зеркало из https://github.com/mozilla/gecko-dev.git
410 строки
16 KiB
C++
410 строки
16 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla MathML Project.
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*
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* The Initial Developer of the Original Code is
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* The University Of Queensland.
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* Portions created by the Initial Developer are Copyright (C) 1999
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Roger B. Sidje <rbs@maths.uq.edu.au>
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* David J. Fiddes <D.J.Fiddes@hw.ac.uk>
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* Shyjan Mahamud <mahamud@cs.cmu.edu>
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* Pierre Phaneuf <pp@ludusdesign.com>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#include "nsCOMPtr.h"
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#include "nsFrame.h"
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#include "nsPresContext.h"
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#include "nsStyleContext.h"
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#include "nsStyleConsts.h"
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#include "nsINameSpaceManager.h"
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#include "nsRenderingContext.h"
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#include "nsMathMLmoverFrame.h"
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#include "nsMathMLmsupFrame.h"
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//
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// <mover> -- attach an overscript to a base - implementation
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//
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nsIFrame*
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NS_NewMathMLmoverFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
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{
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return new (aPresShell) nsMathMLmoverFrame(aContext);
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}
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NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmoverFrame)
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nsMathMLmoverFrame::~nsMathMLmoverFrame()
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{
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}
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NS_IMETHODIMP
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nsMathMLmoverFrame::AttributeChanged(PRInt32 aNameSpaceID,
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nsIAtom* aAttribute,
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PRInt32 aModType)
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{
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if (nsGkAtoms::accent_ == aAttribute) {
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// When we have automatic data to update within ourselves, we ask our
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// parent to re-layout its children
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return ReLayoutChildren(mParent);
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}
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return nsMathMLContainerFrame::
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AttributeChanged(aNameSpaceID, aAttribute, aModType);
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}
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NS_IMETHODIMP
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nsMathMLmoverFrame::UpdatePresentationData(PRUint32 aFlagsValues,
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PRUint32 aFlagsToUpdate)
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{
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nsMathMLContainerFrame::UpdatePresentationData(aFlagsValues, aFlagsToUpdate);
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// disable the stretch-all flag if we are going to act like a superscript
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if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
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!NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
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mPresentationData.flags &= ~NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
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}
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else {
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mPresentationData.flags |= NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
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}
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return NS_OK;
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}
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NS_IMETHODIMP
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nsMathMLmoverFrame::UpdatePresentationDataFromChildAt(PRInt32 aFirstIndex,
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PRInt32 aLastIndex,
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PRUint32 aFlagsValues,
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PRUint32 aFlagsToUpdate)
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{
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// mover is special... The REC says:
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// Within overscript, <mover> always sets displaystyle to "false",
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// but increments scriptlevel by 1 only when accent is "false".
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// This means that
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// 1. don't allow displaystyle to change in the overscript
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// 2. if the value of the accent is changed, we need to recompute the
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// scriptlevel of the overscript. The problem is that the accent
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// can change in the <mo> deep down the embellished hierarchy
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// Do #1 here, never allow displaystyle to be changed in the overscript
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PRInt32 index = 0;
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nsIFrame* childFrame = mFrames.FirstChild();
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while (childFrame) {
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if ((index >= aFirstIndex) &&
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((aLastIndex <= 0) || ((aLastIndex > 0) && (index <= aLastIndex)))) {
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if (index > 0) {
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// disable the flag
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aFlagsToUpdate &= ~NS_MATHML_DISPLAYSTYLE;
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aFlagsValues &= ~NS_MATHML_DISPLAYSTYLE;
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}
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PropagatePresentationDataFor(childFrame, aFlagsValues, aFlagsToUpdate);
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}
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index++;
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childFrame = childFrame->GetNextSibling();
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}
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return NS_OK;
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// For #2, changing the accent attribute will trigger a re-build of
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// all automatic data in the embellished hierarchy
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}
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NS_IMETHODIMP
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nsMathMLmoverFrame::InheritAutomaticData(nsIFrame* aParent)
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{
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// let the base class get the default from our parent
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nsMathMLContainerFrame::InheritAutomaticData(aParent);
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mPresentationData.flags |= NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsMathMLmoverFrame::TransmitAutomaticData()
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{
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// At this stage, all our children are in sync and we can fully
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// resolve our own mEmbellishData struct
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//---------------------------------------------------------------------
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/* The REC says:
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The default value of accent is false, unless overscript
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is an <mo> element or an embellished operator. If overscript is
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an <mo> element, the value of its accent attribute is used as
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the default value of accent. If overscript is an embellished
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operator, the accent attribute of the <mo> element at its
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core is used as the default value. As with all attributes, an
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explicitly given value overrides the default.
