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nsMathMLChar.cpp
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nsMathMLChar.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>
* Shyjan Mahamud <mahamud@cs.cmu.edu>
* Karl Tomlinson <karlt+@karlt.net>, Mozilla Corporation
* Frederic Wang <fred.wang@free.fr>
*
* 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 "nsString.h"
#include "nsUnicharUtils.h"
#include "nsRenderingContext.h"
#include "gfxPlatform.h"
#include "mozilla/Preferences.h"
#include "nsISupportsPrimitives.h"
#include "nsIComponentManager.h"
#include "nsIPersistentProperties2.h"
#include "nsIServiceManager.h"
#include "nsIObserverService.h"
#include "nsIObserver.h"
#include "nsNetUtil.h"
#include "mozilla/LookAndFeel.h"
#include "nsCSSRendering.h"
#include "prprf.h" // For PR_snprintf()
#include "nsDisplayList.h"
#include "nsMathMLOperators.h"
#include "nsMathMLChar.h"
using namespace mozilla;
//#define SHOW_BORDERS 1
//#define NOISY_SEARCH 1
// -----------------------------------------------------------------------------------
static const PRUnichar kSpaceCh = PRUnichar(' ');
static const nsGlyphCode kNullGlyph = {{0, 0}, 0};
typedef enum {eExtension_base, eExtension_variants, eExtension_parts}
nsMathfontPrefExtension;
// -----------------------------------------------------------------------------------
// nsGlyphTable is a class that provides an interface for accessing glyphs
// of stretchy chars. It acts like a table that stores the variants of bigger
// sizes (if any) and the partial glyphs needed to build extensible symbols.
// An instance of nsGlyphTable is associated to one primary font. Extra glyphs
// can be taken in other additional fonts when stretching certain characters.
// These supplementary fonts are referred to as "external" fonts to the table.
//
// A char for which nsGlyphTable::Has(aChar) is true means that the table
// contains some glyphs (bigger and/or partial) that can be used to render
// the char. Bigger sizes (if any) of the char can then be retrieved with
// BigOf(aSize). Partial glyphs can be retrieved with TopOf(), GlueOf(), etc.
//
// A table consists of "nsGlyphCode"s which are viewed either as Unicode
// points or as direct glyph indices, depending on the type of the table.
// XXX The latter is not yet supported.
// General format of MathFont Property Files from which glyph data are retrieved:
// -----------------------------------------------------------------------------------
// Each font should have its set of glyph data. For example, the glyph data for
// the "Symbol" font and the "MT Extra" font are in "mathfontSymbol.properties"
// and "mathfontMTExtra.properties", respectively. The mathfont property file is a
// set of all the stretchy MathML characters that can be rendered with that font
// using larger and/or partial glyphs. The entry of each stretchy character in the
// mathfont property file gives, in that order, the 4 partial glyphs: Top (or Left),
// Middle, Bottom (or Right), Glue; and the variants of bigger sizes (if any).
// A position that is not relevant to a particular character is indicated there
// with the UNICODE REPLACEMENT CHARACTER 0xFFFD.
// Characters that need to be built recursively from other characters are said
// to be composite. For example, chars like over/underbrace in CMEX10 have to
// be built from two half stretchy chars and joined in the middle (TeXbook, p.225).
// Such chars are handled in a special manner by the nsMathMLChar class, which allows
// several (2 or more) child chars to be composed in order to render another char.
// To specify such chars, their list of glyphs in the property file should be given
// as space-separated segments of glyphs. Each segment gives the 4 partial
// glyphs with which to build the child char that will be joined with its other
// siblings. In this code, when this situation happens (see the detailed description
// of Stretch() below), the original char (referred to as "parent") creates a
// singly-linked list of child chars, asking them to stretch in an equally divided
// space. The nsGlyphTable embeds the necessary logic to guarantee correctness in a
// recursive stretch (and in the use of TopOf(), GlueOf(), etc) on these child chars.
// -----------------------------------------------------------------------------------
#define NS_TABLE_TYPE_UNICODE 0
#define NS_TABLE_TYPE_GLYPH_INDEX 1
#define NS_TABLE_STATE_ERROR -1
#define NS_TABLE_STATE_EMPTY 0
#define NS_TABLE_STATE_READY 1
// helper to trim off comments from data in a MathFont Property File
static void
Clean(nsString& aValue)
{
// chop the trailing # comment portion if any ...
