gecko/layout/mathml/nsMathMLmsubFrame.cpp
L. David Baron 2c717f398d Switch lots of callers to using nsLayoutUtils::GetFontMetricsForFrame and nsLayoutUtils::GetFontMetricsForStyleContext. (Bug 678671, patch 1) r=roc
This changes a number of callers that were previously bypassing the use
of the correct language (with either no language or the charset-detected
language on the pres context via nsPresContext::GetMetricsFor) and/or
the correct user font set to pass the correct values, which should
improve the correctness of the behavior of whatever they were using the
fonts for, and also reduce the number of unique sets of font metrics
requested (which helps nsFontCache effectiveness).
2011-08-14 10:08:04 -07:00

216 lines
8.2 KiB
C++

/* -*- 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 MathML Project.
*
* The Initial Developer of the Original Code is
* The University Of Queensland.
* Portions created by the Initial Developer are Copyright (C) 1999
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Roger B. Sidje <rbs@maths.uq.edu.au>
* David J. Fiddes <D.J.Fiddes@hw.ac.uk>
* Shyjan Mahamud <mahamud@cs.cmu.edu> (added TeX rendering rules)
*
* 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
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* 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 ***** */
#include "nsCOMPtr.h"
#include "nsFrame.h"
#include "nsPresContext.h"
#include "nsStyleContext.h"
#include "nsStyleConsts.h"
#include "nsMathMLmsubFrame.h"
//
// <msub> -- attach a subscript to a base - implementation
//
nsIFrame*
NS_NewMathMLmsubFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
{
return new (aPresShell) nsMathMLmsubFrame(aContext);
}
NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmsubFrame)
nsMathMLmsubFrame::~nsMathMLmsubFrame()
{
}
NS_IMETHODIMP
nsMathMLmsubFrame::TransmitAutomaticData()
{
// if our base is an embellished operator, let its state bubble to us
mPresentationData.baseFrame = mFrames.FirstChild();
GetEmbellishDataFrom(mPresentationData.baseFrame, mEmbellishData);
// 1. The REC says:
// The <msub> element increments scriptlevel by 1, and sets displaystyle to
// "false", within subscript, but leaves both attributes unchanged within base.
// 2. The TeXbook (Ch 17. p.141) says the subscript is compressed
UpdatePresentationDataFromChildAt(1, -1,
~NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED,
NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED);
return NS_OK;
}
/* virtual */ nsresult
nsMathMLmsubFrame::Place (nsRenderingContext& aRenderingContext,
PRBool aPlaceOrigin,
nsHTMLReflowMetrics& aDesiredSize)
{
// extra spacing after sup/subscript
nscoord scriptSpace = nsPresContext::CSSPointsToAppUnits(0.5f); // 0.5pt as in plain TeX
// check if the subscriptshift attribute is there
nscoord subScriptShift = 0;
nsAutoString value;
GetAttribute(mContent, mPresentationData.mstyle,
nsGkAtoms::subscriptshift_, value);
if (!value.IsEmpty()) {
nsCSSValue cssValue;
if (ParseNumericValue(value, cssValue) && cssValue.IsLengthUnit()) {
subScriptShift = CalcLength(PresContext(), mStyleContext, cssValue);
}
}
return nsMathMLmsubFrame::PlaceSubScript(PresContext(),
aRenderingContext,
aPlaceOrigin,
aDesiredSize,
this,
subScriptShift,
scriptSpace);
}
// exported routine that both munder and msub share.
