The Tor Browser: layout/generic/WritingModes.h@b8a032363ba2 (annotated)

layout/generic/WritingModes.h@b8a032363ba2 (annotated)

layout/generic/WritingModes.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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/. */
 #ifndef WritingModes_h_
 #define WritingModes_h_
 #include "nsRect.h"
 #include "nsStyleStruct.h"
 // If WRITING_MODE_VERTICAL_ENABLED is defined, we will attempt to support
 // the vertical writing-mode values; if it is not defined, then
 // WritingMode.IsVertical() will be hard-coded to return false, allowing
 // many conditional branches to be optimized away while we're in the process
 // of transitioning layout to use writing-mode and logical directions, but
 // not yet ready to ship vertical support.
 /* #define WRITING_MODE_VERTICAL_ENABLED 1 */
 // It is the caller's responsibility to operate on logical-coordinate objects
 // with matched writing modes. Failure to do so will be a runtime bug; the
 // compiler can't catch it, but in debug mode, we'll throw an assertion.
 // NOTE that in non-debug builds, a writing mode mismatch error will NOT be
 // detected, yet the results will be nonsense (and may lead to further layout
 // failures). Therefore, it is important to test (and fuzz-test) writing-mode
 // support using debug builds.
 // Methods in logical-coordinate classes that take another logical-coordinate
 // object as a parameter should call CHECK_WRITING_MODE on it to verify that
 // the writing modes match.
 // (In some cases, there are internal (private) methods that don't do this;
 // such methods should only be used by other methods that have already checked
 // the writing modes.)
 #define CHECK_WRITING_MODE(param) \
    NS_ASSERTION(param == mWritingMode, "writing-mode mismatch")
 /**
  * mozilla::WritingMode is an immutable class representing a
  * writing mode.
  *
  * It efficiently stores the writing mode and can rapidly compute
  * interesting things about it for use in layout.
  *
  * Writing modes are computed from the CSS 'direction',
  * 'writing-mode', and 'text-orientation' properties.
  * See CSS3 Writing Modes for more information
  *   http://www.w3.org/TR/css3-writing-modes/
  */
 namespace mozilla {
 class WritingMode {
 public:
   /**
    * Absolute inline flow direction
    */
   enum InlineDir {
     eInlineLTR = 0x00, // text flows horizontally left to right
     eInlineRTL = 0x02, // text flows horizontally right to left
     eInlineTTB = 0x01, // text flows vertically top to bottom
     eInlineBTT = 0x03, // text flows vertically bottom to top
   };
   /**
    * Absolute block flow direction
    */
   enum BlockDir {
     eBlockTB = 0x00, // horizontal lines stack top to bottom
     eBlockRL = 0x01, // vertical lines stack right to left
     eBlockLR = 0x05, // vertical lines stack left to right
   };
   /**
    * Line-relative (bidi-relative) inline flow direction
    */
   enum BidiDir {
     eBidiLTR = 0x00, // inline flow matches bidi LTR text
     eBidiRTL = 0x10, // inline flow matches bidi RTL text
   };
   /**
    * Unknown writing mode (should never actually be stored or used anywhere).
    */
   enum {
     eUnknownWritingMode = 0xff
   };
   /**
    * Return the absolute inline flow direction as an InlineDir
    */
   InlineDir GetInlineDir() const { return InlineDir(mWritingMode & eInlineMask); }
   /**
    * Return the absolute block flow direction as a BlockDir
    */
   BlockDir GetBlockDir() const { return BlockDir(mWritingMode & eBlockMask); }
   /**
    * Return the line-relative inline flow direction as a BidiDir
    */
   BidiDir GetBidiDir() const { return BidiDir(mWritingMode & eBidiMask); }
   /**
    * Return true if LTR. (Convenience method)
    */
   bool IsBidiLTR() const { return eBidiLTR == (mWritingMode & eBidiMask); }
   /**
    * True if vertical-mode block direction is LR (convenience method).
    */
   bool IsVerticalLR() const { return eBlockLR == (mWritingMode & eBlockMask); }
   /**
    * True if vertical writing mode, i.e. when
    * writing-mode: vertical-lr | vertical-rl.
    */
 #ifdef WRITING_MODE_VERTICAL_ENABLED
   bool IsVertical() const { return !!(mWritingMode & eOrientationMask); }
 #else
   bool IsVertical() const { return false; }
 #endif
   /**
    * True if line-over/line-under are inverted from block-start/block-end.
