ios/web/public/web_state/page_scroll_state.h

   1 // Copyright 2015 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 IOS_WEB_PUBLIC_WEB_STATE_PAGE_SCROLL_STATE_H_
   6 #define IOS_WEB_PUBLIC_WEB_STATE_PAGE_SCROLL_STATE_H_
   7
   8 namespace web {
   9
  10 // Class used to represent the scrolling offset and the zoom scale of a webview.
  11 class PageScrollState {
  12  public:
  13   // Default constructor.  Initializes scroll offsets and zoom scales to NAN.
  14   PageScrollState();
  15   // Constructor with initial values.
  16   PageScrollState(double scroll_offset_x,
  17                   double scroll_offset_y,
  18                   double minimum_zoom_scale,
  19                   double maximum_zoom_scale,
  20                   double zoom_scale);
  21   ~PageScrollState();
  22
  23   // PageScrollStates cannot be applied until the scroll offset and zoom scale
  24   // are both valid.
  25   bool IsValid() const;
  26
  27   // The scroll offset is valid if its x and y values are both non-NAN.
  28   bool IsScrollOffsetValid() const;
  29
  30   // Non-legacy zoom scales are valid if all three values are non-NAN and the
  31   // zoom scale is within the minimum and maximum scales.  Legacy-format
  32   // PageScrollStates are considered valid if the minimum and maximum scales
  33   // are NAN and the zoom scale is greater than zero.
  34   bool IsZoomScaleValid() const;
  35
  36   // PageScrollStates restored from the legacy serialization format make
  37   // assumptions about the web view's implementation of zooming, and contain a
  38   // non-NAN zoom scale and a NAN minimum and maximum scale.  Legacy zoom scales
  39   // can only be applied to CRWUIWebViewWebControllers.
  40   bool IsZoomScaleLegacyFormat() const;
  41
  42   // Accessors for scroll offsets and zoom scale.
  43   double scroll_offset_x() const { return scroll_offset_x_; }
  44   void set_scroll_offset_x(double scroll_offset_x) {
  45     scroll_offset_x_ = scroll_offset_x;
  46   }
  47   double scroll_offset_y() const { return scroll_offset_y_; }
  48   void set_scroll_offset_y(double scroll_offset_y) {
  49     scroll_offset_y_ = scroll_offset_y;
  50   }
  51   double minimum_zoom_scale() const { return minimum_zoom_scale_; }
  52   void set_minimum_zoom_scale(double minimum_zoom_scale) {
  53     minimum_zoom_scale_ = minimum_zoom_scale;
  54   }
  55   double maximum_zoom_scale() const { return maximum_zoom_scale_; }
  56   void set_maximum_zoom_scale(double maximum_zoom_scale) {
  57     maximum_zoom_scale_ = maximum_zoom_scale;
  58   }
  59   double zoom_scale() const { return zoom_scale_; }
  60   void set_zoom_scale(double zoom_scale) { zoom_scale_ = zoom_scale; }
  61
  62   // Comparator operator.
  63   bool operator==(const PageScrollState& other) const;
  64
  65  private:
  66   double scroll_offset_x_;
  67   double scroll_offset_y_;
  68   double minimum_zoom_scale_;
  69   double maximum_zoom_scale_;
  70   double zoom_scale_;
  71 };
  72
  73 }  // namespace web
  74
  75 #endif  // IOS_WEB_PUBLIC_WEB_STATE_PAGE_SCROLL_STATE_H_