1 files changed, 110 insertions, 0 deletions
diff --git a/include/cru/platform/Matrix.h b/include/cru/platform/Matrix.h
new file mode 100644
index 00000000..c9a52158
--- /dev/null
+++ b/include/cru/platform/Matrix.h
@@ -0,0 +1,110 @@
+#pragma once
+#include "GraphicsBase.h"
+
+#include <cmath>
+#include <optional>
+
+namespace cru::platform {
+struct Matrix {
+  float m11;
+  float m12;
+  float m21;
+  float m22;
+  float m31;
+  float m32;
+
+  Matrix() {}
+
+  Matrix(float m11, float m12, float m21, float m22, float m31, float m32) {
+    this->m11 = m11;
+    this->m12 = m12;
+    this->m21 = m21;
+    this->m22 = m22;
+    this->m31 = m31;
+    this->m32 = m32;
+  }
+
+  bool IsIdentity() const {
+    return m11 == 1.0f && m12 == 0.0f && m21 == 0.0f && m22 == 1.0f &&
+           m31 == 0.0f && m32 == 0.0f;
+  }
+
+  Matrix& operator*=(const Matrix& matrix) {
+    *this = Product(*this, matrix);
+    return *this;
+  }
+
+  Matrix operator*(const Matrix& matrix) const {
+    return Product(*this, matrix);
+  }
+
+  Point TransformPoint(const Point& point) const {
+    return Point{point.x * m11 + point.y * m21 + m31,
+                 point.x * m12 + point.y * m22 + m32};
+  }
+
+  Rect TransformRect(const Rect& rect, bool normalize = true) const {
+    Point lefttop = TransformPoint(rect.GetLeftTop()),
+          rightbottom = TransformPoint(rect.GetRightBottom());
+    auto result =
+        Rect::FromVertices(lefttop.x, lefttop.y, rightbottom.x, rightbottom.y);
+    if (normalize) result = result.Normalize();
+    return result;
+  }
+
+  static Matrix Identity() {
+    return Matrix{1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f};
+  }
+
+  static Matrix Translation(float x, float y) {
+    return Matrix{1.0f, 0.0f, 0.0f, 1.0f, x, y};
+  }
+
+  static Matrix Translation(const Point& point) {
+    return Translation(point.x, point.y);
+  }
+
+  static Matrix Scale(float sx, float sy) {
+    return Matrix{sx, 0.0f, 0.0f, sy, 0.0f, 0.0f};
+  }
+
+  // Clockwise.
+  static Matrix Rotation(float angle) {
+    float r = AngleToRadian(angle);
+    float s = std::sin(r);
+    float c = std::cos(r);
+
+    return Matrix{c, s, -s, c, 0.0f, 0.0f};
+  }
+
+  static Matrix Skew(float sx, float sy) {
+    return Matrix{1.0f, sx, sy, 1.0f, 0.0f, 0.0f};
+  }
+
+  static Matrix Product(const Matrix& a, const Matrix& b) {
+    return Matrix{a.m11 * b.m11 + a.m12 * b.m21,
+                  a.m11 * b.m12 + a.m12 * b.m22,
+                  a.m21 * b.m11 + a.m22 * b.m21,
+                  a.m21 * b.m12 + a.m22 * b.m22,
+                  a.m31 * b.m11 + a.m32 * b.m21 + b.m31,
+                  a.m31 * b.m12 + a.m32 * b.m22 + b.m32};
+  }
+
+  std::optional<Matrix> Inverted() const {
+    if (m11 * m22 == m12 * m21) return std::nullopt;
+    Matrix result;
+    result.m11 = m22 / (m11 * m22 - m12 * m21);
+    result.m12 = m12 / (m12 * m21 - m11 * m22);
+    result.m21 = m21 / (m12 * m21 - m11 * m22);
+    result.m22 = m11 / (m11 * m22 - m12 * m21);
+    result.m31 = (m21 * m32 - m22 * m31) / (m11 * m22 - m12 * m21);
+    result.m32 = (m31 * m12 - m11 * m32) / (m11 * m22 - m12 * m21);
+    return result;
+  }
+
+ private:
+  static constexpr float PI = 3.1415926535f;
+
+  static float AngleToRadian(float angle) { return angle / 180.f * PI; }
+};
+}  // namespace cru::platform