gecko-dev/layout/mathml/nsMathMLChar.h

274 строки
9.6 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/. */
#ifndef nsMathMLChar_h___
#define nsMathMLChar_h___
#include "nsMathMLOperators.h"
#include "nsMathMLFrame.h"
class nsGlyphTable;
// Hints for Stretch() to indicate criteria for stretching
enum {
// Don't stretch
NS_STRETCH_NONE = 0x00,
// Variable size stretches
NS_STRETCH_VARIABLE_MASK = 0x0F,
NS_STRETCH_NORMAL = 0x01, // try to stretch to requested size
NS_STRETCH_NEARER = 0x02, // stretch very close to requested size
NS_STRETCH_SMALLER = 0x04, // don't stretch more than requested size
NS_STRETCH_LARGER = 0x08, // don't stretch less than requested size
// A largeop in displaystyle
NS_STRETCH_LARGEOP = 0x10,
NS_STRETCH_INTEGRAL = 0x20,
// Intended for internal use:
// Find the widest metrics that might be returned from a vertical stretch
NS_STRETCH_MAXWIDTH = 0x40
};
// A single glyph in our internal representation is characterized by a 'code@font'
// pair. The 'code' is interpreted as a Unicode point or as the direct glyph index
// (depending on the type of nsGlyphTable where this comes from). The 'font' is a
// numeric identifier given to the font to which the glyph belongs.
struct nsGlyphCode {
PRUnichar code[2];
PRInt32 font;
PRInt32 Length() { return (code[1] == PRUnichar('\0') ? 1 : 2); }
bool Exists() const
{
return (code[0] != 0);
}
bool operator==(const nsGlyphCode& other) const
{
return (other.code[0] == code[0] && other.code[1] == code[1] &&
other.font == font);
}
bool operator!=(const nsGlyphCode& other) const
{
return ! operator==(other);
}
};
// Class used to handle stretchy symbols (accent, delimiter and boundary symbols).
// There are composite characters that need to be built recursively from other
// characters. Since these are rare we use a light-weight mechanism to handle
// them. Specifically, as need arises we append a singly-linked list of child
// chars with their mParent pointing to the first element in the list, except in
// the originating first element itself where it points to null. mSibling points
// to the next element in the list. Since the originating first element is the
// parent of the others, we call it the "root" char of the list. Testing !mParent
// tells whether you are that "root" during the recursion. The parent delegates
// most of the tasks to the children.
class nsMathMLChar
{
public:
// constructor and destructor
nsMathMLChar(nsMathMLChar* aParent = nullptr) {
MOZ_COUNT_CTOR(nsMathMLChar);
mStyleContext = nullptr;
mSibling = nullptr;
mParent = aParent;
mUnscaledAscent = 0;
mScaleX = mScaleY = 1.0;
mDrawNormal = true;
mMirrored = false;
}
~nsMathMLChar() { // not a virtual destructor: this class is not intended to be subclassed
MOZ_COUNT_DTOR(nsMathMLChar);
// there is only one style context owned by the "root" char
// and it may be used by child chars as well
if (!mParent && mStyleContext) { // only the "root" need to release it
mStyleContext->Release();
}
if (mSibling) {
delete mSibling;
}
}
nsresult
Display(nsDisplayListBuilder* aBuilder,
nsIFrame* aForFrame,
const nsDisplayListSet& aLists,
PRUint32 aIndex,
const nsRect* aSelectedRect = nullptr);
void PaintForeground(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsPoint aPt,
bool aIsSelected);
// This is the method called to ask the char to stretch itself.
// @param aContainerSize - IN - suggested size for the stretched char
// @param aDesiredStretchSize - OUT - the size that the char wants
nsresult
Stretch(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsStretchDirection aStretchDirection,
const nsBoundingMetrics& aContainerSize,
nsBoundingMetrics& aDesiredStretchSize,
PRUint32 aStretchHint,
bool aRTL);
void
SetData(nsPresContext* aPresContext,
nsString& aData);
void
GetData(nsString& aData) {
aData = mData;
}
PRInt32
Length() {
return mData.Length();
}
nsStretchDirection
GetStretchDirection() {
return mDirection;
}
// Sometimes we only want to pass the data to another routine,
// this function helps to avoid copying
const PRUnichar*
get() {
return mData.get();
}
void
GetRect(nsRect& aRect) {
aRect = mRect;
}
void
SetRect(const nsRect& aRect) {
mRect = aRect;
// shift the orgins of child chars if any
if (!mParent && mSibling) { // only a "root" having child chars can enter here
for (nsMathMLChar* child = mSibling; child; child = child->mSibling) {
nsRect rect;
child->GetRect(rect);
rect.MoveBy(mRect.x, mRect.y);
child->SetRect(rect);
}
}
}
// Get the maximum width that the character might have after a vertical
// Stretch().