// munder uses this when movablelimits is set.
nsresult
nsMathMLmsubFrame::PlaceSubScript (nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
PRBool aPlaceOrigin,
nsHTMLReflowMetrics& aDesiredSize,
nsMathMLContainerFrame* aFrame,
nscoord aUserSubScriptShift,
nscoord aScriptSpace)
{
// force the scriptSpace to be atleast 1 pixel
aScriptSpace = NS_MAX(nsPresContext::CSSPixelsToAppUnits(1), aScriptSpace);
////////////////////////////////////
// Get the children's desired sizes
nsBoundingMetrics bmBase, bmSubScript;
nsHTMLReflowMetrics baseSize;
nsHTMLReflowMetrics subScriptSize;
nsIFrame* baseFrame = aFrame->GetFirstChild(nsnull);
nsIFrame* subScriptFrame = nsnull;
if (baseFrame)
subScriptFrame = baseFrame->GetNextSibling();
if (!baseFrame || !subScriptFrame || subScriptFrame->GetNextSibling()) {
// report an error, encourage people to get their markups in order
return aFrame->ReflowError(aRenderingContext, aDesiredSize);
}
GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
GetReflowAndBoundingMetricsFor(subScriptFrame, subScriptSize, bmSubScript);
// get the subdrop from the subscript font
nscoord subDrop;
GetSubDropFromChild(subScriptFrame, subDrop);
// parameter v, Rule 18a, App. G, TeXbook
nscoord minSubScriptShift = bmBase.descent + subDrop;
//////////////////
// Place Children
// get min subscript shift limit from x-height
// = h(x) - 4/5 * sigma_5, Rule 18b, App. G, TeXbook
nscoord xHeight = 0;
nsRefPtr<nsFontMetrics> fm;
nsLayoutUtils::GetFontMetricsForFrame(baseFrame, getter_AddRefs(fm));
xHeight = fm->XHeight();
nscoord minShiftFromXHeight = (nscoord)
(bmSubScript.ascent - (4.0f/5.0f) * xHeight);
// subScriptShift
// = minimum amount to shift the subscript down set by user or from the font
// = sub1 in TeX
// = subscriptshift attribute * x-height
nscoord subScriptShift, dummy;
// get subScriptShift default from font
GetSubScriptShifts (fm, subScriptShift, dummy);
subScriptShift =
NS_MAX(subScriptShift, aUserSubScriptShift);
// get actual subscriptshift to be used
// Rule 18b, App. G, TeXbook
nscoord actualSubScriptShift =
NS_MAX(minSubScriptShift,NS_MAX(subScriptShift,minShiftFromXHeight));
// get bounding box for base + subscript
nsBoundingMetrics boundingMetrics;
boundingMetrics.ascent =
NS_MAX(bmBase.ascent, bmSubScript.ascent - actualSubScriptShift);
boundingMetrics.descent =
NS_MAX(bmBase.descent, bmSubScript.descent + actualSubScriptShift);
// add aScriptSpace to the subscript's width
boundingMetrics.width = bmBase.width + bmSubScript.width + aScriptSpace;
boundingMetrics.leftBearing = bmBase.leftBearing;
boundingMetrics.rightBearing = NS_MAX(bmBase.rightBearing, bmBase.width +
NS_MAX(bmSubScript.width + aScriptSpace, bmSubScript.rightBearing));
aFrame->SetBoundingMetrics (boundingMetrics);
// reflow metrics
aDesiredSize.ascent =
NS_MAX(baseSize.ascent, subScriptSize.ascent - actualSubScriptShift);
aDesiredSize.height = aDesiredSize.ascent +
NS_MAX(baseSize.height - baseSize.ascent,
subScriptSize.height - subScriptSize.ascent + actualSubScriptShift);
aDesiredSize.width = boundingMetrics.width;
aDesiredSize.mBoundingMetrics = boundingMetrics;
aFrame->SetReference(nsPoint(0, aDesiredSize.ascent));
if (aPlaceOrigin) {
nscoord dx, dy;
// now place the base ...
dx = 0; dy = aDesiredSize.ascent - baseSize.ascent;
FinishReflowChild (baseFrame, aPresContext, nsnull, baseSize, dx, dy, 0);
// ... and subscript
dx = bmBase.width;
dy = aDesiredSize.ascent - (subScriptSize.ascent - actualSubScriptShift);
FinishReflowChild (subScriptFrame, aPresContext, nsnull, subScriptSize, dx, dy, 0);
}
return NS_OK;
}