419 lines
15 KiB
C++
419 lines
15 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "nsMathMLmrootFrame.h"
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#include "nsPresContext.h"
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#include "nsRenderingContext.h"
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#include <algorithm>
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#include "gfxMathTable.h"
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using namespace mozilla;
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//
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// <mroot> -- form a radical - implementation
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//
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// additional style context to be used by our MathMLChar.
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#define NS_SQR_CHAR_STYLE_CONTEXT_INDEX 0
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static const char16_t kSqrChar = char16_t(0x221A);
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nsIFrame*
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NS_NewMathMLmrootFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
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{
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return new (aPresShell) nsMathMLmrootFrame(aContext);
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}
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NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmrootFrame)
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nsMathMLmrootFrame::nsMathMLmrootFrame(nsStyleContext* aContext) :
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nsMathMLContainerFrame(aContext),
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mSqrChar(),
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mBarRect()
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{
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}
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nsMathMLmrootFrame::~nsMathMLmrootFrame()
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{
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}
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void
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nsMathMLmrootFrame::Init(nsIContent* aContent,
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nsContainerFrame* aParent,
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nsIFrame* aPrevInFlow)
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{
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nsMathMLContainerFrame::Init(aContent, aParent, aPrevInFlow);
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nsPresContext *presContext = PresContext();
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// No need to track the style context given to our MathML char.
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// The Style System will use Get/SetAdditionalStyleContext() to keep it
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// up-to-date if dynamic changes arise.
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nsAutoString sqrChar; sqrChar.Assign(kSqrChar);
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mSqrChar.SetData(sqrChar);
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ResolveMathMLCharStyle(presContext, mContent, mStyleContext, &mSqrChar);
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}
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NS_IMETHODIMP
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nsMathMLmrootFrame::TransmitAutomaticData()
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{
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// 1. The REC says:
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// The <mroot> element increments scriptlevel by 2, and sets displaystyle to
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// "false", within index, but leaves both attributes unchanged within base.
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// 2. The TeXbook (Ch 17. p.141) says \sqrt is compressed
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UpdatePresentationDataFromChildAt(1, 1,
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NS_MATHML_COMPRESSED,
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NS_MATHML_COMPRESSED);
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UpdatePresentationDataFromChildAt(0, 0,
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NS_MATHML_COMPRESSED, NS_MATHML_COMPRESSED);
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PropagateFrameFlagFor(mFrames.LastChild(),
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NS_FRAME_MATHML_SCRIPT_DESCENDANT);
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return NS_OK;
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}
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void
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nsMathMLmrootFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
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const nsDisplayListSet& aLists)
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{
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/////////////
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// paint the content we are square-rooting
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nsMathMLContainerFrame::BuildDisplayList(aBuilder, aLists);
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/////////////
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// paint the sqrt symbol
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if (!NS_MATHML_HAS_ERROR(mPresentationData.flags)) {
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mSqrChar.Display(aBuilder, this, aLists, 0);
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DisplayBar(aBuilder, this, mBarRect, aLists);
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#if defined(DEBUG) && defined(SHOW_BOUNDING_BOX)
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// for visual debug
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nsRect rect;
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mSqrChar.GetRect(rect);
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nsBoundingMetrics bm;
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mSqrChar.GetBoundingMetrics(bm);
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DisplayBoundingMetrics(aBuilder, this, rect.TopLeft(), bm, aLists);
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#endif
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}
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}
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void
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nsMathMLmrootFrame::GetRadicalXOffsets(nscoord aIndexWidth, nscoord aSqrWidth,
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nsFontMetrics* aFontMetrics,
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nscoord* aIndexOffset,
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nscoord* aSqrOffset)
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{
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// The index is tucked in closer to the radical while making sure
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// that the kern does not make the index and radical collide
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nscoord dxIndex, dxSqr;
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nscoord xHeight = aFontMetrics->XHeight();
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nscoord indexRadicalKern = NSToCoordRound(1.35f * xHeight);
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nscoord oneDevPixel = aFontMetrics->AppUnitsPerDevPixel();
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gfxFont* mathFont = aFontMetrics->GetThebesFontGroup()->GetFirstMathFont();
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if (mathFont) {