    * This is true when
    *   - writing-mode is vertical-rl && text-orientation is sideways-left
    *   - writing-mode is vertical-lr && text-orientation is not sideways-left
    */
 #ifdef WRITING_MODE_VERTICAL_ENABLED
   bool IsLineInverted() const { return !!(mWritingMode & eLineOrientMask); }
 #else
   bool IsLineInverted() const { return false; }
 #endif
   /**
    * Block-axis flow-relative to line-relative factor.
    * May be used as a multiplication factor for block-axis coordinates
    * to convert between flow- and line-relative coordinate systems (e.g.
    * positioning an over- or under-line decoration).
    */
   int FlowRelativeToLineRelativeFactor() const
   {
     return IsLineInverted() ? -1 : 1;
   }
   /**
    * Default constructor gives us a horizontal, LTR writing mode.
    * XXX We will probably eliminate this and require explicit initialization
    *     in all cases once transition is complete.
    */
   WritingMode()
     : mWritingMode(0)
   { }
   /**
    * Construct writing mode based on a style context
    */
   WritingMode(const nsStyleVisibility* aStyleVisibility)
   {
     NS_ASSERTION(aStyleVisibility, "we need an nsStyleVisibility here");
 #ifdef WRITING_MODE_VERTICAL_ENABLED
     switch (aStyleVisibility->mWritingMode) {
       case NS_STYLE_WRITING_MODE_HORIZONTAL_TB:
         mWritingMode = 0;
         break;
       case NS_STYLE_WRITING_MODE_VERTICAL_LR:
         mWritingMode = eBlockFlowMask |
                        eLineOrientMask | //XXX needs update when text-orientation added
                        eOrientationMask;
         break;
       case NS_STYLE_WRITING_MODE_VERTICAL_RL:
         mWritingMode = eOrientationMask;
         break;
       default:
         NS_NOTREACHED("unknown writing mode!");
         mWritingMode = 0;
         break;
     }
 #else
     mWritingMode = 0;
 #endif
     if (NS_STYLE_DIRECTION_RTL == aStyleVisibility->mDirection) {
       mWritingMode |= eInlineFlowMask | //XXX needs update when text-orientation added
                       eBidiMask;
     }
   }
   // For unicode-bidi: plaintext, reset the direction of the writing mode from
   // the bidi paragraph level of the content
   //XXX change uint8_t to UBiDiLevel after bug 924851
   void SetDirectionFromBidiLevel(uint8_t level)
   {
     if (level & 1) {
       // odd level, set RTL
       mWritingMode |= eBidiMask;
     } else {
       // even level, set LTR
       mWritingMode &= ~eBidiMask;
     }
   }
   /**
    * Compare two WritingModes for equality.
    */
   bool operator==(const WritingMode& aOther) const
   {
     return mWritingMode == aOther.mWritingMode;
   }
 private:
   friend class LogicalPoint;
   friend class LogicalSize;
   friend class LogicalMargin;
   friend class LogicalRect;
   /**
    * Return a WritingMode representing an unknown value.
    */
   static inline WritingMode Unknown()
   {
     return WritingMode(eUnknownWritingMode);
   }
   /**
    * Constructing a WritingMode with an arbitrary value is a private operation
    * currently only used by the Unknown() static method.
    */
   WritingMode(uint8_t aValue)
     : mWritingMode(aValue)
   { }
   uint8_t mWritingMode;
   enum Masks {
     // Masks for our bits; true chosen as opposite of commonest case
     eOrientationMask = 0x01, // true means vertical text
     eInlineFlowMask  = 0x02, // true means absolute RTL/BTT (against physical coords)
     eBlockFlowMask   = 0x04, // true means vertical-LR (or horizontal-BT if added)
     eLineOrientMask  = 0x08, // true means over != block-start
     eBidiMask        = 0x10, // true means line-relative RTL (bidi RTL)
     // Note: We have one excess bit of info; WritingMode can pack into 4 bits.
     // But since we have space, we're caching interesting things for fast access.
     // Masks for output enums
     eInlineMask = 0x03,
     eBlockMask  = 0x05
   };
 };
 /**
  * Logical-coordinate classes:
  *
  * There are three sets of coordinate space:
  *   - physical (top, left, bottom, right)
  *       relative to graphics coord system
  *   - flow-relative (block-start, inline-start, block-end, inline-end)
  *       relative to block/inline flow directions
  *   - line-relative (line-over, line-left, line-under, line-right)
  *       relative to glyph orientation / inline bidi directions
  * See CSS3 Writing Modes for more information
  *   http://www.w3.org/TR/css3-writing-modes/#abstract-box
  *
  * For shorthand, B represents the block-axis
  *                I represents the inline-axis
  *
  * The flow-relative geometric classes store coords in flow-relative space.
  * They use a private ns{Point,Size,Rect,Margin} member to store the actual
  * coordinate values, but reinterpret them as logical instead of physical.