PRInt32 comment = aValue.RFindChar('#');
if (comment > 0) aValue.Truncate(comment);
aValue.CompressWhitespace();
}
// helper to load a MathFont Property File
static nsresult
LoadProperties(const nsString& aName,
nsCOMPtr<nsIPersistentProperties>& aProperties)
{
nsAutoString uriStr;
uriStr.AssignLiteral("resource://gre/res/fonts/mathfont");
uriStr.Append(aName);
uriStr.StripWhitespace(); // that may come from aName
uriStr.AppendLiteral(".properties");
return NS_LoadPersistentPropertiesFromURISpec(getter_AddRefs(aProperties),
NS_ConvertUTF16toUTF8(uriStr));
}
// -----------------------------------------------------------------------------------
class nsGlyphTable {
public:
explicit nsGlyphTable(const nsString& aPrimaryFontName)
: mType(NS_TABLE_TYPE_UNICODE),
mFontName(1), // ensure space for primary font name.
mState(NS_TABLE_STATE_EMPTY),
mCharCache(0)
{
MOZ_COUNT_CTOR(nsGlyphTable);
mFontName.AppendElement(aPrimaryFontName);
}
~nsGlyphTable() // not a virtual destructor: this class is not intended to be subclassed
{
MOZ_COUNT_DTOR(nsGlyphTable);
}
const nsAString& PrimaryFontName() const
{
return mFontName[0];
}
const nsAString& FontNameFor(const nsGlyphCode& aGlyphCode) const
{
return mFontName[aGlyphCode.font];
}
// True if this table contains some glyphs (variants and/or parts)
// or contains child chars that can be used to render this char
PRBool Has(nsPresContext* aPresContext, nsMathMLChar* aChar);
// True if this table contains variants of larger sizes to render this char
PRBool HasVariantsOf(nsPresContext* aPresContext, nsMathMLChar* aChar);
// True if this table contains parts (or composite parts) to render this char
PRBool HasPartsOf(nsPresContext* aPresContext, nsMathMLChar* aChar);
// True if aChar is to be assembled from other child chars in this table
PRBool IsComposite(nsPresContext* aPresContext, nsMathMLChar* aChar);
// The number of child chars to assemble in order to render aChar
PRInt32 ChildCountOf(nsPresContext* aPresContext, nsMathMLChar* aChar);
// Getters for the parts
nsGlyphCode TopOf(nsPresContext* aPresContext, nsMathMLChar* aChar) {
return ElementAt(aPresContext, aChar, 0);
}
nsGlyphCode MiddleOf(nsPresContext* aPresContext, nsMathMLChar* aChar) {
return ElementAt(aPresContext, aChar, 1);
}
nsGlyphCode BottomOf(nsPresContext* aPresContext, nsMathMLChar* aChar) {
return ElementAt(aPresContext, aChar, 2);
}
nsGlyphCode GlueOf(nsPresContext* aPresContext, nsMathMLChar* aChar) {
return ElementAt(aPresContext, aChar, 3);
}
nsGlyphCode BigOf(nsPresContext* aPresContext, nsMathMLChar* aChar, PRInt32 aSize) {
return ElementAt(aPresContext, aChar, 4 + aSize);
}
nsGlyphCode LeftOf(nsPresContext* aPresContext, nsMathMLChar* aChar) {
return ElementAt(aPresContext, aChar, 0);
}
nsGlyphCode RightOf(nsPresContext* aPresContext, nsMathMLChar* aChar) {
return ElementAt(aPresContext, aChar, 2);
}
private:
nsGlyphCode ElementAt(nsPresContext* aPresContext, nsMathMLChar* aChar, PRUint32 aPosition);
// The type is either NS_TABLE_TYPE_UNICODE or NS_TABLE_TYPE_GLYPH_INDEX
PRInt32 mType;
// mFontName[0] is the primary font associated to this table. The others
// are possible "external" fonts for glyphs not in the primary font
// but which are needed to stretch certain characters in the table
nsTArray<nsString> mFontName;
// Tri-state variable for error/empty/ready
PRInt32 mState;
// The set of glyph data in this table, as provided by the MathFont Property File
nsCOMPtr<nsIPersistentProperties> mGlyphProperties;
// For speedy re-use, we always cache the last data used in the table.