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indexRadicalKern =
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mathFont->MathTable()->Constant(gfxMathTable::RadicalKernAfterDegree,
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oneDevPixel);
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indexRadicalKern = -indexRadicalKern;
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}
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if (indexRadicalKern > aIndexWidth) {
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dxIndex = indexRadicalKern - aIndexWidth;
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dxSqr = 0;
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}
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else {
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dxIndex = 0;
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dxSqr = aIndexWidth - indexRadicalKern;
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}
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if (mathFont) {
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// add some kern before the radical index
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nscoord indexRadicalKernBefore = 0;
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indexRadicalKernBefore =
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mathFont->MathTable()->Constant(gfxMathTable::RadicalKernBeforeDegree,
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oneDevPixel);
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dxIndex += indexRadicalKernBefore;
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dxSqr += indexRadicalKernBefore;
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} else {
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// avoid collision by leaving a minimum space between index and radical
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nscoord minimumClearance = aSqrWidth / 2;
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if (dxIndex + aIndexWidth + minimumClearance > dxSqr + aSqrWidth) {
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if (aIndexWidth + minimumClearance < aSqrWidth) {
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dxIndex = aSqrWidth - (aIndexWidth + minimumClearance);
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dxSqr = 0;
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}
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else {
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dxIndex = 0;
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dxSqr = (aIndexWidth + minimumClearance) - aSqrWidth;
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}
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}
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}
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if (aIndexOffset)
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*aIndexOffset = dxIndex;
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if (aSqrOffset)
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*aSqrOffset = dxSqr;
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}
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void
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nsMathMLmrootFrame::Reflow(nsPresContext* aPresContext,
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ReflowOutput& aDesiredSize,
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const ReflowInput& aReflowInput,
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nsReflowStatus& aStatus)
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{
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MarkInReflow();
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nsReflowStatus childStatus;
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mPresentationData.flags &= ~NS_MATHML_ERROR;
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aDesiredSize.ClearSize();
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aDesiredSize.SetBlockStartAscent(0);
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nsBoundingMetrics bmSqr, bmBase, bmIndex;
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DrawTarget* drawTarget = aReflowInput.mRenderingContext->GetDrawTarget();
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//////////////////
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// Reflow Children
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int32_t count = 0;
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nsIFrame* baseFrame = nullptr;
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nsIFrame* indexFrame = nullptr;
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ReflowOutput baseSize(aReflowInput);
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ReflowOutput indexSize(aReflowInput);
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nsIFrame* childFrame = mFrames.FirstChild();
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while (childFrame) {
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// ask our children to compute their bounding metrics
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ReflowOutput childDesiredSize(aReflowInput,
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aDesiredSize.mFlags
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| NS_REFLOW_CALC_BOUNDING_METRICS);
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WritingMode wm = childFrame->GetWritingMode();
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LogicalSize availSize = aReflowInput.ComputedSize(wm);
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availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
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ReflowInput childReflowInput(aPresContext, aReflowInput,
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childFrame, availSize);
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ReflowChild(childFrame, aPresContext,
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childDesiredSize, childReflowInput, childStatus);
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//NS_ASSERTION(NS_FRAME_IS_COMPLETE(childStatus), "bad status");
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if (0 == count) {
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// base
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baseFrame = childFrame;
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baseSize = childDesiredSize;
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bmBase = childDesiredSize.mBoundingMetrics;
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}
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else if (1 == count) {
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// index
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indexFrame = childFrame;
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indexSize = childDesiredSize;
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bmIndex = childDesiredSize.mBoundingMetrics;
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}
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count++;
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childFrame = childFrame->GetNextSibling();
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}
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if (2 != count) {
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// report an error, encourage people to get their markups in order
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ReportChildCountError();
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ReflowError(drawTarget, aDesiredSize);
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aStatus = NS_FRAME_COMPLETE;
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NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
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// Call DidReflow() for the child frames we successfully did reflow.