  * This allows us to easily perform calculations in logical space (provided
  * writing modes of the operands match), by simply mapping to nsPoint (etc)
  * methods.
  *
  * Physical-coordinate accessors/setters are responsible to translate these
  * internal logical values as necessary.
  *
  * In DEBUG builds, the logical types store their WritingMode and check
  * that the same WritingMode is passed whenever callers ask them to do a
  * writing-mode-dependent operation. Non-DEBUG builds do NOT check this,
  * to avoid the overhead of storing WritingMode fields.
  *
  * Open question: do we need a different set optimized for line-relative
  * math, for use in nsLineLayout and the like? Or is multiplying values
  * by FlowRelativeToLineRelativeFactor() enough?
  */
 /**
  * Flow-relative point
  */
 class LogicalPoint {
 public:
   LogicalPoint(WritingMode aWritingMode)
     :
 #ifdef DEBUG
       mWritingMode(aWritingMode),
 #endif
       mPoint(0, 0)
   { }
   // Construct from a writing mode and individual coordinates (which MUST be
   // values in that writing mode, NOT physical coordinates!)
   LogicalPoint(WritingMode aWritingMode, nscoord aI, nscoord aB)
     :
 #ifdef DEBUG
       mWritingMode(aWritingMode),
 #endif
       mPoint(aI, aB)
   { }
   // Construct from a writing mode and a physical point, within a given
   // containing rectangle's width (defining the conversion between LTR
   // and RTL coordinates).
   LogicalPoint(WritingMode aWritingMode,
                const nsPoint& aPoint,
                nscoord aContainerWidth)
 #ifdef DEBUG
     : mWritingMode(aWritingMode)
 #endif
   {
     if (aWritingMode.IsVertical()) {
       I() = aPoint.y;
       B() = aWritingMode.IsVerticalLR() ? aPoint.x : aContainerWidth - aPoint.x;
     } else {
       I() = aWritingMode.IsBidiLTR() ? aPoint.x : aContainerWidth - aPoint.x;
       B() = aPoint.y;
     }
   }
   /**
    * Read-only (const) access to the coordinates, in both logical
    * and physical terms.
    */
   nscoord I(WritingMode aWritingMode) const // inline-axis
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mPoint.x;
   }
   nscoord B(WritingMode aWritingMode) const // block-axis
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mPoint.y;
   }
   nscoord X(WritingMode aWritingMode, nscoord aContainerWidth) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       return aWritingMode.IsVerticalLR() ? B() : aContainerWidth - B();
     } else {
       return aWritingMode.IsBidiLTR() ? I() : aContainerWidth - I();
     }
   }
   nscoord Y(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ? I() : B();
   }
   /**
    * These non-const accessors return a reference (lvalue) that can be
    * assigned to by callers.
    */
   nscoord& I(WritingMode aWritingMode) // inline-axis
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mPoint.x;
   }
   nscoord& B(WritingMode aWritingMode) // block-axis
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mPoint.y;
   }
   /**
    * Setters for the physical coordinates.
    */
   void SetX(WritingMode aWritingMode, nscoord aX, nscoord aContainerWidth)
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       B() = aWritingMode.IsVerticalLR() ? aX : aContainerWidth - aX;
     } else {
       I() = aWritingMode.IsBidiLTR() ? aX : aContainerWidth - aX;
     }
   }
   void SetY(WritingMode aWritingMode, nscoord aY)
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       B() = aY;
     } else {
       I() = aY;
     }
   }
   /**
    * Return a physical point corresponding to our logical coordinates,
    * converted according to our writing mode.
    */
   nsPoint GetPhysicalPoint(WritingMode aWritingMode,
                            nscoord aContainerWidth) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       return nsPoint(aWritingMode.IsVerticalLR() ? B() : aContainerWidth - B(),
                      I());
     } else {
       return nsPoint(aWritingMode.IsBidiLTR() ? I() : aContainerWidth - I(),
                      B());
     }
   }
   /**
    * Return the equivalent point in a different writing mode.
    */
   LogicalPoint ConvertTo(WritingMode aToMode, WritingMode aFromMode,
                          nscoord aContainerWidth) const
   {
     CHECK_WRITING_MODE(aFromMode);
     return aToMode == aFromMode ?