// mCharCache is the Unicode point of the last char that was queried in this
// table. mGlyphCache is a buffer containing the glyph data associated to
// that char. For a property line 'key = value' in the MathFont Property File,
// mCharCache will retain the 'key' -- which is a Unicode point, while mGlyphCache
// will retain the 'value', which is a consecutive list of nsGlyphCodes, i.e.,
// the pairs of 'code@font' needed by the char -- in which 'code@0' can be specified
// without the optional '@0'. However, to ease subsequent processing, mGlyphCache
// excludes the '@' symbol and explicitly inserts all optional '0' that indicates
// the primary font identifier. Specifically therefore, the k-th glyph is
// characterized by :
// 1) mGlyphCache[3*k],mGlyphCache[3*k+1] : its Unicode point (or glyph index -- depending on mType),
// 2) mGlyphCache[3*k+2] : the numeric identifier of the font where it comes from.
// A font identifier of '0' means the default primary font associated to this
// table. Other digits map to the "external" fonts that may have been specified
// in the MathFont Property File.
nsString mGlyphCache;
PRUnichar mCharCache;
};
nsGlyphCode
nsGlyphTable::ElementAt(nsPresContext* aPresContext, nsMathMLChar* aChar, PRUint32 aPosition)
{
if (mState == NS_TABLE_STATE_ERROR) return kNullGlyph;
// Load glyph properties if this is the first time we have been here
if (mState == NS_TABLE_STATE_EMPTY) {
nsresult rv = LoadProperties(mFontName[0], mGlyphProperties);
#ifdef NS_DEBUG
nsCAutoString uriStr;
uriStr.AssignLiteral("resource://gre/res/fonts/mathfont");
LossyAppendUTF16toASCII(mFontName[0], uriStr);
uriStr.StripWhitespace(); // that may come from mFontName
uriStr.AppendLiteral(".properties");
printf("Loading %s ... %s\n",
uriStr.get(),
(NS_FAILED(rv)) ? "Failed" : "Done");
#endif
if (NS_FAILED(rv)) {
mState = NS_TABLE_STATE_ERROR; // never waste time with this table again
return kNullGlyph;
}
mState = NS_TABLE_STATE_READY;
// see if there are external fonts needed for certain chars in this table
nsCAutoString key;
nsAutoString value;
for (PRInt32 i = 1; ; i++) {
key.AssignLiteral("external.");
key.AppendInt(i, 10);
rv = mGlyphProperties->GetStringProperty(key, value);
if (NS_FAILED(rv)) break;
Clean(value);
mFontName.AppendElement(value); // i.e., mFontName[i] holds this font name
}
}
// If aChar is a child char to be used by a parent composite char, make
// sure that it is really attached to this table
if (aChar->mParent && (aChar->mGlyphTable != this)) return kNullGlyph;
// Update our cache if it is not associated to this character
PRUnichar uchar = aChar->mData[0];
if (mCharCache != uchar) {
// The key in the property file is interpreted as ASCII and kept
// as such ...
char key[10]; PR_snprintf(key, sizeof(key), "\\u%04X", uchar);
nsAutoString value;
nsresult rv = mGlyphProperties->GetStringProperty(nsDependentCString(key), value);
if (NS_FAILED(rv)) return kNullGlyph;
Clean(value);
// See if this char uses external fonts; e.g., if the 2nd glyph is taken from the
// external font '1', the property line looks like \uNNNN = \uNNNN\uNNNN@1\uNNNN.
// This is where mGlyphCache is pre-processed to explicitly store all glyph codes
// as combined pairs of 'code@font', excluding the '@' separator. This means that
// mGlyphCache[3*k],mGlyphCache[3*k+1] will later be rendered with mFontName[mGlyphCache[3*k+2]]
// Note: font identifier is internally an ASCII digit to avoid the null char issue
nsAutoString buffer;
PRInt32 length = value.Length();
PRInt32 i = 0; // index in value
PRInt32 j = 0; // part/variant index
while (i < length) {
PRUnichar code = value[i];
++i;
buffer.Append(code);
// see if we are at the beginning of a child char
if (code == kSpaceCh) {
// reset the annotation indicator to be 0 for the next code point
j = -1;
}
#if 0 // If we want this then the nsGlyphTableList must be declared
// or the UnicodeTable could be made a global.
