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/point.h"
  10 #include "ui/gfx/transform.h"
  11
  12 namespace gfx {
  13
  14 class Point;
  15 class Rect;
  16
  17 // Returns a scale transform at |anchor| point.
  18 GFX_EXPORT Transform GetScaleTransform(const Point& anchor, float scale);
  19
  20 // Contains the components of a factored transform. These components may be
  21 // blended and recomposed.
  22 struct GFX_EXPORT DecomposedTransform {
  23   // The default constructor initializes the components in such a way that
  24   // if used with Compose below, will produce the identity transform.
  25   DecomposedTransform();
  26
  27   SkMScalar translate[3];
  28   SkMScalar scale[3];
  29   SkMScalar skew[3];
  30   SkMScalar perspective[4];
  31   SkMScalar quaternion[4];
  32
  33   std::string ToString() const;
  34
  35   // Copy and assign are allowed.
  36 };
  37
  38 // Interpolates the decomposed components |to| with |from| using the
  39 // routines described in http://www.w3.org/TR/css3-3d-transform/.
  40 // |progress| is in the range [0, 1] (0 leaves |out| unchanged, and 1
  41 // assigns |from| to |out|).
  42 GFX_EXPORT bool BlendDecomposedTransforms(DecomposedTransform* out,
  43                                           const DecomposedTransform& to,
  44                                           const DecomposedTransform& from,
  45                                           double progress);
  46
  47 // Decomposes this transform into its translation, scale, skew, perspective,
  48 // and rotation components following the routines detailed in this spec:
  49 // http://www.w3.org/TR/css3-3d-transforms/.
  50 GFX_EXPORT bool DecomposeTransform(DecomposedTransform* out,
  51                                    const Transform& transform);
  52
  53 // Composes a transform from the given translation, scale, skew, prespective,
  54 // and rotation components following the routines detailed in this spec:
  55 // http://www.w3.org/TR/css3-3d-transforms/.
  56 GFX_EXPORT Transform ComposeTransform(const DecomposedTransform& decomp);
  57
  58 GFX_EXPORT bool SnapTransform(Transform* out,
  59                               const Transform& transform,
  60                               const Rect& viewport);
  61
  62 // Calculates a transform with a transformed origin. The resulting tranform is
  63 // created by composing P * T * P^-1 where P is a constant transform to the new
  64 // origin.
  65 GFX_EXPORT Transform TransformAboutPivot(const gfx::Point& pivot,
  66                                          const gfx::Transform& transform);
  67
  68 }  // namespace gfx
  69
  70 #endif  // UI_GFX_TRANSFORM_UTIL_H_