layout/generic/RubyUtils.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_RubyUtils_h_
   8 #define mozilla_RubyUtils_h_
   9
  10 #include "nsGkAtoms.h"
  11 #include "nsRubyBaseContainerFrame.h"
  12 #include "nsRubyTextContainerFrame.h"
  13
  14 namespace mozilla {
  15
  16 /**
  17  * Reserved ISize
  18  *
  19  * With some exceptions, each ruby internal box has two isizes, which
  20  * are the reflowed isize and the final isize. The reflowed isize is
  21  * what a box itself needs. It is determined when the box gets reflowed.
  22  *
  23  * The final isize is what a box should be as the final result. For a
  24  * ruby base/text box, the final isize is the size of its ruby column.
  25  * For a ruby base/text container, the final isize is the size of its
  26  * ruby segment. The final isize is never smaller than the reflowed
  27  * isize. It is initially determined when a ruby column/segment gets
  28  * fully reflowed, and may be advanced when a box is expanded, e.g.
  29  * for justification.
  30  *
  31  * The difference between the reflowed isize and the final isize is
  32  * reserved in the line layout after reflowing a box, hence it is called
  33  * "Reserved ISize" here. It is used to expand the ruby boxes from their
  34  * reflowed isize to the final isize during alignment of the line.
  35  *
  36  * There are three exceptions for the final isize:
  37  * 1. A ruby text container has a larger final isize only if it is for
  38  *    a span or collapsed annotations.
  39  * 2. A ruby base container has a larger final isize only if at least
  40  *    one of its ruby text containers does.
  41  * 3. If a ruby text container has a larger final isize, its children
  42  *    must not have.
  43  */
  44
  45 class RubyUtils
  46 {
  47 public:
  48   static inline bool IsExpandableRubyBox(nsIFrame* aFrame)
  49   {
  50     nsIAtom* type = aFrame->GetType();
  51     return type == nsGkAtoms::rubyBaseFrame ||
  52            type == nsGkAtoms::rubyTextFrame ||
  53            type == nsGkAtoms::rubyBaseContainerFrame ||
  54            type == nsGkAtoms::rubyTextContainerFrame;
  55   }
  56
  57   static void SetReservedISize(nsIFrame* aFrame, nscoord aISize);
  58   static void ClearReservedISize(nsIFrame* aFrame);
  59   static nscoord GetReservedISize(nsIFrame* aFrame);
  60 };
  61
  62 /**
  63  * This class iterates all ruby text containers paired with
  64  * the given ruby base container.
  65  */
  66 class MOZ_STACK_CLASS RubyTextContainerIterator
  67 {
  68 public:
  69   explicit RubyTextContainerIterator(nsRubyBaseContainerFrame* aBaseContainer);
  70
  71   void Next();
  72   bool AtEnd() const { return !mFrame; }
  73   nsRubyTextContainerFrame* GetTextContainer() const
  74   {
  75     return static_cast<nsRubyTextContainerFrame*>(mFrame);
  76   }
  77
  78 private:
  79   nsIFrame* mFrame;
  80 };
  81
  82 }
  83
  84 #endif /* !defined(mozilla_RubyUtils_h_) */