       *this : LogicalPoint(aToMode,
                            GetPhysicalPoint(aFromMode, aContainerWidth),
                            aContainerWidth);
   }
   LogicalPoint operator+(const LogicalPoint& aOther) const
   {
     CHECK_WRITING_MODE(aOther.GetWritingMode());
     // In non-debug builds, LogicalPoint does not store the WritingMode,
     // so the first parameter here (which will always be eUnknownWritingMode)
     // is ignored.
     return LogicalPoint(GetWritingMode(),
                         mPoint.x + aOther.mPoint.x,
                         mPoint.y + aOther.mPoint.y);
   }
 private:
   friend class LogicalRect;
   /**
    * NOTE that in non-DEBUG builds, GetWritingMode() always returns
    * eUnknownWritingMode, as the current mode is not stored in the logical-
    * geometry classes. Therefore, this method is private; it is used ONLY
    * by the DEBUG-mode checking macros in this class and its friends;
    * other code is not allowed to ask a logical point for its writing mode,
    * as this info will simply not be available in non-DEBUG builds.
    *
    * Also, in non-DEBUG builds, CHECK_WRITING_MODE does nothing, and the
    * WritingMode parameter to logical methods will generally be optimized
    * away altogether.
    */
 #ifdef DEBUG
   WritingMode GetWritingMode() const { return mWritingMode; }
 #else
   WritingMode GetWritingMode() const { return WritingMode::Unknown(); }
 #endif
   // We don't allow construction of a LogicalPoint with no writing mode.
   LogicalPoint() MOZ_DELETE;
   // Accessors that don't take or check a WritingMode value.
   // These are for internal use only; they are called by methods that have
   // themselves already checked the WritingMode passed by the caller.
   nscoord I() const // inline-axis
   {
     return mPoint.x;
   }
   nscoord B() const // block-axis
   {
     return mPoint.y;
   }
   nscoord& I() // inline-axis
   {
     return mPoint.x;
   }
   nscoord& B() // block-axis
   {
     return mPoint.y;
   }
   WritingMode mWritingMode;
   // We use an nsPoint to hold the coordinates, but reinterpret its .x and .y
   // fields as the inline and block directions. Hence, this is not exposed
   // directly, but only through accessors that will map them according to the
   // writing mode.
   nsPoint mPoint;
 };
 /**
  * Flow-relative size
  */
 class LogicalSize {
 public:
   LogicalSize(WritingMode aWritingMode)
     :
 #ifdef DEBUG
       mWritingMode(aWritingMode),
 #endif
       mSize(0, 0)
   { }
   LogicalSize(WritingMode aWritingMode, nscoord aISize, nscoord aBSize)
     :
 #ifdef DEBUG
       mWritingMode(aWritingMode),
 #endif
       mSize(aISize, aBSize)
   { }
   LogicalSize(WritingMode aWritingMode, const nsSize& aPhysicalSize)
 #ifdef DEBUG
     : mWritingMode(aWritingMode)
 #endif
   {
     if (aWritingMode.IsVertical()) {
       ISize() = aPhysicalSize.height;
       BSize() = aPhysicalSize.width;
     } else {
       ISize() = aPhysicalSize.width;
       BSize() = aPhysicalSize.height;
     }
   }
   /**
    * Dimensions in logical and physical terms
    */
   nscoord ISize(WritingMode aWritingMode) const // inline-size
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mSize.width;
   }
   nscoord BSize(WritingMode aWritingMode) const // block-size
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mSize.height;
   }
   nscoord Width(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ? BSize() : ISize();
   }
   nscoord Height(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ? ISize() : BSize();
   }
   /**
    * Writable references to the logical dimensions
    */
   nscoord& ISize(WritingMode aWritingMode) // inline-size
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mSize.width;
   }
   nscoord& BSize(WritingMode aWritingMode) // block-size
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mSize.height;
   }
   /**
    * Setters for the physical dimensions
    */
   void SetWidth(WritingMode aWritingMode, nscoord aWidth)
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       BSize() = aWidth;
     } else {
       ISize() = aWidth;
     }
   }
   void SetHeight(WritingMode aWritingMode, nscoord aHeight)
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       ISize() = aHeight;
     } else {
       BSize() = aHeight;
     }
   }
   /**
    * Return an nsSize containing our physical dimensions
    */
   nsSize GetPhysicalSize(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ?
       nsSize(BSize(), ISize()) : nsSize(ISize(), BSize());
   }
   /**
    * Return a LogicalSize representing this size in a different writing mode
    */
   LogicalSize ConvertTo(WritingMode aToMode, WritingMode aFromMode) const
   {
     CHECK_WRITING_MODE(aFromMode);
     return aToMode == aFromMode ?
