gecko/layout/mathml/nsMathMLmsqrtFrame.cpp

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/* -*- 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>
* Vilya Harvey <vilya@nag.co.uk>
* Shyjan Mahamud <mahamud@cs.cmu.edu>
* Karl Tomlinson <karlt+@karlt.net>, Mozilla Corporation
*
* 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 ***** */
#include "nsCOMPtr.h"
#include "nsFrame.h"
#include "nsPresContext.h"
#include "nsStyleContext.h"
#include "nsStyleConsts.h"
#include "nsIRenderingContext.h"
#include "nsIFontMetrics.h"
#include "nsMathMLmsqrtFrame.h"
//
// <msqrt> and <mroot> -- form a radical - implementation
//
//NOTE:
// The code assumes that TeX fonts are picked.
// There is no fall-back to draw the branches of the sqrt explicitly
// in the case where TeX fonts are not there. In general, there are no
// fall-back(s) in MathML when some (freely-downloadable) fonts are missing.
// Otherwise, this will add much work and unnecessary complexity to the core
// MathML engine. Assuming that authors have the free fonts is part of the
// deal. We are not responsible for cases of misconfigurations out there.
// additional style context to be used by our MathMLChar.
#define NS_SQR_CHAR_STYLE_CONTEXT_INDEX 0
static const PRUnichar kSqrChar = PRUnichar(0x221A);
nsIFrame*
NS_NewMathMLmsqrtFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
{
return new (aPresShell) nsMathMLmsqrtFrame(aContext);
}
nsMathMLmsqrtFrame::nsMathMLmsqrtFrame(nsStyleContext* aContext) :
nsMathMLContainerFrame(aContext),
mSqrChar(),
mBarRect()
{
}
nsMathMLmsqrtFrame::~nsMathMLmsqrtFrame()
{
}
NS_IMETHODIMP
nsMathMLmsqrtFrame::Init(nsIContent* aContent,
nsIFrame* aParent,
nsIFrame* aPrevInFlow)
{
nsresult rv = nsMathMLContainerFrame::Init(aContent, aParent, aPrevInFlow);
nsPresContext *presContext = PresContext();
// No need to tract the style context given to our MathML char.
// The Style System will use Get/SetAdditionalStyleContext() to keep it
// up-to-date if dynamic changes arise.
nsAutoString sqrChar; sqrChar.Assign(kSqrChar);
mSqrChar.SetData(presContext, sqrChar);
ResolveMathMLCharStyle(presContext, mContent, mStyleContext, &mSqrChar, PR_TRUE);
return rv;
}
NS_IMETHODIMP
nsMathMLmsqrtFrame::InheritAutomaticData(nsIFrame* aParent)
{
// let the base class get the default from our parent
nsMathMLContainerFrame::InheritAutomaticData(aParent);
mPresentationData.flags |= NS_MATHML_STRETCH_ALL_CHILDREN_VERTICALLY;
return NS_OK;
}
NS_IMETHODIMP
nsMathMLmsqrtFrame::TransmitAutomaticData()
{
// 1. The REC says:
// The <msqrt> element leaves both attributes [displaystyle and scriptlevel]
// unchanged within all its arguments.
// 2. The TeXBook (Ch 17. p.141) says that \sqrt is cramped
UpdatePresentationDataFromChildAt(0, -1,
NS_MATHML_COMPRESSED,
NS_MATHML_COMPRESSED);
return NS_OK;
}
NS_IMETHODIMP
nsMathMLmsqrtFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
const nsRect& aDirtyRect,
const nsDisplayListSet& aLists)
{
/////////////
// paint the content we are square-rooting
nsresult rv = nsMathMLContainerFrame::BuildDisplayList(aBuilder, aDirtyRect, aLists);
NS_ENSURE_SUCCESS(rv, rv);
/////////////
// paint the sqrt symbol
if (!NS_MATHML_HAS_ERROR(mPresentationData.flags)) {
rv = mSqrChar.Display(aBuilder, this, aLists);
NS_ENSURE_SUCCESS(rv, rv);
rv = DisplayBar(aBuilder, this, mBarRect, aLists);
NS_ENSURE_SUCCESS(rv, rv);
#if defined(NS_DEBUG) && defined(SHOW_BOUNDING_BOX)
// for visual debug
nsRect rect;
mSqrChar.GetRect(rect);
nsBoundingMetrics bm;
mSqrChar.GetBoundingMetrics(bm);
rv = DisplayBoundingMetrics(aBuilder, this, rect.TopLeft(), bm, aLists);
#endif
}
return rv;
}
/* virtual */ nsresult
nsMathMLmsqrtFrame::Place(nsIRenderingContext& aRenderingContext,
PRBool aPlaceOrigin,
nsHTMLReflowMetrics& aDesiredSize)
{
///////////////
// Measure the size of our content using the base class to format like an
// inferred mrow.
nsHTMLReflowMetrics baseSize;
nsresult rv =
nsMathMLContainerFrame::Place(aRenderingContext, PR_FALSE, baseSize);
if (NS_MATHML_HAS_ERROR(mPresentationData.flags) || NS_FAILED(rv)) {
DidReflowChildren(GetFirstChild(nsnull));
return rv;
}
nsBoundingMetrics bmSqr, bmBase;
bmBase = baseSize.mBoundingMetrics;
////////////
// Prepare the radical symbol and the overline bar
aRenderingContext.SetFont(GetStyleFont()->mFont, nsnull,
PresContext()->GetUserFontSet());
nsCOMPtr<nsIFontMetrics> fm;
aRenderingContext.GetFontMetrics(*getter_AddRefs(fm));
// For radical glyphs from TeX fonts and some of the radical glyphs from
// Mathematica fonts, the thickness of the overline can be obtained from the
// ascent of the glyph. Most fonts however have radical glyphs above the
// baseline so no assumption can be made about the meaning of the ascent.