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XXX The winner is the outermost in conflicting settings like these:
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<mover accent='true'>
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<mi>...</mi>
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<mo accent='false'> ... </mo>
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</mover>
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*/
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nsIFrame* overscriptFrame = nsnull;
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nsIFrame* baseFrame = mFrames.FirstChild();
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if (baseFrame)
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overscriptFrame = baseFrame->GetNextSibling();
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// if our base is an embellished operator, let its state bubble to us (in particular,
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// this is where we get the flag for NS_MATHML_EMBELLISH_MOVABLELIMITS). Our flags
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// are reset to the default values of false if the base frame isn't embellished.
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mPresentationData.baseFrame = baseFrame;
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GetEmbellishDataFrom(baseFrame, mEmbellishData);
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// The default value of accent is false, unless the overscript is embellished
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// and its core <mo> is an accent
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nsEmbellishData embellishData;
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GetEmbellishDataFrom(overscriptFrame, embellishData);
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if (NS_MATHML_EMBELLISH_IS_ACCENT(embellishData.flags))
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mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTOVER;
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else
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mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTOVER;
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// if we have an accent attribute, it overrides what the overscript said
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nsAutoString value;
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if (GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::accent_,
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value)) {
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if (value.EqualsLiteral("true")) {
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mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTOVER;
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} else if (value.EqualsLiteral("false")) {
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mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTOVER;
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}
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}
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// disable the stretch-all flag if we are going to act like a superscript
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if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
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!NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags))
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mPresentationData.flags &= ~NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
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// Now transmit any change that we want to our children so that they
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// can update their mPresentationData structs
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//---------------------------------------------------------------------
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/* The REC says:
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Within overscript, <mover> always sets displaystyle to "false",
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but increments scriptlevel by 1 only when accent is "false".
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The TeXBook treats 'over' like a superscript, so p.141 or Rule 13a
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say it shouldn't be compressed. However, The TeXBook says
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that math accents and \overline change uncramped styles to their
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cramped counterparts.
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*/
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SetIncrementScriptLevel(1, !NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags));
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PRUint32 compress = NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags)
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? NS_MATHML_COMPRESSED : 0;
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PropagatePresentationDataFor(overscriptFrame,
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~NS_MATHML_DISPLAYSTYLE | compress,
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NS_MATHML_DISPLAYSTYLE | compress);
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return NS_OK;
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}
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/*
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The REC says:
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* If the base is an operator with movablelimits="true" (or an embellished
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operator whose <mo> element core has movablelimits="true"), and
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displaystyle="false", then overscript is drawn in a superscript
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position. In this case, the accent attribute is ignored. This is
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often used for limits on symbols such as ∑.
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i.e.:
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if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
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!NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
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// place like superscript
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}
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else {
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// place like overscript
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}
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*/
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/* virtual */ nsresult
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nsMathMLmoverFrame::Place(nsRenderingContext& aRenderingContext,
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PRBool aPlaceOrigin,
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nsHTMLReflowMetrics& aDesiredSize)
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{
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if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
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!NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
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// place like superscript
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return nsMathMLmsupFrame::PlaceSuperScript(PresContext(),
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aRenderingContext,
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aPlaceOrigin,
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aDesiredSize,
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this, 0, nsPresContext::CSSPointsToAppUnits(0.5f));
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}
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////////////////////////////////////
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// Get the children's desired sizes
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nsBoundingMetrics bmBase, bmOver;
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nsHTMLReflowMetrics baseSize;
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nsHTMLReflowMetrics overSize;
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nsIFrame* overFrame = nsnull;
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nsIFrame* baseFrame = mFrames.FirstChild();
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if (baseFrame)
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overFrame = baseFrame->GetNextSibling();
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if (!baseFrame || !overFrame || overFrame->GetNextSibling()) {
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// report an error, encourage people to get their markups in order
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return ReflowError(aRenderingContext, aDesiredSize);
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}
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GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
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GetReflowAndBoundingMetricsFor(overFrame, overSize, bmOver);
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nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
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////////////////////
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// Place Children
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aRenderingContext.SetFont(GetStyleFont()->mFont,
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PresContext()->GetUserFontSet());
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nsFontMetrics* fm = aRenderingContext.FontMetrics();
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nscoord xHeight = fm->XHeight();
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nscoord ruleThickness;
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GetRuleThickness (aRenderingContext, fm, ruleThickness);
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// there are 2 different types of placement depending on
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// whether we want an accented overscript or not
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nscoord correction = 0;
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GetItalicCorrection (bmBase, correction);
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nscoord delta1 = 0; // gap between base and overscript
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nscoord delta2 = 0; // extra space above overscript
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if (!NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags)) {
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// Rule 13a, App. G, TeXbook
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nscoord bigOpSpacing1, bigOpSpacing3, bigOpSpacing5, dummy;
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GetBigOpSpacings (fm,
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bigOpSpacing1, dummy,
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bigOpSpacing3, dummy,
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bigOpSpacing5);
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delta1 = NS_MAX(bigOpSpacing1, (bigOpSpacing3 - bmOver.descent));
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delta2 = bigOpSpacing5;
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// XXX This is not a TeX rule...
