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_H_ 6 #define UI_GFX_TRANSFORM_H_ 7 8 #include <string> 9 10 #include "base/compiler_specific.h" 11 #include "third_party/skia/include/utils/SkMatrix44.h" 12 #include "ui/base/ui_export.h" 13 14 namespace gfx { 15 16 class RectF; 17 class Point; 18 class Point3F; 19 class Vector3dF; 20 21 // 4x4 transformation matrix. Transform is cheap and explicitly allows 22 // copy/assign. 23 class UI_EXPORT Transform { 24 public: 25 26 enum SkipInitialization { 27 kSkipInitialization 28 }; 29 30 Transform() : matrix_(SkMatrix44::kIdentity_Constructor) {} 31 32 // Skips initializing this matrix to avoid overhead, when we know it will be 33 // initialized before use. 34 Transform(SkipInitialization) 35 : matrix_(SkMatrix44::kUninitialized_Constructor) {} 36 Transform(const Transform& rhs) : matrix_(rhs.matrix_) {} 37 // Initialize with the concatenation of lhs * rhs. 38 Transform(const Transform& lhs, const Transform& rhs) 39 : matrix_(lhs.matrix_, rhs.matrix_) {} 40 // Constructs a transform from explicit 16 matrix elements. Elements 41 // should be given in row-major order. 42 Transform(double col1row1, double col2row1, double col3row1, double col4row1, 43 double col1row2, double col2row2, double col3row2, double col4row2, 44 double col1row3, double col2row3, double col3row3, double col4row3, 45 double col1row4, double col2row4, double col3row4, double col4row4); 46 // Constructs a transform from explicit 2d elements. All other matrix 47 // elements remain the same as the corresponding elements of an identity 48 // matrix. 49 Transform(double col1row1, double col2row1, 50 double col1row2, double col2row2, 51 double x_translation, double y_translation); 52 ~Transform() {} 53 54 bool operator==(const Transform& rhs) const { return matrix_ == rhs.matrix_; } 55 bool operator!=(const Transform& rhs) const { return matrix_ != rhs.matrix_; } 56 57 // Resets this transform to the identity transform. 58 void MakeIdentity() { matrix_.setIdentity(); } 59 60 // Applies the current transformation on a 2d rotation and assigns the result 61 // to |this|. 62 void Rotate(double degrees) { RotateAboutZAxis(degrees); } 63 64 // Applies the current transformation on an axis-angle rotation and assigns 65 // the result to |this|. 66 void RotateAboutXAxis(double degrees); 67 void RotateAboutYAxis(double degrees); 68 void RotateAboutZAxis(double degrees); 69 void RotateAbout(const Vector3dF& axis, double degrees); 70 71 // Applies the current transformation on a scaling and assigns the result 72 // to |this|. 73 void Scale(double x, double y); 74 void Scale3d(double x, double y, double z); 75 76 // Applies the current transformation on a translation and assigns the result 77 // to |this|. 78 void Translate(double x, double y); 79 void Translate3d(double x, double y, double z); 80 81 // Applies the current transformation on a skew and assigns the result 82 // to |this|. 83 void SkewX(double angle_x); 84 void SkewY(double angle_y); 85 86 // Applies the current transformation on a perspective transform and assigns 87 // the result to |this|. 88 void ApplyPerspectiveDepth(double depth); 89 90 // Applies a transformation on the current transformation 91 // (i.e. 'this = this * transform;'). 92 void PreconcatTransform(const Transform& transform); 93 94 // Applies a transformation on the current transformation 95 // (i.e. 'this = transform * this;'). 96 void ConcatTransform(const Transform& transform); 97 98 // Returns true if this is the identity matrix. 99 bool IsIdentity() const { return matrix_.isIdentity(); } 100 101 // Returns true if the matrix is either identity or pure translation. 102 bool IsIdentityOrTranslation() const { 103 return !(matrix_.getType() & ~SkMatrix44::kTranslate_Mask); 104 } 105 106 // Returns true if the matrix is either a positive scale and/or a translation. 107 bool IsPositiveScaleOrTranslation() const { 108 if (!IsScaleOrTranslation()) 109 return false; 110 return matrix_.getDouble(0, 0) > 0.0 && 111 matrix_.getDouble(1, 1) > 0.0 && 112 matrix_.getDouble(2, 2) > 0.0; 113 } 114 115 // Returns true if the matrix is either identity or pure, non-fractional 116 // translation. 117 bool IsIdentityOrIntegerTranslation() const; 118 119 // Returns true if the matrix is has only scaling and translation components. 120 bool IsScaleOrTranslation() const { 121 int mask = SkMatrix44::kScale_Mask | SkMatrix44::kTranslate_Mask; 122 return (matrix_.getType() & ~mask) == 0; 123 } 124 125 // Returns true if axis-aligned 2d rects will remain axis-aligned after being 126 // transformed by this matrix. 