// See if this code point is an *indirect reference* to the Unicode
// table and lookup the code there.
else if (code == PRUnichar(0xF8FF) && gGlyphTableList &&
this != &gGlyphTableList->mUnicodeTable) {
code = gGlyphTableList->mUnicodeTable.
ElementAt(aPresContext, aChar, aPosition).code;
}
// see if this code point is a *direct reference* to
// the Unicode table, and lookup the [TLMBRG1-9] position for code.
else if ((i+1 < length) && (value[i] == PRUnichar('.'))) {
++i;
// Need to implement this if we want it:
// Set (new) code from the value[i] position for (current) code.
if (1)
return kNullGlyph;
++i;
}
#endif
// Read the next word if we have a non-BMP character.
if (i < length && NS_IS_HIGH_SURROGATE(code)) {
code = value[i];
++i;
} else {
code = PRUnichar('\0');
}
buffer.Append(code);
// See if an external font is needed for the code point.
// Limit of 9 external fonts
PRUnichar font = 0;
if (i+1 < length && value[i] == PRUnichar('@') &&
value[i+1] >= PRUnichar('0') && value[i+1] <= PRUnichar('9')) {
++i;
font = value[i] - '0';
++i;
if (font >= mFontName.Length()) {
NS_ERROR("Nonexistent font referenced in glyph table");
return kNullGlyph;
}
// The char cannot be handled if this font is not installed
if (!mFontName[font].Length()) {
return kNullGlyph;
}
}
buffer.Append(font);
++j;
}
// update our cache with the new settings
mGlyphCache.Assign(buffer);
mCharCache = uchar;
}
// If aChar is a composite char, only its children are allowed
// to use its glyphs in this table, i.e., the parent char itself
// is disabled and cannot be stretched directly with these glyphs.
// This guarantees a coherent behavior in Stretch().
if (!aChar->mParent && (kNotFound != mGlyphCache.FindChar(kSpaceCh))) {
return kNullGlyph;
}
// If aChar is a child char, the index of the glyph is relative to
// the offset of the list of glyphs corresponding to the child char.
PRUint32 offset = 0;
PRUint32 length = mGlyphCache.Length();
if (aChar->mParent) {
nsMathMLChar* child = aChar->mParent->mSibling;
// XXXkt composite chars can't have size variants
while (child && (child != aChar)) {
offset += 5; // skip the 4 partial glyphs + the whitespace separator
child = child->mSibling;
}
length = 3*(offset + 4); // stay confined in the 4 partial glyphs of this child
}
PRUint32 index = 3*(offset + aPosition); // 3* is to account for the code@font pairs
if (index+2 >= length) return kNullGlyph;
nsGlyphCode ch;
ch.code[0] = mGlyphCache.CharAt(index);
ch.code[1] = mGlyphCache.CharAt(index + 1);
ch.font = mGlyphCache.CharAt(index + 2);
return ch.code[0] == PRUnichar(0xFFFD) ? kNullGlyph : ch;
}
PRBool
nsGlyphTable::IsComposite(nsPresContext* aPresContext, nsMathMLChar* aChar)
{
// there is only one level of recursion in our model. a child
// cannot be composite because it cannot have its own children
if (aChar->mParent) return PR_FALSE;
// shortcut to sync the cache with this char...
mCharCache = 0; mGlyphCache.Truncate(); ElementAt(aPresContext, aChar, 0);
// the cache remained empty if the char wasn't found in this table
if (4*3 >= mGlyphCache.Length()) return PR_FALSE;
// the lists of glyphs of a composite char are space-separated
return (kSpaceCh == mGlyphCache.CharAt(4*3));
}
PRInt32
nsGlyphTable::ChildCountOf(nsPresContext* aPresContext, nsMathMLChar* aChar)
{
// this will sync the cache as well ...
