gecko-dev/layout/mathml/nsMathMLFrame.cpp

354 lines
12 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "nsMathMLFrame.h"
#include "nsNameSpaceManager.h"
#include "nsMathMLChar.h"
#include "nsCSSPseudoElements.h"
#include "nsMathMLElement.h"
// used to map attributes into CSS rules
#include "nsStyleSet.h"
#include "nsAutoPtr.h"
#include "nsDisplayList.h"
#include "nsRenderingContext.h"
eMathMLFrameType
nsMathMLFrame::GetMathMLFrameType()
{
// see if it is an embellished operator (mapped to 'Op' in TeX)
if (mEmbellishData.coreFrame)
return GetMathMLFrameTypeFor(mEmbellishData.coreFrame);
// if it has a prescribed base, fetch the type from there
if (mPresentationData.baseFrame)
return GetMathMLFrameTypeFor(mPresentationData.baseFrame);
// everything else is treated as ordinary (mapped to 'Ord' in TeX)
return eMathMLFrameType_Ordinary;
}
NS_IMETHODIMP
nsMathMLFrame::InheritAutomaticData(nsIFrame* aParent)
{
mEmbellishData.flags = 0;
mEmbellishData.coreFrame = nullptr;
mEmbellishData.direction = NS_STRETCH_DIRECTION_UNSUPPORTED;
mEmbellishData.leadingSpace = 0;
mEmbellishData.trailingSpace = 0;
mPresentationData.flags = 0;
mPresentationData.baseFrame = nullptr;
// by default, just inherit the display of our parent
nsPresentationData parentData;
GetPresentationDataFrom(aParent, parentData);
#if defined(DEBUG) && defined(SHOW_BOUNDING_BOX)
mPresentationData.flags |= NS_MATHML_SHOW_BOUNDING_METRICS;
#endif
return NS_OK;
}
NS_IMETHODIMP
nsMathMLFrame::UpdatePresentationData(uint32_t aFlagsValues,
uint32_t aWhichFlags)
{
NS_ASSERTION(NS_MATHML_IS_COMPRESSED(aWhichFlags),
"aWhichFlags should only be compression flag");
if (NS_MATHML_IS_COMPRESSED(aWhichFlags)) {
// updating the compression flag is allowed
if (NS_MATHML_IS_COMPRESSED(aFlagsValues)) {
// 'compressed' means 'prime' style in App. G, TeXbook
mPresentationData.flags |= NS_MATHML_COMPRESSED;
}
// no else. the flag is sticky. it retains its value once it is set
}
return NS_OK;
}
// Helper to give a style context suitable for doing the stretching of
// a MathMLChar. Frame classes that use this should ensure that the
// extra leaf style contexts given to the MathMLChars are accessible to
// the Style System via the Get/Set AdditionalStyleContext() APIs.
/* static */ void
nsMathMLFrame::ResolveMathMLCharStyle(nsPresContext* aPresContext,
nsIContent* aContent,
nsStyleContext* aParentStyleContext,
nsMathMLChar* aMathMLChar)
{
nsCSSPseudoElements::Type pseudoType =
nsCSSPseudoElements::ePseudo_mozMathAnonymous; // savings
nsRefPtr<nsStyleContext> newStyleContext;
newStyleContext = aPresContext->StyleSet()->
ResolvePseudoElementStyle(aContent->AsElement(), pseudoType,
aParentStyleContext, nullptr);
aMathMLChar->SetStyleContext(newStyleContext);
}
/* static */ void
nsMathMLFrame::GetEmbellishDataFrom(nsIFrame* aFrame,
nsEmbellishData& aEmbellishData)
{
// initialize OUT params
aEmbellishData.flags = 0;
aEmbellishData.coreFrame = nullptr;
aEmbellishData.direction = NS_STRETCH_DIRECTION_UNSUPPORTED;
aEmbellishData.leadingSpace = 0;
aEmbellishData.trailingSpace = 0;
if (aFrame && aFrame->IsFrameOfType(nsIFrame::eMathML)) {
nsIMathMLFrame* mathMLFrame = do_QueryFrame(aFrame);
if (mathMLFrame) {
mathMLFrame->GetEmbellishData(aEmbellishData);
}
}
}
// helper to get the presentation data of a frame, by possibly walking up
// the frame hierarchy if we happen to be surrounded by non-MathML frames.
