layout/generic/CSSAlignUtils.h

   1 /* -*- Mode: C++; tab-width: 8; 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 /* Utility code for performing CSS Box Alignment */
   8
   9 #ifndef mozilla_CSSAlignUtils_h
  10 #define mozilla_CSSAlignUtils_h
  11
  12 #include "mozilla/WritingModes.h"
  13
  14 namespace mozilla {
  15
  16 struct ReflowInput;
  17
  18 class CSSAlignUtils {
  19  public:
  20   /**
  21    * Flags to customize the behavior of AlignJustifySelf:
  22    */
  23   enum class AlignJustifyFlags {
  24     NoFlags = 0,
  25     // Indicates that we have <overflow-position> = safe.
  26     OverflowSafe = 1 << 0,
  27     // Indicates that the container's start side in aAxis is the same
  28     // as the child's start side in the child's parallel axis.
  29     SameSide = 1 << 1,
  30     // Indicates that AlignJustifySelf() shouldn't expand "auto" margins.
  31     // (By default, AlignJustifySelf() *will* expand such margins, to fill the
  32     // available space before any alignment is done.)
  33     IgnoreAutoMargins = 1 << 2,
  34   };
  35
  36   /**
  37    * This computes the aligned offset of a CSS-aligned child within its
  38    * alignment container. The returned offset is distance between the
  39    * logical "start" edge of the alignment container & the logical "start" edge
  40    * of the aligned child (in terms of the alignment container's writing mode).
  41    *
  42    * @param aAlignment An enumerated value representing a keyword for
  43    *                   "align-self" or "justify-self". The values
  44    *                   NS_STYLE_ALIGN_{AUTO,LEFT,RIGHT} must *not* be
  45    *                   passed here; this method expects the caller to have
  46    *                   already resolved those to 'start', 'end', or 'stretch'.
  47    * @param aAxis The container's axis in which we're doing alignment.
  48    * @param aBaselineAdjust The amount to offset baseline-aligned children.
  49    * @param aCBSize The size of the alignment container, in its aAxis.
  50    * @param aRI A ReflowInput for the child.
  51    * @param aChildSize The child's LogicalSize (in its own writing mode).
  52    */
  53   static nscoord AlignJustifySelf(uint8_t aAlignment, LogicalAxis aAxis,
  54                                   AlignJustifyFlags aFlags,
  55                                   nscoord aBaselineAdjust, nscoord aCBSize,
  56                                   const ReflowInput& aRI,
  57                                   const LogicalSize& aChildSize);
  58 };
  59
  60 MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(CSSAlignUtils::AlignJustifyFlags)
  61
  62 }  // namespace mozilla
  63
  64 #endif  // mozilla_CSSAlignUtils_h