomposedTransform;
     18 }
     19 
     20 namespace cc {
     21 
     22 // Transform operations are a decomposed transformation matrix. It can be
     23 // applied to obtain a gfx::Transform at any time, and can be blended
     24 // intelligently with other transform operations, so long as they represent the
     25 // same decomposition. For example, if we have a transform that is made up of
     26 // a rotation followed by skew, it can be blended intelligently with another
     27 // transform made up of a rotation followed by a skew. Blending is possible if
     28 // we have two dissimilar sets of transform operations, but the effect may not
     29 // be what was intended. For more information, see the comments for the blend
     30 // function below.
     31 class CC_EXPORT TransformOperations {
     32  public:
     33   TransformOperations();
     34   TransformOperations(const TransformOperations& other);
     35   ~TransformOperations();
     36 
     37   // Returns a transformation matrix representing these transform operations.
     38   gfx::Transform Apply() const;
     39 
     40   // Given another set of transform operations and a progress in the range
     41   // [0, 1], returns a transformation matrix representing the intermediate
     42   // value. If this->MatchesTypes(from), then each of the operations are
     43   // blended separately and then combined. Otherwise, the two sets of
     44   // transforms are baked to matrices (using apply), and the matrices are
     45   // then decomposed and interpolated. For more information, see
     46   // http://www.w3.org/TR/2011/WD-css3-2d-transforms-20111215/#matrix-decomposition.
     47   gfx::Transform Blend(const TransformOperations& from,
     48                        SkMScalar progress) const;
     49 
     50   // Sets |bounds| be the bounding box for the region within which |box| will
     51   // exist when it is transformed by the result of calling Blend on |from| and
     52   // with progress in the range [min_progress, max_progress]. If this region
     53   // cannot be computed, returns false.
     54   bool BlendedBoundsForBox(const gfx::BoxF& box,
     55                            const TransformOperations& from,
     56                            SkMScalar min_progress,
     57                            SkMScalar max_progress,
     58                            gfx::BoxF* bounds) const;
     59 
     60   // Returns true if these operations affect scale.
     61   bool AffectsScale() const;
     62 
     63   // Returns true if these operations are only translations.
     64   bool IsTranslation() const;
     65 
     66   // Returns true if this operation and its descendants have the same types
     67   // as other and its descendants.
     68   bool MatchesTypes(const TransformOperations& other) const;
     69 
     70   // Returns true if these operations can be blended. It will only return
     71   // false if we must resort to matrix interpolation, and matrix interpolation
     72   // fails (this can happen if either matrix cannot be decomposed).
     73   bool CanBlendWith(const TransformOperations& other) const;
     74 
     75   // If these operations have no more than one scale operation, and if the only
     76   // other operations are translations, sets |scale| to the scale component
     77   // of these operations. Otherwise, returns false.
     78   bool ScaleComponent(gfx::Vector3dF* scale) const;
     79 
     80   void AppendTranslate(SkMScalar x, SkMScalar y, SkMScalar z);
     81   void AppendRotate(SkMScalar x, SkMScalar y, SkMScalar z, SkMScalar degrees);
     82   void AppendScale(SkMScalar x, SkMScalar y, SkMScalar z);
     83   void AppendSkew(SkMScalar x, SkMScalar y);
     84   void AppendPerspective(SkMScalar depth);
     85   void AppendMatrix(const gfx::Transform& matrix);
     86   void AppendIdentity();
     87   bool IsIdentity() const;
     88 
     89  private:
     90   bool BlendInternal(const TransformOperations& from,
     91                      SkMScalar progress,
     92                      gfx::Transform* result) const;
     93 
     94   std::vector<TransformOperation> operations_;
     95 
     96   bool ComputeDecomposedTransform() const;
     97 
     98   // For efficiency, we cache the decomposed transform.
     99   mutable scoped_ptr<gfx::DecomposedTransform> decomposed_transform_;
    100   mutable bool decomposed_transform_dirty_;
    101 
    102   DISALLOW_ASSIGN(TransformOperations);
    103 };
    104 
    105 }  // namespace cc
    106 
    107 #endif  // CC_ANIMATION_TRANSFORM_OPERATIONS_H_
    108