/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* Per-block-formatting-context manager of font size inflation for pan and zoom UI. */

#ifndef nsFontInflationData_h_

#define nsFontInflationData_h_

#include "nsContainerFrame.h"

class nsFontInflationData

{

  using ReflowInput = mozilla::ReflowInput;

public:

  static nsFontInflationData* FindFontInflationDataFor(const nsIFrame *aFrame);

  // Returns whether the effective width changed (which requires the

  // caller to mark its descendants dirty

  static bool

    UpdateFontInflationDataISizeFor(const ReflowInput& aReflowInput);

  static void MarkFontInflationDataTextDirty(nsIFrame *aFrame);

  bool InflationEnabled() {

    if (mTextDirty) {

      ScanText();

    }

    return mInflationEnabled;

  }

  nscoord EffectiveISize() const {

    return mNCAISize;

  }

private:

  explicit nsFontInflationData(nsIFrame* aBFCFrame);

  nsFontInflationData(const nsFontInflationData&) = delete;

  void operator=(const nsFontInflationData&) = delete;

  void UpdateISize(const ReflowInput &aReflowInput);

  enum SearchDirection { eFromStart, eFromEnd };

  static nsIFrame* FindEdgeInflatableFrameIn(nsIFrame *aFrame,

                                             SearchDirection aDirection);

  void MarkTextDirty() { mTextDirty = true; }

  void ScanText();

  // Scan text in the subtree rooted at aFrame.  Increment mTextAmount

  // by multiplying the number of characters found by the font size

  // (yielding the inline-size that would be occupied by the characters if

  // they were all em squares).  But stop scanning if mTextAmount

  // crosses mTextThreshold.

  void ScanTextIn(nsIFrame *aFrame);

  static const nsIFrame* FlowRootFor(const nsIFrame *aFrame)

  {

    while (!(aFrame->GetStateBits() & NS_FRAME_FONT_INFLATION_FLOW_ROOT)) {

      aFrame = aFrame->GetParent();

    }

    return aFrame;

  }

  nsIFrame *mBFCFrame;

  nscoord mNCAISize;

  nscoord mTextAmount, mTextThreshold;

  bool mInflationEnabled; // for this BFC

  bool mTextDirty;

};

#endif /* !defined(nsFontInflationData_h_) */