gecko-dev/layout/base/nsChangeHint.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/* constants for what needs to be recomputed in response to style changes */

#ifndef nsChangeHint_h___
#define nsChangeHint_h___

#include "prtypes.h"

// Defines for various style related constants

enum nsChangeHint {
  // change was visual only (e.g., COLOR=)
  nsChangeHint_RepaintFrame = 0x01,

  // For reflow, we want flags to give us arbitrary FrameNeedsReflow behavior.
  // just do a FrameNeedsReflow
  nsChangeHint_NeedReflow = 0x02,

  // Invalidate intrinsic widths on the frame's ancestors.  Must not be set
  // without setting nsChangeHint_NeedReflow.
  nsChangeHint_ClearAncestorIntrinsics = 0x04,

  // Invalidate intrinsic widths on the frame's descendants.  Must not be set
  // without also setting nsChangeHint_ClearAncestorIntrinsics.
  nsChangeHint_ClearDescendantIntrinsics = 0x08,

  // Force unconditional reflow of all descendants.  Must not be set without
  // setting nsChangeHint_NeedReflow, but is independent of both the
  // Clear*Intrinsics flags.
  nsChangeHint_NeedDirtyReflow = 0x10,

  // change requires view to be updated, if there is one (e.g., clip:)
  nsChangeHint_SyncFrameView = 0x20,

  // The currently shown mouse cursor needs to be updated
  nsChangeHint_UpdateCursor = 0x40,

  /**
   * SVG filter/mask/clip effects need to be recomputed because the URI
   * in the filter/mask/clip-path property has changed. This wipes
   * out cached nsSVGPropertyBase and subclasses which hold a reference to
   * the element referenced by the URI, and a mutation observer for
   * the DOM subtree rooted at that element. Also, for filters they store a
   * bounding-box for the filter result so that if the filter changes we can
   * invalidate the old covered area.
   */
  nsChangeHint_UpdateEffects = 0x80,

  // change requires frame change (e.g., display:).
  // This subsumes all the above.
  nsChangeHint_ReconstructFrame = 0x100
};

// Redefine these operators to return nothing. This will catch any use
// of these operators on hints. We should not be using these operators
// on nsChangeHints
inline void operator<(nsChangeHint s1, nsChangeHint s2) {}
inline void operator>(nsChangeHint s1, nsChangeHint s2) {}
inline void operator!=(nsChangeHint s1, nsChangeHint s2) {}
inline void operator==(nsChangeHint s1, nsChangeHint s2) {}
inline void operator<=(nsChangeHint s1, nsChangeHint s2) {}
inline void operator>=(nsChangeHint s1, nsChangeHint s2) {}

// Operators on nsChangeHints

// Merge two hints, taking the union
inline nsChangeHint NS_CombineHint(nsChangeHint aH1, nsChangeHint aH2) {
  return (nsChangeHint)(aH1 | aH2);
}

// Merge two hints, taking the union
inline nsChangeHint NS_SubtractHint(nsChangeHint aH1, nsChangeHint aH2) {
  return (nsChangeHint)(aH1 & ~aH2);
}

// Merge the "src" hint into the "dst" hint
// Returns true iff the destination changed
inline PRBool NS_UpdateHint(nsChangeHint& aDest, nsChangeHint aSrc) {
  nsChangeHint r = (nsChangeHint)(aDest | aSrc);
  PRBool changed = (int)r != (int)aDest;
  aDest = r;
  return changed;
}

// Returns true iff the second hint contains all the hints of the first hint
inline PRBool NS_IsHintSubset(nsChangeHint aSubset, nsChangeHint aSuperSet) {
  return (aSubset & aSuperSet) == aSubset;
}

// Redefine the old NS_STYLE_HINT constants in terms of the new hint structure
#define NS_STYLE_HINT_NONE \
  nsChangeHint(0)
#define NS_STYLE_HINT_VISUAL \
  nsChangeHint(nsChangeHint_RepaintFrame | nsChangeHint_SyncFrameView)
#define nsChangeHint_ReflowFrame                        \
  nsChangeHint(nsChangeHint_NeedReflow |                \
               nsChangeHint_ClearAncestorIntrinsics |   \
               nsChangeHint_ClearDescendantIntrinsics | \
               nsChangeHint_NeedDirtyReflow)
#define NS_STYLE_HINT_REFLOW \
  nsChangeHint(NS_STYLE_HINT_VISUAL | nsChangeHint_ReflowFrame)
#define NS_STYLE_HINT_FRAMECHANGE \
  nsChangeHint(NS_STYLE_HINT_REFLOW | nsChangeHint_ReconstructFrame)

/**
 * |nsRestyleHint| is a bitfield for the result of |HasStateDependentStyle|
 * and |HasAttributeDependentStyle|.  All values have an implied "and
 * descendants."  When no restyling is necessary, use |nsRestyleHint(0)|.
 */
enum nsRestyleHint {
  eRestyle_Self = 0x1,
  eRestyle_LaterSiblings = 0x2
};


#endif /* nsChangeHint_h___ */