/* static */ void
nsMathMLFrame::GetPresentationDataFrom(nsIFrame* aFrame,
nsPresentationData& aPresentationData,
bool aClimbTree)
{
// initialize OUT params
aPresentationData.flags = 0;
aPresentationData.baseFrame = nullptr;
nsIFrame* frame = aFrame;
while (frame) {
if (frame->IsFrameOfType(nsIFrame::eMathML)) {
nsIMathMLFrame* mathMLFrame = do_QueryFrame(frame);
if (mathMLFrame) {
mathMLFrame->GetPresentationData(aPresentationData);
break;
}
}
// stop if the caller doesn't want to lookup beyond the frame
if (!aClimbTree) {
break;
}
// stop if we reach the root <math> tag
nsIContent* content = frame->GetContent();
NS_ASSERTION(content || !frame->GetParent(), // no assert for the root
"dangling frame without a content node");
if (!content)
break;
if (content->Tag() == nsGkAtoms::math) {
break;
}
frame = frame->GetParent();
}
NS_WARN_IF_FALSE(frame && frame->GetContent(),
"bad MathML markup - could not find the top <math> element");
}
/* static */ void
nsMathMLFrame::GetRuleThickness(nsRenderingContext& aRenderingContext,
nsFontMetrics* aFontMetrics,
nscoord& aRuleThickness)
{
// get the bounding metrics of the overbar char, the rendering context
// is assumed to have been set with the font of the current style context
NS_ASSERTION(aRenderingContext.FontMetrics()->Font().
Equals(aFontMetrics->Font()),
"unexpected state");
nscoord xHeight = aFontMetrics->XHeight();
char16_t overBar = 0x00AF;
nsBoundingMetrics bm = aRenderingContext.GetBoundingMetrics(&overBar, 1);
aRuleThickness = bm.ascent + bm.descent;
if (aRuleThickness <= 0 || aRuleThickness >= xHeight) {
// fall-back to the other version
GetRuleThickness(aFontMetrics, aRuleThickness);
}
}
/* static */ void
nsMathMLFrame::GetAxisHeight(nsRenderingContext& aRenderingContext,
nsFontMetrics* aFontMetrics,
nscoord& aAxisHeight)
{
// get the bounding metrics of the minus sign, the rendering context
// is assumed to have been set with the font of the current style context
NS_ASSERTION(aRenderingContext.FontMetrics()->Font().
Equals(aFontMetrics->Font()),
"unexpected state");
nscoord xHeight = aFontMetrics->XHeight();
char16_t minus = 0x2212; // not '-', but official Unicode minus sign
nsBoundingMetrics bm = aRenderingContext.GetBoundingMetrics(&minus, 1);
aAxisHeight = bm.ascent - (bm.ascent + bm.descent)/2;
if (aAxisHeight <= 0 || aAxisHeight >= xHeight) {
// fall-back to the other version
GetAxisHeight(aFontMetrics, aAxisHeight);
}
}
/* static */ nscoord
nsMathMLFrame::CalcLength(nsPresContext* aPresContext,
nsStyleContext* aStyleContext,
const nsCSSValue& aCSSValue)
{
NS_ASSERTION(aCSSValue.IsLengthUnit(), "not a length unit");
if (aCSSValue.IsFixedLengthUnit()) {
return aCSSValue.GetFixedLength(aPresContext);
}
if (aCSSValue.IsPixelLengthUnit()) {
return aCSSValue.GetPixelLength();
}
nsCSSUnit unit = aCSSValue.GetUnit();
if (eCSSUnit_EM == unit) {
const nsStyleFont* font = aStyleContext->StyleFont();
return NSToCoordRound(aCSSValue.GetFloatValue() * (float)font->mFont.size);
}
else if (eCSSUnit_XHeight == unit) {
nsRefPtr<nsFontMetrics> fm;
nsLayoutUtils::GetFontMetricsForStyleContext(aStyleContext,
getter_AddRefs(fm));
nscoord xHeight = fm->XHeight();
return NSToCoordRound(aCSSValue.GetFloatValue() * (float)xHeight);
}
// MathML doesn't specify other CSS units such as rem or ch
NS_ERROR("Unsupported unit");
return 0;
}
/* static */ void
nsMathMLFrame::ParseNumericValue(const nsString& aString,
nscoord* aLengthValue,
uint32_t aFlags,
nsPresContext* aPresContext,
nsStyleContext* aStyleContext)
{
nsCSSValue cssValue;
if (!nsMathMLElement::ParseNumericValue(aString, cssValue, aFlags,
aPresContext->Document())) {
// Invalid attribute value. aLengthValue remains unchanged, so the default
// length value is used.
return;
}
nsCSSUnit unit = cssValue.GetUnit();
if (unit == eCSSUnit_Percent || unit == eCSSUnit_Number) {
// Relative units. A multiple of the default length value is used.
