cc/animation/transform_operations.h

   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 false if the operations affect 2d axis alignment.
  67   bool PreservesAxisAlignment() const;
  68
  69   // Returns true if this operation and its descendants have the same types
  70   // as other and its descendants.
  71   bool MatchesTypes(const TransformOperations& other) const;
  72
  73   // Returns true if these operations can be blended. It will only return
  74   // false if we must resort to matrix interpolation, and matrix interpolation
  75   // fails (this can happen if either matrix cannot be decomposed).
  76   bool CanBlendWith(const TransformOperations& other) const;
  77
  78   // If these operations have no more than one scale operation, and if the only
  79   // other operations are translations, sets |scale| to the scale component
  80   // of these operations. Otherwise, returns false.
  81   bool ScaleComponent(gfx::Vector3dF* scale) const;
  82
  83   void AppendTranslate(SkMScalar x, SkMScalar y, SkMScalar z);
  84   void AppendRotate(SkMScalar x, SkMScalar y, SkMScalar z, SkMScalar degrees);
  85   void AppendScale(SkMScalar x, SkMScalar y, SkMScalar z);
  86   void AppendSkew(SkMScalar x, SkMScalar y);
  87   void AppendPerspective(SkMScalar depth);
  88   void AppendMatrix(const gfx::Transform& matrix);
  89   void AppendIdentity();
  90   bool IsIdentity() const;
  91
  92  private:
  93   bool BlendInternal(const TransformOperations& from,
  94                      SkMScalar progress,
  95                      gfx::Transform* result) const;
  96
  97   std::vector<TransformOperation> operations_;
  98
  99   bool ComputeDecomposedTransform() const;
 100
 101   // For efficiency, we cache the decomposed transform.
 102   mutable scoped_ptr<gfx::DecomposedTransform> decomposed_transform_;
 103   mutable bool decomposed_transform_dirty_;
 104
 105   DISALLOW_ASSIGN(TransformOperations);
 106 };
 107
 108 }  // namespace cc
 109
 110 #endif  // CC_ANIMATION_TRANSFORM_OPERATIONS_H_