127 bool Preserves2dAxisAlignment() const; 128 129 // Returns true if the matrix has any perspective component that would 130 // change the w-component of a homogeneous point. 131 bool HasPerspective() const { 132 return (matrix_.getType() & SkMatrix44::kPerspective_Mask) != 0; 133 } 134 135 // Returns true if this transform is non-singular. 136 bool IsInvertible() const { return matrix_.invert(NULL); } 137 138 // Returns true if a layer with a forward-facing normal of (0, 0, 1) would 139 // have its back side facing frontwards after applying the transform. 140 bool IsBackFaceVisible() const; 141 142 // Inverts the transform which is passed in. Returns true if successful. 143 bool GetInverse(Transform* transform) const WARN_UNUSED_RESULT; 144 145 // Transposes this transform in place. 146 void Transpose(); 147 148 // Set 3rd row and 3rd colum to (0, 0, 1, 0). Note that this flattening 149 // operation is not quite the same as an orthographic projection and is 150 // technically not a linear operation. 151 // 152 // One useful interpretation of doing this operation: 153 // - For x and y values, the new transform behaves effectively like an 154 // orthographic projection was added to the matrix sequence. 155 // - For z values, the new transform overrides any effect that the transform 156 // had on z, and instead it preserves the z value for any points that are 157 // transformed. 158 // - Because of linearity of transforms, this flattened transform also 159 // preserves the effect that any subsequent (multiplied from the right) 160 // transforms would have on z values. 161 // 162 void FlattenTo2d(); 163 164 // Applies the transformation on the point. Returns true if the point is 165 // transformed successfully. 166 void TransformPoint(Point3F& point) const; 167 168 // Applies the transformation on the point. Returns true if the point is 169 // transformed successfully. Rounds the result to the nearest point. 170 void TransformPoint(Point& point) const; 171 172 // Applies the reverse transformation on the point. Returns true if the 173 // transformation can be inverted. 174 bool TransformPointReverse(Point3F& point) const; 175 176 // Applies the reverse transformation on the point. Returns true if the 177 // transformation can be inverted. Rounds the result to the nearest point. 178 bool TransformPointReverse(Point& point) const; 179 180 // Applies transformation on the rectangle. Returns true if the transformed 181 // rectangle was axis aligned. If it returns false, rect will be the 182 // smallest axis aligned bounding box containing the transformed rect. 183 void TransformRect(RectF* rect) const; 184 185 // Applies the reverse transformation on the rectangle. Returns true if 186 // the transformed rectangle was axis aligned. If it returns false, 187 // rect will be the smallest axis aligned bounding box containing the 188 // transformed rect. 189 bool TransformRectReverse(RectF* rect) const; 190 191 // Decomposes |this| and |from|, interpolates the decomposed values, and 192 // sets |this| to the reconstituted result. Returns false if either matrix 193 // can't be decomposed. Uses routines described in this spec: 194 // http://www.w3.org/TR/css3-3d-transforms/. 195 // 196 // Note: this call is expensive since we need to decompose the transform. If 197 // you're going to be calling this rapidly (e.g., in an animation) you should 198 // decompose once using gfx::DecomposeTransforms and reuse your 199 // DecomposedTransform. 200 bool Blend(const Transform& from, double progress); 201 202 // Returns |this| * |other|. 203 Transform operator*(const Transform& other) const { 204 return Transform(*this, other); 205 } 206 207 // Sets |this| = |this| * |other| 208 Transform& operator*=(const Transform& other) { 209 PreconcatTransform(other); 210 return *this; 211 } 212 213 // Returns the underlying matrix. 214 const SkMatrix44& matrix() const { return matrix_; } 215 SkMatrix44& matrix() { return matrix_; } 216 217 std::string ToString() const; 218 219 private: 220 void TransformPointInternal(const SkMatrix44& xform, 221 Point& point) const; 222 223 void TransformPointInternal(const SkMatrix44& xform, 224 Point3F& point) const; 225 226 SkMatrix44 matrix_; 227 228 // copy/assign are allowed. 229 }; 230 231 } // namespace gfx 232 233 #endif // UI_GFX_TRANSFORM_H_ 234
