[Remoting Client] DesktopViewport Implementation

remoting/client/view_matrix.cc

Index: remoting/client/view_matrix.cc
diff --git a/remoting/client/view_matrix.cc b/remoting/client/view_matrix.cc
new file mode 100644
index 0000000000000000000000000000000000000000..798548fcf4f2f27e82e87daeb7431327b1a5c59b
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+++ b/remoting/client/view_matrix.cc
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+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/client/view_matrix.h"
+
+namespace remoting {
+
+ViewMatrix::ViewMatrix() : ViewMatrix(0.f, {0.f, 0.f}) {}
+
+ViewMatrix::ViewMatrix(float scale, const Vector2D& offset)
+    : scale_(scale), offset_(offset) {}
+
+ViewMatrix::~ViewMatrix() {}
+
+ViewMatrix::Point ViewMatrix::MapPoint(const Point& point) const {
+  float x = scale_ * point.x + offset_.x;
+  float y = scale_ * point.y + offset_.y;
+  return {x, y};
+}
+
+ViewMatrix::Vector2D ViewMatrix::MapVector(const Vector2D& vector) const {
+  float x = scale_ * vector.x;
+  float y = scale_ * vector.y;
+  return {x, y};
+}
+
+void ViewMatrix::SetScale(float scale) {
+  scale_ = scale;
+}
+
+float ViewMatrix::GetScale() const {
+  return scale_;
+}
+
+void ViewMatrix::PostScale(const Point& pivot, float scale) {
+  scale_ *= scale;
+  offset_.x += (1.f - scale) * pivot.x;
+  offset_.y += (1.f - scale) * pivot.y;
+}
+
+void ViewMatrix::PostTranslate(const Vector2D& delta) {
+  offset_.x += delta.x;
+  offset_.y += delta.y;
+}
+
+ViewMatrix ViewMatrix::Invert() const {
+  return ViewMatrix(1.f / scale_, {-offset_.x / scale_, -offset_.y / scale_});
+}
+
+std::array<float, 9> ViewMatrix::ToMatrixArray() const {
+  return {{scale_, 0, offset_.x,  // Row 1
+           0, scale_, offset_.y,  // Row 2
+           0, 0, 1}};
+}
+
+bool ViewMatrix::IsEmpty() const {
+  return scale_ == 0.f && offset_.x == 0.f && offset_.y == 0.f;
+}
+
+}  // namespace remoting