nscoord ruleThickness, leading, em;
GetRuleThickness(aRenderingContext, fm, ruleThickness);
nsBoundingMetrics bmOne;
aRenderingContext.GetBoundingMetrics(NS_LITERAL_STRING("1").get(), 1, bmOne);
// get the leading to be left at the top of the resulting frame
// this seems more reliable than using fm->GetLeading() on suspicious fonts
GetEmHeight(fm, em);
leading = nscoord(0.2f * em);
// Rule 11, App. G, TeXbook
// psi = clearance between rule and content
nscoord phi = 0, psi = 0;
if (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags))
fm->GetXHeight(phi);
else
phi = ruleThickness;
psi = ruleThickness + phi/4;
// built-in: adjust clearance psi to emulate \mathstrut using '1' (TexBook, p.131)
if (bmOne.ascent > bmBase.ascent)
psi += bmOne.ascent - bmBase.ascent;
// make sure that the rule appears on the screen
nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
if (ruleThickness < onePixel) {
ruleThickness = onePixel;
}
// adjust clearance psi to get an exact number of pixels -- this
// gives a nicer & uniform look on stacked radicals (bug 130282)
nscoord delta = psi % onePixel;
if (delta)
psi += onePixel - delta; // round up
// Stretch the radical symbol to the appropriate height if it is not big enough.
nsBoundingMetrics contSize = bmBase;
contSize.ascent = ruleThickness;
contSize.descent = bmBase.ascent + bmBase.descent + psi;
// height(radical) should be >= height(base) + psi + ruleThickness
nsBoundingMetrics radicalSize;
mSqrChar.Stretch(PresContext(), aRenderingContext,
NS_STRETCH_DIRECTION_VERTICAL,
contSize, radicalSize,
NS_STRETCH_LARGER);
// radicalSize have changed at this point, and should match with
// the bounding metrics of the char
mSqrChar.GetBoundingMetrics(bmSqr);
nscoord dx = 0, dy = 0;
// place the radical symbol and the radical bar
dy = leading; // leave a leading at the top
mSqrChar.SetRect(nsRect(dx, dy, bmSqr.width, bmSqr.ascent + bmSqr.descent));
dx = bmSqr.width;
mBarRect.SetRect(dx, dy, bmBase.width, ruleThickness);
// Update the desired size for the container.
// the baseline will be that of the base.
mBoundingMetrics.ascent = bmBase.ascent + psi + ruleThickness;
mBoundingMetrics.descent =
PR_MAX(bmBase.descent,
(bmSqr.ascent + bmSqr.descent - mBoundingMetrics.ascent));
mBoundingMetrics.width = bmSqr.width + bmBase.width;
mBoundingMetrics.leftBearing = bmSqr.leftBearing;
mBoundingMetrics.rightBearing = bmSqr.width +
PR_MAX(bmBase.width, bmBase.rightBearing); // take also care of the rule
aDesiredSize.ascent = mBoundingMetrics.ascent + leading;
aDesiredSize.height = aDesiredSize.ascent +
PR_MAX(baseSize.height - baseSize.ascent,
mBoundingMetrics.descent + ruleThickness);
aDesiredSize.width = mBoundingMetrics.width;
aDesiredSize.mBoundingMetrics = mBoundingMetrics;
mReference.x = 0;
mReference.y = aDesiredSize.ascent;
if (aPlaceOrigin) {
//////////////////
// Finish reflowing child frames, positioning their origins so as to leave
// room for the sqrt char and the overline bar.
PositionRowChildFrames(radicalSize.width, aDesiredSize.ascent);
}
return NS_OK;
}
/* virtual */ nscoord
nsMathMLmsqrtFrame::GetIntrinsicWidth(nsIRenderingContext* aRenderingContext)
{
// The child frames form an mrow
nscoord width = nsMathMLContainerFrame::GetIntrinsicWidth(aRenderingContext);
// Add the width of the radical symbol
width += mSqrChar.GetMaxWidth(PresContext(), *aRenderingContext);
return width;
}
/* virtual */ nsresult
nsMathMLmsqrtFrame::MeasureChildFrames(nsIRenderingContext& aRenderingContext,
nsHTMLReflowMetrics& aDesiredSize)
{
return nsMathMLContainerFrame::Place(aRenderingContext, PR_FALSE,
aDesiredSize);
}
nscoord
nsMathMLmsqrtFrame::FixInterFrameSpacing(nsHTMLReflowMetrics& aDesiredSize)
{
nscoord gap = nsMathMLContainerFrame::FixInterFrameSpacing(aDesiredSize);
if (!gap) return 0;
nsRect rect;
mSqrChar.GetRect(rect);
rect.MoveBy(gap, 0);
mSqrChar.SetRect(rect);
mBarRect.MoveBy(gap, 0);
return gap;
}
// ----------------------
// the Style System will use these to pass the proper style context to our MathMLChar
nsStyleContext*
nsMathMLmsqrtFrame::GetAdditionalStyleContext(PRInt32 aIndex) const
{
switch (aIndex) {
case NS_SQR_CHAR_STYLE_CONTEXT_INDEX:
return mSqrChar.GetStyleContext();
break;
default:
return nsnull;
}
}
void
nsMathMLmsqrtFrame::SetAdditionalStyleContext(PRInt32 aIndex,
nsStyleContext* aStyleContext)
{
switch (aIndex) {
case NS_SQR_CHAR_STYLE_CONTEXT_INDEX:
mSqrChar.SetStyleContext(aStyleContext);
break;
}
}