//
// @param aStretchHint can be the value that will be passed to Stretch().
// It is used to determine whether the operator is stretchy or a largeop.
// @param aMaxSize is the value of the "maxsize" attribute.
// @param aMaxSizeIsAbsolute indicates whether the aMaxSize is an absolute
// value in app units (true) or a multiplier of the base size (false).
nscoord
GetMaxWidth(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
PRUint32 aStretchHint = NS_STRETCH_NORMAL,
float aMaxSize = NS_MATHML_OPERATOR_SIZE_INFINITY,
// Perhaps just nsOperatorFlags aFlags.
// But need DisplayStyle for largeOp,
// or remove the largeop bit from flags.
bool aMaxSizeIsAbsolute = false);
// Metrics that _exactly_ enclose the char. The char *must* have *already*
// being stretched before you can call the GetBoundingMetrics() method.
// IMPORTANT: since chars have their own style contexts, and may be rendered
// with glyphs that are not in the parent font, just calling the default
// aRenderingContext.GetBoundingMetrics(aChar) can give incorrect results.
void
GetBoundingMetrics(nsBoundingMetrics& aBoundingMetrics) {
aBoundingMetrics = mBoundingMetrics;
}
void
SetBoundingMetrics(nsBoundingMetrics& aBoundingMetrics) {
mBoundingMetrics = aBoundingMetrics;
}
// Hooks to access the extra leaf style contexts given to the MathMLChars.
// They provide an interface to make them accessible to the Style System via
// the Get/Set AdditionalStyleContext() APIs. Owners of MathMLChars
// should honor these APIs.
nsStyleContext* GetStyleContext() const;
void SetStyleContext(nsStyleContext* aStyleContext);
protected:
friend class nsGlyphTable;
nsString mData;
// support for handling composite stretchy chars like TeX over/under braces
nsMathMLChar* mSibling;
nsMathMLChar* mParent;
private:
nsRect mRect;
nsStretchDirection mDirection;
nsBoundingMetrics mBoundingMetrics;
nsStyleContext* mStyleContext;
nsGlyphTable* mGlyphTable;
nsGlyphCode mGlyph;
// mFamily is non-empty when the family for the current size is different
// from the family in the nsStyleContext.
nsString mFamily;
// mUnscaledAscent is the actual ascent of the char.
nscoord mUnscaledAscent;
// mScaleX, mScaleY are the factors by which we scale the char.
float mScaleX, mScaleY;
// mDrawNormal indicates whether we use special glyphs or not.
bool mDrawNormal;
// mMirrored indicates whether the character is mirrored.
bool mMirrored;
class StretchEnumContext;
friend class StretchEnumContext;
// helper methods
nsresult
StretchInternal(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsStretchDirection& aStretchDirection,
const nsBoundingMetrics& aContainerSize,
nsBoundingMetrics& aDesiredStretchSize,
PRUint32 aStretchHint,
float aMaxSize = NS_MATHML_OPERATOR_SIZE_INFINITY,
bool aMaxSizeIsAbsolute = false);
nsresult
ComposeChildren(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsGlyphTable* aGlyphTable,
nscoord aTargetSize,
nsBoundingMetrics& aCompositeSize,
PRUint32 aStretchHint);
nsresult
PaintVertically(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsFont& aFont,
nsStyleContext* aStyleContext,
nsGlyphTable* aGlyphTable,
nsRect& aRect);
nsresult
PaintHorizontally(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsFont& aFont,
nsStyleContext* aStyleContext,
nsGlyphTable* aGlyphTable,
nsRect& aRect);
void
ApplyTransforms(nsRenderingContext& aRenderingContext, nsRect &r);
};
#endif /* nsMathMLChar_h___ */