       *this : LogicalSize(aToMode, GetPhysicalSize(aFromMode));
   }
 private:
   friend class LogicalRect;
   LogicalSize() MOZ_DELETE;
 #ifdef DEBUG
   WritingMode GetWritingMode() const { return mWritingMode; }
 #else
   WritingMode GetWritingMode() const { return WritingMode::Unknown(); }
 #endif
   nscoord ISize() const // inline-size
   {
     return mSize.width;
   }
   nscoord BSize() const // block-size
   {
     return mSize.height;
   }
   nscoord& ISize() // inline-size
   {
     return mSize.width;
   }
   nscoord& BSize() // block-size
   {
     return mSize.height;
   }
   WritingMode mWritingMode;
   nsSize      mSize;
 };
 /**
  * Flow-relative margin
  */
 class LogicalMargin {
 public:
   LogicalMargin(WritingMode aWritingMode)
     :
 #ifdef DEBUG
       mWritingMode(aWritingMode),
 #endif
       mMargin(0, 0, 0, 0)
   { }
   LogicalMargin(WritingMode aWritingMode,
                 nscoord aBStart, nscoord aIEnd,
                 nscoord aBEnd, nscoord aIStart)
     :
 #ifdef DEBUG
       mWritingMode(aWritingMode),
 #endif
       mMargin(aBStart, aIEnd, aBEnd, aIStart)
   { }
   LogicalMargin(WritingMode aWritingMode, const nsMargin& aPhysicalMargin)
 #ifdef DEBUG
     : mWritingMode(aWritingMode)
 #endif
   {
     if (aWritingMode.IsVertical()) {
       if (aWritingMode.IsVerticalLR()) {
         mMargin.top = aPhysicalMargin.left;
         mMargin.bottom = aPhysicalMargin.right;
       } else {
         mMargin.top = aPhysicalMargin.right;
         mMargin.bottom = aPhysicalMargin.left;
       }
       if (aWritingMode.IsBidiLTR()) {
         mMargin.left = aPhysicalMargin.top;
         mMargin.right = aPhysicalMargin.bottom;
       } else {
         mMargin.left = aPhysicalMargin.bottom;
         mMargin.right = aPhysicalMargin.top;
       }
     } else {
       mMargin.top = aPhysicalMargin.top;
       mMargin.bottom = aPhysicalMargin.bottom;
       if (aWritingMode.IsBidiLTR()) {
         mMargin.left = aPhysicalMargin.left;
         mMargin.right = aPhysicalMargin.right;
       } else {
         mMargin.left = aPhysicalMargin.right;
         mMargin.right = aPhysicalMargin.left;
       }
     }
   }
   nscoord IStart(WritingMode aWritingMode) const // inline-start margin
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mMargin.left;
   }
   nscoord IEnd(WritingMode aWritingMode) const // inline-end margin
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mMargin.right;
   }
   nscoord BStart(WritingMode aWritingMode) const // block-start margin
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mMargin.top;
   }
   nscoord BEnd(WritingMode aWritingMode) const // block-end margin
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mMargin.bottom;
   }
   nscoord& IStart(WritingMode aWritingMode) // inline-start margin
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mMargin.left;
   }
   nscoord& IEnd(WritingMode aWritingMode) // inline-end margin
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mMargin.right;
   }
   nscoord& BStart(WritingMode aWritingMode) // block-start margin
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mMargin.top;
   }
   nscoord& BEnd(WritingMode aWritingMode) // block-end margin
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mMargin.bottom;
   }
   nscoord IStartEnd(WritingMode aWritingMode) const // inline margins
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mMargin.LeftRight();
   }
   nscoord BStartEnd(WritingMode aWritingMode) const // block margins
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mMargin.TopBottom();
   }
   /**
    * Accessors for physical margins, using our writing mode to convert from
    * logical values.
    */
   nscoord Top(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ?
       (aWritingMode.IsBidiLTR() ? IStart() : IEnd()) : BStart();
   }
   nscoord Bottom(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ?
       (aWritingMode.IsBidiLTR() ? IEnd() : IStart()) : BEnd();
   }
   nscoord Left(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ?
       (aWritingMode.IsVerticalLR() ? BStart() : BEnd()) :
       (aWritingMode.IsBidiLTR() ? IStart() : IEnd());
   }
   nscoord Right(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ?
       (aWritingMode.IsVerticalLR() ? BEnd() : BStart()) :
       (aWritingMode.IsBidiLTR() ? IEnd() : IStart());
   }
   nscoord LeftRight(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ? BStartEnd() : IStartEnd();
   }
   nscoord TopBottom(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ? IStartEnd() : BStartEnd();
   }
   void SizeTo(WritingMode aWritingMode,
               nscoord aBStart, nscoord aIEnd, nscoord aBEnd, nscoord aIStart)
   {
     CHECK_WRITING_MODE(aWritingMode);
     mMargin.SizeTo(aBStart, aIEnd, aBEnd, aIStart);
   }
   /**
    * Return an nsMargin containing our physical coordinates
    */
   nsMargin GetPhysicalMargin(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ?
