third_party/WebKit/Source/core/dom/ViewportDescription.h

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2001 Dirk Mueller (mueller@kde.org)
 *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
 * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 * Copyright (C) 2008 Torch Mobile Inc. All rights reserved.
 * (http://www.torchmobile.com/)
 * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) 2012-2013 Intel Corporation. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef ViewportDescription_h
#define ViewportDescription_h

#include "core/CoreExport.h"
#include "core/frame/PageScaleConstraints.h"
#include "platform/Length.h"
#include "platform/geometry/FloatSize.h"
#include "wtf/Allocator.h"

namespace blink {

class LocalFrame;

struct CORE_EXPORT ViewportDescription {
  DISALLOW_NEW();

  enum Type {
    // These are ordered in increasing importance.
    UserAgentStyleSheet,
    HandheldFriendlyMeta,
    MobileOptimizedMeta,
    ViewportMeta,
    AuthorStyleSheet
  } type;

  enum {
    ValueAuto = -1,
    ValueDeviceWidth = -2,
    ValueDeviceHeight = -3,
    ValuePortrait = -4,
    ValueLandscape = -5,
    ValueDeviceDPI = -6,
    ValueLowDPI = -7,
    ValueMediumDPI = -8,
    ValueHighDPI = -9,
    ValueExtendToZoom = -10
  };

  ViewportDescription(Type type = UserAgentStyleSheet)
      : type(type),
        zoom(ValueAuto),
        minZoom(ValueAuto),
        maxZoom(ValueAuto),
        userZoom(true),
        orientation(ValueAuto),
        deprecatedTargetDensityDPI(ValueAuto),
        zoomIsExplicit(false),
        minZoomIsExplicit(false),
        maxZoomIsExplicit(false),
        userZoomIsExplicit(false) {}

  // All arguments are in CSS units.
  PageScaleConstraints resolve(const FloatSize& initialViewportSize,
                               Length legacyFallbackWidth) const;

  Length minWidth;
  Length maxWidth;
  Length minHeight;
  Length maxHeight;
  float zoom;
  float minZoom;
  float maxZoom;
  bool userZoom;
  float orientation;
  float deprecatedTargetDensityDPI;  // Only used for Android WebView

  // Whether the computed value was explicitly specified rather than being
  // inferred.
  bool zoomIsExplicit;
  bool minZoomIsExplicit;
  bool maxZoomIsExplicit;
  bool userZoomIsExplicit;

  bool operator==(const ViewportDescription& other) const {
    // Used for figuring out whether to reset the viewport or not,
    // thus we are not taking type into account.
    return minWidth == other.minWidth && maxWidth == other.maxWidth &&
           minHeight == other.minHeight && maxHeight == other.maxHeight &&
           zoom == other.zoom && minZoom == other.minZoom &&
           maxZoom == other.maxZoom && userZoom == other.userZoom &&
           orientation == other.orientation &&
           deprecatedTargetDensityDPI == other.deprecatedTargetDensityDPI &&
           zoomIsExplicit == other.zoomIsExplicit &&
           minZoomIsExplicit == other.minZoomIsExplicit &&
           maxZoomIsExplicit == other.maxZoomIsExplicit &&
           userZoomIsExplicit == other.userZoomIsExplicit;
  }

  bool operator!=(const ViewportDescription& other) const {
    return !(*this == other);
  }

  bool isLegacyViewportType() const {
    return type >= HandheldFriendlyMeta && type <= ViewportMeta;
  }
  bool isMetaViewportType() const { return type == ViewportMeta; }
  bool isSpecifiedByAuthor() const { return type != UserAgentStyleSheet; }
  bool matchesHeuristicsForGpuRasterization() const;

  // Reports UMA stat on whether the page is considered mobile or desktop and
  // what kind of mobile it is. Applies only to Android, must only be called
  // once per page load.
  void reportMobilePageStats(const LocalFrame*) const;

 private:
  enum Direction { Horizontal, Vertical };
  static float resolveViewportLength(const Length&,
                                     const FloatSize& initialViewportSize,
                                     Direction);
};

}  // namespace blink

#endif  // ViewportDescription_h