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DidReflowChildren(mFrames.FirstChild(), childFrame);
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return;
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}
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////////////
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// Prepare the radical symbol and the overline bar
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float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
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RefPtr<nsFontMetrics> fm =
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nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
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nscoord ruleThickness, leading, psi;
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GetRadicalParameters(fm, StyleFont()->mMathDisplay ==
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NS_MATHML_DISPLAYSTYLE_BLOCK,
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ruleThickness, leading, psi);
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// built-in: adjust clearance psi to emulate \mathstrut using '1' (TexBook, p.131)
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char16_t one = '1';
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nsBoundingMetrics bmOne =
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nsLayoutUtils::AppUnitBoundsOfString(&one, 1, *fm, drawTarget);
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if (bmOne.ascent > bmBase.ascent)
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psi += bmOne.ascent - bmBase.ascent;
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// make sure that the rule appears on on screen
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nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
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if (ruleThickness < onePixel) {
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ruleThickness = onePixel;
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}
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// adjust clearance psi to get an exact number of pixels -- this
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// gives a nicer & uniform look on stacked radicals (bug 130282)
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nscoord delta = psi % onePixel;
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if (delta)
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psi += onePixel - delta; // round up
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// Stretch the radical symbol to the appropriate height if it is not big enough.
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nsBoundingMetrics contSize = bmBase;
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contSize.descent = bmBase.ascent + bmBase.descent + psi;
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contSize.ascent = ruleThickness;
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// height(radical) should be >= height(base) + psi + ruleThickness
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nsBoundingMetrics radicalSize;
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mSqrChar.Stretch(aPresContext, drawTarget,
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fontSizeInflation,
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NS_STRETCH_DIRECTION_VERTICAL,
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contSize, radicalSize,
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NS_STRETCH_LARGER,
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StyleVisibility()->mDirection);
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// radicalSize have changed at this point, and should match with
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// the bounding metrics of the char
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mSqrChar.GetBoundingMetrics(bmSqr);
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// Update the desired size for the container (like msqrt, index is not yet included)
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// the baseline will be that of the base.
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mBoundingMetrics.ascent = bmBase.ascent + psi + ruleThickness;
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mBoundingMetrics.descent =
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std::max(bmBase.descent,
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(bmSqr.ascent + bmSqr.descent - mBoundingMetrics.ascent));
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mBoundingMetrics.width = bmSqr.width + bmBase.width;
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mBoundingMetrics.leftBearing = bmSqr.leftBearing;
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mBoundingMetrics.rightBearing = bmSqr.width +
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std::max(bmBase.width, bmBase.rightBearing); // take also care of the rule
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aDesiredSize.SetBlockStartAscent(mBoundingMetrics.ascent + leading);
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aDesiredSize.Height() = aDesiredSize.BlockStartAscent() +
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std::max(baseSize.Height() - baseSize.BlockStartAscent(),
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mBoundingMetrics.descent + ruleThickness);
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aDesiredSize.Width() = mBoundingMetrics.width;
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/////////////
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// Re-adjust the desired size to include the index.
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// the index is raised by some fraction of the height
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// of the radical, see \mroot macro in App. B, TexBook
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float raiseIndexPercent = 0.6f;
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gfxFont* mathFont = fm->GetThebesFontGroup()->GetFirstMathFont();
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if (mathFont) {
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raiseIndexPercent = mathFont->MathTable()->
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Constant(gfxMathTable::RadicalDegreeBottomRaisePercent);
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}
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nscoord raiseIndexDelta = NSToCoordRound(raiseIndexPercent *
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(bmSqr.ascent + bmSqr.descent));
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nscoord indexRaisedAscent = mBoundingMetrics.ascent // top of radical
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- (bmSqr.ascent + bmSqr.descent) // to bottom of radical
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+ raiseIndexDelta + bmIndex.ascent + bmIndex.descent; // to top of raised index
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nscoord indexClearance = 0;
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if (mBoundingMetrics.ascent < indexRaisedAscent) {
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indexClearance =
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indexRaisedAscent - mBoundingMetrics.ascent; // excess gap introduced by a tall index
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mBoundingMetrics.ascent = indexRaisedAscent;
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nscoord descent = aDesiredSize.Height() - aDesiredSize.BlockStartAscent();
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aDesiredSize.SetBlockStartAscent(mBoundingMetrics.ascent + leading);
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aDesiredSize.Height() = aDesiredSize.BlockStartAscent() + descent;
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}