       (aWritingMode.IsVerticalLR() ?
         nsMargin(IStart(), BEnd(), IEnd(), BStart()) :
         nsMargin(IStart(), BStart(), IEnd(), BEnd())) :
       (aWritingMode.IsBidiLTR() ?
         nsMargin(BStart(), IEnd(), BEnd(), IStart()) :
         nsMargin(BStart(), IStart(), BEnd(), IEnd()));
   }
   /**
    * Return a LogicalMargin representing this margin in a different
    * writing mode
    */
   LogicalMargin ConvertTo(WritingMode aToMode, WritingMode aFromMode) const
   {
     CHECK_WRITING_MODE(aFromMode);
     return aToMode == aFromMode ?
       *this : LogicalMargin(aToMode, GetPhysicalMargin(aFromMode));
   }
   bool IsEmpty() const
   {
     return (mMargin.left == 0 && mMargin.top == 0 &&
             mMargin.right == 0 && mMargin.bottom == 0);
   }
   LogicalMargin operator+(const LogicalMargin& aMargin) {
     CHECK_WRITING_MODE(aMargin.GetWritingMode());
     return LogicalMargin(GetWritingMode(),
                          BStart() + aMargin.BStart(),
                          IEnd() + aMargin.IEnd(),
                          BEnd() + aMargin.BEnd(),
                          IStart() + aMargin.IStart());
   }
   LogicalMargin operator-(const LogicalMargin& aMargin) {
     CHECK_WRITING_MODE(aMargin.GetWritingMode());
     return LogicalMargin(GetWritingMode(),
                          BStart() - aMargin.BStart(),
                          IEnd() - aMargin.IEnd(),
                          BEnd() - aMargin.BEnd(),
                          IStart() - aMargin.IStart());
   }
 private:
   friend class LogicalRect;
   LogicalMargin() MOZ_DELETE;
 #ifdef DEBUG
   WritingMode GetWritingMode() const { return mWritingMode; }
 #else
   WritingMode GetWritingMode() const { return WritingMode::Unknown(); }
 #endif
   nscoord IStart() const // inline-start margin
   {
     return mMargin.left;
   }
   nscoord IEnd() const // inline-end margin
   {
     return mMargin.right;
   }
   nscoord BStart() const // block-start margin
   {
     return mMargin.top;
   }
   nscoord BEnd() const // block-end margin
   {
     return mMargin.bottom;
   }
   nscoord& IStart() // inline-start margin
   {
     return mMargin.left;
   }
   nscoord& IEnd() // inline-end margin
   {
     return mMargin.right;
   }
   nscoord& BStart() // block-start margin
   {
     return mMargin.top;
   }
   nscoord& BEnd() // block-end margin
   {
     return mMargin.bottom;
   }
   nscoord IStartEnd() const // inline margins
   {
     return mMargin.LeftRight();
   }
   nscoord BStartEnd() const // block margins
   {
     return mMargin.TopBottom();
   }
   WritingMode mWritingMode;
   nsMargin    mMargin;
 };
 /**
  * Flow-relative rectangle
  */
 class LogicalRect {
 public:
   LogicalRect(WritingMode aWritingMode)
     :
 #ifdef DEBUG
       mWritingMode(aWritingMode),
 #endif
       mRect(0, 0, 0, 0)
   { }
   LogicalRect(WritingMode aWritingMode,
               nscoord aIStart, nscoord aBStart,
               nscoord aISize, nscoord aBSize)
     :
 #ifdef DEBUG
       mWritingMode(aWritingMode),
 #endif
       mRect(aIStart, aBStart, aISize, aBSize)
   { }
   LogicalRect(WritingMode aWritingMode,
               const LogicalPoint& aOrigin,
               const LogicalSize& aSize)
     :
 #ifdef DEBUG
       mWritingMode(aWritingMode),
 #endif
       mRect(aOrigin.mPoint, aSize.mSize)
   {
     CHECK_WRITING_MODE(aOrigin.GetWritingMode());
     CHECK_WRITING_MODE(aSize.GetWritingMode());
   }
   LogicalRect(WritingMode aWritingMode,
               const nsRect& aRect,
               nscoord aContainerWidth)
 #ifdef DEBUG
     : mWritingMode(aWritingMode)
 #endif
   {
     if (aWritingMode.IsVertical()) {
       if (aWritingMode.IsVerticalLR()) {
         mRect.y = aRect.x;
       } else {
         mRect.y = aContainerWidth - aRect.XMost();
       }
       mRect.height = aRect.width;
       mRect.x = aRect.y;
       mRect.width = aRect.height;
     } else {
       if (aWritingMode.IsBidiLTR()) {
         mRect.x = aRect.x;
       } else {
         mRect.x = aContainerWidth - aRect.XMost();
       }
       mRect.width = aRect.width;
       mRect.y = aRect.y;
       mRect.height = aRect.height;
     }
   }
   /**
    * Inline- and block-dimension geometry.