*aLengthValue = NSToCoordRound(*aLengthValue * (unit == eCSSUnit_Percent ?
cssValue.GetPercentValue() :
cssValue.GetFloatValue()));
return;
}
// Absolute units.
*aLengthValue = CalcLength(aPresContext, aStyleContext, cssValue);
}
// ================
// Utils to map attributes into CSS rules (work-around to bug 69409 which
// is not scheduled to be fixed anytime soon)
//
struct
nsCSSMapping {
int32_t compatibility;
const nsIAtom* attrAtom;
const char* cssProperty;
};
#if defined(DEBUG) && defined(SHOW_BOUNDING_BOX)
class nsDisplayMathMLBoundingMetrics : public nsDisplayItem {
public:
nsDisplayMathMLBoundingMetrics(nsDisplayListBuilder* aBuilder,
nsIFrame* aFrame, const nsRect& aRect)
: nsDisplayItem(aBuilder, aFrame), mRect(aRect) {
MOZ_COUNT_CTOR(nsDisplayMathMLBoundingMetrics);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayMathMLBoundingMetrics() {
MOZ_COUNT_DTOR(nsDisplayMathMLBoundingMetrics);
}
#endif
virtual void Paint(nsDisplayListBuilder* aBuilder,
nsRenderingContext* aCtx) MOZ_OVERRIDE;
NS_DISPLAY_DECL_NAME("MathMLBoundingMetrics", TYPE_MATHML_BOUNDING_METRICS)
private:
nsRect mRect;
};
void nsDisplayMathMLBoundingMetrics::Paint(nsDisplayListBuilder* aBuilder,
nsRenderingContext* aCtx)
{
aCtx->SetColor(NS_RGB(0,0,255));
aCtx->DrawRect(mRect + ToReferenceFrame());
}
nsresult
nsMathMLFrame::DisplayBoundingMetrics(nsDisplayListBuilder* aBuilder,
nsIFrame* aFrame, const nsPoint& aPt,
const nsBoundingMetrics& aMetrics,
const nsDisplayListSet& aLists) {
if (!NS_MATHML_PAINT_BOUNDING_METRICS(mPresentationData.flags))
return NS_OK;
nscoord x = aPt.x + aMetrics.leftBearing;
nscoord y = aPt.y - aMetrics.ascent;
nscoord w = aMetrics.rightBearing - aMetrics.leftBearing;
nscoord h = aMetrics.ascent + aMetrics.descent;
return aLists.Content()->AppendNewToTop(new (aBuilder)
nsDisplayMathMLBoundingMetrics(aBuilder, this, nsRect(x,y,w,h)));
}
#endif
class nsDisplayMathMLBar : public nsDisplayItem {
public:
nsDisplayMathMLBar(nsDisplayListBuilder* aBuilder,
nsIFrame* aFrame, const nsRect& aRect)
: nsDisplayItem(aBuilder, aFrame), mRect(aRect) {
MOZ_COUNT_CTOR(nsDisplayMathMLBar);
}
#ifdef NS_BUILD_REFCNT_LOGGING
virtual ~nsDisplayMathMLBar() {
MOZ_COUNT_DTOR(nsDisplayMathMLBar);
}
#endif
virtual void Paint(nsDisplayListBuilder* aBuilder,
nsRenderingContext* aCtx) MOZ_OVERRIDE;
NS_DISPLAY_DECL_NAME("MathMLBar", TYPE_MATHML_BAR)
private:
nsRect mRect;
};
void nsDisplayMathMLBar::Paint(nsDisplayListBuilder* aBuilder,
nsRenderingContext* aCtx)
{
// paint the bar with the current text color
aCtx->SetColor(mFrame->GetVisitedDependentColor(eCSSProperty_color));
aCtx->FillRect(mRect + ToReferenceFrame());
}
void
nsMathMLFrame::DisplayBar(nsDisplayListBuilder* aBuilder,
nsIFrame* aFrame, const nsRect& aRect,
const nsDisplayListSet& aLists) {
if (!aFrame->StyleVisibility()->IsVisible() || aRect.IsEmpty())
return;
aLists.Content()->AppendNewToTop(new (aBuilder)
nsDisplayMathMLBar(aBuilder, aFrame, aRect));
}