ui/gfx/transform_util.h

   1 // Copyright (c) 2012 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 UI_GFX_TRANSFORM_UTIL_H_
   6 #define UI_GFX_TRANSFORM_UTIL_H_
   7
   8 #include "ui/gfx/gfx_export.h"
   9 #include "ui/gfx/transform.h"
  10
  11 namespace gfx {
  12
  13 class Point;
  14 class Rect;
  15
  16 // Returns a scale transform at |anchor| point.
  17 GFX_EXPORT Transform GetScaleTransform(const Point& anchor, float scale);
  18
  19 // Contains the components of a factored transform. These components may be
  20 // blended and recomposed.
  21 struct GFX_EXPORT DecomposedTransform {
  22   // The default constructor initializes the components in such a way that
  23   // if used with Compose below, will produce the identity transform.
  24   DecomposedTransform();
  25
  26   SkMScalar translate[3];
  27   SkMScalar scale[3];
  28   SkMScalar skew[3];
  29   SkMScalar perspective[4];
  30   SkMScalar quaternion[4];
  31
  32   std::string ToString() const;
  33
  34   // Copy and assign are allowed.
  35 };
  36
  37 // Interpolates the decomposed components |to| with |from| using the
  38 // routines described in http://www.w3.org/TR/css3-3d-transform/.
  39 // |progress| is in the range [0, 1] (0 leaves |out| unchanged, and 1
  40 // assigns |from| to |out|).
  41 GFX_EXPORT bool BlendDecomposedTransforms(DecomposedTransform* out,
  42                                           const DecomposedTransform& to,
  43                                           const DecomposedTransform& from,
  44                                           double progress);
  45
  46 // Decomposes this transform into its translation, scale, skew, perspective,
  47 // and rotation components following the routines detailed in this spec:
  48 // http://www.w3.org/TR/css3-3d-transforms/.
  49 GFX_EXPORT bool DecomposeTransform(DecomposedTransform* out,
  50                                    const Transform& transform);
  51
  52 // Composes a transform from the given translation, scale, skew, prespective,
  53 // and rotation components following the routines detailed in this spec:
  54 // http://www.w3.org/TR/css3-3d-transforms/.
  55 GFX_EXPORT Transform ComposeTransform(const DecomposedTransform& decomp);
  56
  57 GFX_EXPORT bool SnapTransform(Transform* out,
  58                               const Transform& transform,
  59                               const Rect& viewport);
  60
  61 }  // namespace gfx
  62
  63 #endif  // UI_GFX_TRANSFORM_UTIL_H_