    */
   nscoord IStart(WritingMode aWritingMode) const // inline-start edge
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mRect.X();
   }
   nscoord IEnd(WritingMode aWritingMode) const // inline-end edge
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mRect.XMost();
   }
   nscoord ISize(WritingMode aWritingMode) const // inline-size
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mRect.Width();
   }
   nscoord BStart(WritingMode aWritingMode) const // block-start edge
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mRect.Y();
   }
   nscoord BEnd(WritingMode aWritingMode) const // block-end edge
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mRect.YMost();
   }
   nscoord BSize(WritingMode aWritingMode) const // block-size
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mRect.Height();
   }
   /**
    * Writable (reference) accessors are only available for the basic logical
    * fields (Start and Size), not derivatives like End.
    */
   nscoord& IStart(WritingMode aWritingMode) // inline-start edge
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mRect.x;
   }
   nscoord& ISize(WritingMode aWritingMode) // inline-size
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mRect.width;
   }
   nscoord& BStart(WritingMode aWritingMode) // block-start edge
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mRect.y;
   }
   nscoord& BSize(WritingMode aWritingMode) // block-size
   {
     CHECK_WRITING_MODE(aWritingMode);
     return mRect.height;
   }
   /**
    * Physical coordinates of the rect.
    */
   nscoord X(WritingMode aWritingMode, nscoord aContainerWidth) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       return aWritingMode.IsVerticalLR() ?
              mRect.Y() : aContainerWidth - mRect.YMost();
     } else {
       return aWritingMode.IsBidiLTR() ?
              mRect.X() : aContainerWidth - mRect.XMost();
     }
   }
   void SetX(WritingMode aWritingMode, nscoord aX, nscoord aContainerWidth)
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       if (aWritingMode.IsVerticalLR()) {
         BStart() = aX;
       } else {
         BStart() = aContainerWidth - aX - BSize();
       }
     } else {
       if (aWritingMode.IsBidiLTR()) {
         IStart() = aX;
       } else {
         IStart() = aContainerWidth - aX - ISize();
       }
     }
   }
   nscoord Y(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ? mRect.X() : mRect.Y();
   }
   void SetY(WritingMode aWritingMode, nscoord aY)
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       IStart() = aY;
     } else {
       BStart() = aY;
     }
   }
   nscoord Width(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ? mRect.Height() : mRect.Width();
   }
   // When setting the Width of a rect, we keep its physical X-coord fixed
   // and modify XMax. This means that in the RTL case, we'll be moving
   // the IStart, so that IEnd remains constant.
   void SetWidth(WritingMode aWritingMode, nscoord aWidth)
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       if (!aWritingMode.IsVerticalLR()) {
         BStart() = BStart() + BSize() - aWidth;
       }
       BSize() = aWidth;
     } else {
       if (!aWritingMode.IsBidiLTR()) {
         IStart() = IStart() + ISize() - aWidth;
       }
       ISize() = aWidth;
     }
   }
   nscoord Height(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ? mRect.Width() : mRect.Height();
   }
   void SetHeight(WritingMode aWritingMode, nscoord aHeight)
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       ISize() = aHeight;
     } else {
       BSize() = aHeight;
     }
   }
   nscoord XMost(WritingMode aWritingMode, nscoord aContainerWidth) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       return aWritingMode.IsVerticalLR() ?
              mRect.YMost() : aContainerWidth - mRect.Y();
     } else {
       return aWritingMode.IsBidiLTR() ?
              mRect.XMost() : aContainerWidth - mRect.X();
     }
   }
   nscoord YMost(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsVertical() ? mRect.XMost() : mRect.YMost();
   }
   bool IsEmpty() const
   {
     return (mRect.x == 0 && mRect.y == 0 &&
             mRect.width == 0 && mRect.height == 0);
   }
   bool IsZeroSize() const
   {
     return (mRect.width == 0 && mRect.height == 0);
   }
 /* XXX are these correct?