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nscoord dxIndex, dxSqr;
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GetRadicalXOffsets(bmIndex.width, bmSqr.width, fm, &dxIndex, &dxSqr);
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mBoundingMetrics.width = dxSqr + bmSqr.width + bmBase.width;
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mBoundingMetrics.leftBearing =
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std::min(dxIndex + bmIndex.leftBearing, dxSqr + bmSqr.leftBearing);
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mBoundingMetrics.rightBearing = dxSqr + bmSqr.width +
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std::max(bmBase.width, bmBase.rightBearing);
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aDesiredSize.Width() = mBoundingMetrics.width;
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aDesiredSize.mBoundingMetrics = mBoundingMetrics;
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GatherAndStoreOverflow(&aDesiredSize);
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// place the index
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nscoord dx = dxIndex;
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nscoord dy = aDesiredSize.BlockStartAscent() -
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(indexRaisedAscent + indexSize.BlockStartAscent() - bmIndex.ascent);
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FinishReflowChild(indexFrame, aPresContext, indexSize, nullptr,
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MirrorIfRTL(aDesiredSize.Width(), indexSize.Width(), dx),
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dy, 0);
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// place the radical symbol and the radical bar
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dx = dxSqr;
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dy = indexClearance + leading; // leave a leading at the top
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mSqrChar.SetRect(nsRect(MirrorIfRTL(aDesiredSize.Width(), bmSqr.width, dx),
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dy, bmSqr.width, bmSqr.ascent + bmSqr.descent));
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dx += bmSqr.width;
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mBarRect.SetRect(MirrorIfRTL(aDesiredSize.Width(), bmBase.width, dx),
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dy, bmBase.width, ruleThickness);
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// place the base
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dy = aDesiredSize.BlockStartAscent() - baseSize.BlockStartAscent();
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FinishReflowChild(baseFrame, aPresContext, baseSize, nullptr,
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MirrorIfRTL(aDesiredSize.Width(), baseSize.Width(), dx),
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dy, 0);
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mReference.x = 0;
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mReference.y = aDesiredSize.BlockStartAscent();
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aStatus = NS_FRAME_COMPLETE;
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NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
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}
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/* virtual */ void
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nsMathMLmrootFrame::GetIntrinsicISizeMetrics(nsRenderingContext* aRenderingContext, ReflowOutput& aDesiredSize)
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{
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nsIFrame* baseFrame = mFrames.FirstChild();
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nsIFrame* indexFrame = nullptr;
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if (baseFrame)
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indexFrame = baseFrame->GetNextSibling();
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if (!indexFrame || indexFrame->GetNextSibling()) {
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ReflowError(aRenderingContext->GetDrawTarget(), aDesiredSize);
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return;
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}
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float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
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nscoord baseWidth =
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nsLayoutUtils::IntrinsicForContainer(aRenderingContext, baseFrame,
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nsLayoutUtils::PREF_ISIZE);
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nscoord indexWidth =
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nsLayoutUtils::IntrinsicForContainer(aRenderingContext, indexFrame,
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nsLayoutUtils::PREF_ISIZE);
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nscoord sqrWidth = mSqrChar.GetMaxWidth(PresContext(),
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aRenderingContext->GetDrawTarget(),
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fontSizeInflation);
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nscoord dxSqr;
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RefPtr<nsFontMetrics> fm =
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nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
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GetRadicalXOffsets(indexWidth, sqrWidth, fm, nullptr, &dxSqr);
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nscoord width = dxSqr + sqrWidth + baseWidth;
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aDesiredSize.Width() = width;
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aDesiredSize.mBoundingMetrics.width = width;
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aDesiredSize.mBoundingMetrics.leftBearing = 0;
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aDesiredSize.mBoundingMetrics.rightBearing = width;
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}
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// ----------------------
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// the Style System will use these to pass the proper style context to our MathMLChar
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nsStyleContext*
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nsMathMLmrootFrame::GetAdditionalStyleContext(int32_t aIndex) const
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{
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switch (aIndex) {
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case NS_SQR_CHAR_STYLE_CONTEXT_INDEX:
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return mSqrChar.GetStyleContext();
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default:
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return nullptr;
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}
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}
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void
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nsMathMLmrootFrame::SetAdditionalStyleContext(int32_t aIndex,
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nsStyleContext* aStyleContext)
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{
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switch (aIndex) {
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case NS_SQR_CHAR_STYLE_CONTEXT_INDEX:
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mSqrChar.SetStyleContext(aStyleContext);
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break;
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}
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}
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