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// delta1 (as computed above) can become really big when bmOver.descent is
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// negative, e.g., if the content is &OverBar. In such case, we use the height
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if (bmOver.descent < 0)
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delta1 = NS_MAX(bigOpSpacing1, (bigOpSpacing3 - (bmOver.ascent + bmOver.descent)));
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}
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else {
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// Rule 12, App. G, TeXbook
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// We are going to modify this rule to make it more general.
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// The idea behind Rule 12 in the TeXBook is to keep the accent
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// as close to the base as possible, while ensuring that the
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// distance between the *baseline* of the accent char and
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// the *baseline* of the base is atleast x-height.
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// The idea is that for normal use, we would like all the accents
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// on a line to line up atleast x-height above the baseline
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// if possible.
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// When the ascent of the base is >= x-height,
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// the baseline of the accent char is placed just above the base
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// (specifically, the baseline of the accent char is placed
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// above the baseline of the base by the ascent of the base).
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// For ease of implementation,
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// this assumes that the font-designer designs accents
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// in such a way that the bottom of the accent is atleast x-height
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// above its baseline, otherwise there will be collisions
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// with the base. Also there should be proper padding between
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// the bottom of the accent char and its baseline.
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// The above rule may not be obvious from a first
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// reading of rule 12 in the TeXBook !!!
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// The mathml <mover> tag can use accent chars that
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// do not follow this convention. So we modify TeX's rule
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// so that TeX's rule gets subsumed for accents that follow
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// TeX's convention,
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// while also allowing accents that do not follow the convention :
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// we try to keep the *bottom* of the accent char atleast x-height
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// from the baseline of the base char. we also slap on an extra
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// padding between the accent and base chars.
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delta1 = ruleThickness + onePixel/2; // we have at least the padding
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if (bmBase.ascent < xHeight) {
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// also ensure at least x-height above the baseline of the base
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delta1 += xHeight - bmBase.ascent;
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}
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delta2 = ruleThickness;
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}
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// empty over?
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if (!(bmOver.ascent + bmOver.descent)) delta1 = 0;
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nscoord dxBase, dxOver = 0;
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// Ad-hoc - This is to override fonts which have ready-made _accent_
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// glyphs with negative lbearing and rbearing. We want to position
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// the overscript ourselves
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nscoord overWidth = bmOver.width;
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if (!overWidth && (bmOver.rightBearing - bmOver.leftBearing > 0)) {
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overWidth = bmOver.rightBearing - bmOver.leftBearing;
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dxOver = -bmOver.leftBearing;
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}
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if (NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags)) {
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mBoundingMetrics.width = bmBase.width;
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dxOver += correction + (mBoundingMetrics.width - overWidth)/2;
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}
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else {
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mBoundingMetrics.width = NS_MAX(bmBase.width, overWidth);
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dxOver += correction/2 + (mBoundingMetrics.width - overWidth)/2;
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}
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dxBase = (mBoundingMetrics.width - bmBase.width) / 2;
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mBoundingMetrics.ascent =
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bmOver.ascent + bmOver.descent + delta1 + bmBase.ascent;
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mBoundingMetrics.descent = bmBase.descent;
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mBoundingMetrics.leftBearing =
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NS_MIN(dxBase + bmBase.leftBearing, dxOver + bmOver.leftBearing);
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mBoundingMetrics.rightBearing =
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NS_MAX(dxBase + bmBase.rightBearing, dxOver + bmOver.rightBearing);
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aDesiredSize.ascent =
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NS_MAX(mBoundingMetrics.ascent + delta2,
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overSize.ascent + bmOver.descent + delta1 + bmBase.ascent);
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aDesiredSize.height = aDesiredSize.ascent +
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baseSize.height - baseSize.ascent;
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aDesiredSize.width = mBoundingMetrics.width;
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aDesiredSize.mBoundingMetrics = mBoundingMetrics;
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mReference.x = 0;
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mReference.y = aDesiredSize.ascent;
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if (aPlaceOrigin) {
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// place base
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nscoord dy = aDesiredSize.ascent - baseSize.ascent;
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FinishReflowChild (baseFrame, PresContext(), nsnull, baseSize, dxBase, dy, 0);
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// place overscript
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dy = aDesiredSize.ascent -
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mBoundingMetrics.ascent + bmOver.ascent - overSize.ascent;
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FinishReflowChild (overFrame, PresContext(), nsnull, overSize, dxOver, dy, 0);
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}
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return NS_OK;
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}
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