Upstream ios/web/navigation

ios/web/public/web_state/page_scroll_state.h

+// Copyright 2015 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.
+
+#ifndef IOS_WEB_PUBLIC_WEB_STATE_PAGE_SCROLL_STATE_H_
+#define IOS_WEB_PUBLIC_WEB_STATE_PAGE_SCROLL_STATE_H_
+
+namespace web {
+
+// Class used to represent the scrolling offset and the zoom scale of a webview.
+class PageScrollState {
+ public:
+  // Default constructor.  Initializes scroll offsets and zoom scales to NAN.
+  PageScrollState();
+  // Constructor with initial values.
+  PageScrollState(double scroll_offset_x,
+                  double scroll_offset_y,
+                  double minimum_zoom_scale,
+                  double maximum_zoom_scale,
+                  double zoom_scale);
+  ~PageScrollState();
+
+  // PageScrollStates cannot be applied until the scroll offset and zoom scale
+  // are both valid.
+  bool IsValid() const;
+
+  // The scroll offset is valid if its x and y values are both non-NAN.
+  bool IsScrollOffsetValid() const;
+
+  // Non-legacy zoom scales are valid if all three values are non-NAN and the
+  // zoom scale is within the minimum and maximum scales.  Legacy-format
+  // PageScrollStates are considered valid if the minimum and maximum scales
+  // are NAN and the zoom scale is greater than zero.
+  bool IsZoomScaleValid() const;
+
+  // PageScrollStates restored from the legacy serialization format make
+  // assumptions about the web view's implementation of zooming, and contain a
+  // non-NAN zoom scale and a NAN minimum and maximum scale.  Legacy zoom scales
+  // can only be applied to CRWUIWebViewWebControllers.
+  bool IsZoomScaleLegacyFormat() const;
+
+  // Accessors for scroll offsets and zoom scale.
+  double scroll_offset_x() const { return scroll_offset_x_; }
+  void set_scroll_offset_x(double scroll_offset_x) {
+    scroll_offset_x_ = scroll_offset_x;
+  }
+  double scroll_offset_y() const { return scroll_offset_y_; }
+  void set_scroll_offset_y(double scroll_offset_y) {
+    scroll_offset_y_ = scroll_offset_y;
+  }
+  double minimum_zoom_scale() const { return minimum_zoom_scale_; }
+  void set_minimum_zoom_scale(double minimum_zoom_scale) {
+    minimum_zoom_scale_ = minimum_zoom_scale;
+  }
+  double maximum_zoom_scale() const { return maximum_zoom_scale_; }
+  void set_maximum_zoom_scale(double maximum_zoom_scale) {
+    maximum_zoom_scale_ = maximum_zoom_scale;
+  }
+  double zoom_scale() const { return zoom_scale_; }
+  void set_zoom_scale(double zoom_scale) { zoom_scale_ = zoom_scale; }
+
+  // Comparator operator.
+  bool operator==(const PageScrollState& other) const;
+
+ private:
+  double scroll_offset_x_;
+  double scroll_offset_y_;
+  double minimum_zoom_scale_;
+  double maximum_zoom_scale_;
+  double zoom_scale_;
+};
+
+}  // namespace web
+
+#endif  // IOS_WEB_PUBLIC_WEB_STATE_PAGE_SCROLL_STATE_H_