   nscoord ILeft(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsBidiLTR() ? IStart() : IEnd();
   }
   nscoord IRight(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return aWritingMode.IsBidiLTR() ? IEnd() : IStart();
   }
 */
   LogicalPoint Origin(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return LogicalPoint(aWritingMode, IStart(), BStart());
   }
   LogicalSize Size(WritingMode aWritingMode) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     return LogicalSize(aWritingMode, ISize(), BSize());
   }
   LogicalRect operator+(const LogicalPoint& aPoint) const
   {
     CHECK_WRITING_MODE(aPoint.GetWritingMode());
     return LogicalRect(GetWritingMode(),
                        IStart() + aPoint.I(), BStart() + aPoint.B(),
                        ISize(), BSize());
   }
   LogicalRect& operator+=(const LogicalPoint& aPoint)
   {
     CHECK_WRITING_MODE(aPoint.GetWritingMode());
     mRect += aPoint.mPoint;
     return *this;
   }
   LogicalRect operator-(const LogicalPoint& aPoint) const
   {
     CHECK_WRITING_MODE(aPoint.GetWritingMode());
     return LogicalRect(GetWritingMode(),
                        IStart() - aPoint.I(), BStart() - aPoint.B(),
                        ISize(), BSize());
   }
   LogicalRect& operator-=(const LogicalPoint& aPoint)
   {
     CHECK_WRITING_MODE(aPoint.GetWritingMode());
     mRect -= aPoint.mPoint;
     return *this;
   }
   void MoveBy(WritingMode aWritingMode, const LogicalPoint& aDelta)
   {
     CHECK_WRITING_MODE(aWritingMode);
     CHECK_WRITING_MODE(aDelta.GetWritingMode());
     IStart() += aDelta.I();
     BStart() += aDelta.B();
   }
   void Inflate(nscoord aD) { mRect.Inflate(aD); }
   void Inflate(nscoord aDI, nscoord aDB) { mRect.Inflate(aDI, aDB); }
   void Inflate(WritingMode aWritingMode, const LogicalMargin& aMargin)
   {
     CHECK_WRITING_MODE(aWritingMode);
     CHECK_WRITING_MODE(aMargin.GetWritingMode());
     mRect.Inflate(aMargin.mMargin);
   }
   void Deflate(nscoord aD) { mRect.Deflate(aD); }
   void Deflate(nscoord aDI, nscoord aDB) { mRect.Deflate(aDI, aDB); }
   void Deflate(WritingMode aWritingMode, const LogicalMargin& aMargin)
   {
     CHECK_WRITING_MODE(aWritingMode);
     CHECK_WRITING_MODE(aMargin.GetWritingMode());
     mRect.Deflate(aMargin.mMargin);
   }
   /**
    * Return an nsRect containing our physical coordinates within the given
    * container width
    */
   nsRect GetPhysicalRect(WritingMode aWritingMode,
                          nscoord aContainerWidth) const
   {
     CHECK_WRITING_MODE(aWritingMode);
     if (aWritingMode.IsVertical()) {
       return nsRect(aWritingMode.IsVerticalLR() ?
                       BStart() : aContainerWidth - BEnd(),
                     IStart(), BSize(), ISize());
     } else {
       return nsRect(aWritingMode.IsBidiLTR() ?
                       IStart() : aContainerWidth - IEnd(),
                     BStart(), ISize(), BSize());
     }
   }
 #if 0 // XXX this would require aContainerWidth as well
   /**
    * Return a LogicalRect representing this rect in a different writing mode
    */
   LogicalRect ConvertTo(WritingMode aToMode, WritingMode aFromMode) const
   {
     CHECK_WRITING_MODE(aFromMode);
     return aToMode == aFromMode ?
       *this : LogicalRect(aToMode, GetPhysicalRect(aFromMode));
   }
 #endif
 private:
   LogicalRect() MOZ_DELETE;
 #ifdef DEBUG
   WritingMode GetWritingMode() const { return mWritingMode; }
 #else
   WritingMode GetWritingMode() const { return WritingMode::Unknown(); }
 #endif
   nscoord IStart() const // inline-start edge
   {
     return mRect.X();
   }
   nscoord IEnd() const // inline-end edge
   {
     return mRect.XMost();
   }
   nscoord ISize() const // inline-size
   {
     return mRect.Width();
   }
   nscoord BStart() const // block-start edge
   {
     return mRect.Y();
   }
   nscoord BEnd() const // block-end edge
   {
     return mRect.YMost();
   }
   nscoord BSize() const // block-size
   {
     return mRect.Height();
   }
   nscoord& IStart() // inline-start edge
   {
     return mRect.x;
   }
   nscoord& ISize() // inline-size
   {
     return mRect.width;
   }
   nscoord& BStart() // block-start edge
   {
     return mRect.y;
   }
   nscoord& BSize() // block-size
   {
     return mRect.height;
   }
   WritingMode mWritingMode;
   nsRect      mRect;
 };
 } // namespace mozilla
 #endif // WritingModes_h_

The Tor Browser / annotate

layout/generic/WritingModes.h@b8a032363ba2 (annotated)

layout/generic/WritingModes.h