if (!IsComposite(aPresContext, aChar)) return 0;
// the lists of glyphs of a composite char are space-separated
return 1 + mGlyphCache.CountChar(kSpaceCh);
}
PRBool
nsGlyphTable::Has(nsPresContext* aPresContext, nsMathMLChar* aChar)
{
return HasVariantsOf(aPresContext, aChar) || HasPartsOf(aPresContext, aChar);
}
PRBool
nsGlyphTable::HasVariantsOf(nsPresContext* aPresContext, nsMathMLChar* aChar)
{
//XXXkt all variants must be in the same file as size 1
return BigOf(aPresContext, aChar, 1).Exists();
}
PRBool
nsGlyphTable::HasPartsOf(nsPresContext* aPresContext, nsMathMLChar* aChar)
{
return GlueOf(aPresContext, aChar).Exists() ||
TopOf(aPresContext, aChar).Exists() ||
BottomOf(aPresContext, aChar).Exists() ||
MiddleOf(aPresContext, aChar).Exists() ||
IsComposite(aPresContext, aChar);
}
// -----------------------------------------------------------------------------------
// This is the list of all the applicable glyph tables.
// We will maintain a single global instance that will only reveal those
// glyph tables that are associated to fonts currently installed on the
// user' system. The class is an XPCOM shutdown observer to allow us to
// free its allocated data at shutdown
class nsGlyphTableList : public nsIObserver
{
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIOBSERVER
nsGlyphTable mUnicodeTable;
nsGlyphTableList()
: mUnicodeTable(NS_LITERAL_STRING("Unicode"))
{
MOZ_COUNT_CTOR(nsGlyphTableList);
}
virtual ~nsGlyphTableList()
{
MOZ_COUNT_DTOR(nsGlyphTableList);
}
nsresult Initialize();
nsresult Finalize();
// Add a glyph table in the list, return the new table that was added
nsGlyphTable*
AddGlyphTable(const nsString& aPrimaryFontName);
// Find a glyph table in the list that has a glyph for the given char
nsGlyphTable*
GetGlyphTableFor(nsPresContext* aPresContext,
nsMathMLChar* aChar);
// Find the glyph table in the list corresponding to the given font family.
nsGlyphTable*
GetGlyphTableFor(const nsAString& aFamily);
private:
nsGlyphTable* TableAt(PRInt32 aIndex) {
return &mTableList.ElementAt(aIndex);
}
PRInt32 Count() {
return mTableList.Length();
}
// List of glyph tables;
nsTArray<nsGlyphTable> mTableList;
};
NS_IMPL_ISUPPORTS1(nsGlyphTableList, nsIObserver)
// -----------------------------------------------------------------------------------
// Here is the global list of applicable glyph tables that we will be using
static nsGlyphTableList* gGlyphTableList = nsnull;
static PRBool gInitialized = PR_FALSE;
// XPCOM shutdown observer
NS_IMETHODIMP
nsGlyphTableList::Observe(nsISupports* aSubject,
const char* aTopic,
const PRUnichar* someData)
{
Finalize();
return NS_OK;
}
// Add an observer to XPCOM shutdown so that we can free our data at shutdown
nsresult
nsGlyphTableList::Initialize()
{
nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
if (!obs)
return NS_ERROR_FAILURE;
nsresult rv = obs->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, PR_FALSE);
NS_ENSURE_SUCCESS(rv, rv);
return NS_OK;
}
// Remove our observer and free the memory that were allocated for us
nsresult
nsGlyphTableList::Finalize()
{
// Remove our observer from the observer service
nsresult rv = NS_OK;
nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
if (obs)
rv = obs->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
else
rv = NS_ERROR_FAILURE;
gInitialized = PR_FALSE;
// our oneself will be destroyed when our |Release| is called by the observer
return rv;
}
nsGlyphTable*
nsGlyphTableList::AddGlyphTable(const nsString& aPrimaryFontName)
{
// See if there is already a special table for this family.
nsGlyphTable* glyphTable = GetGlyphTableFor(aPrimaryFontName);
if (glyphTable != &mUnicodeTable)
return glyphTable;
// allocate a table
glyphTable = mTableList.AppendElement(aPrimaryFontName);
return glyphTable;
}
nsGlyphTable*
nsGlyphTableList::GetGlyphTableFor(nsPresContext* aPresContext,
nsMathMLChar* aChar)
{
if (mUnicodeTable.Has(aPresContext, aChar))
return &mUnicodeTable;
PRInt32 i;
for (i = 0; i < Count(); i++) {
nsGlyphTable* glyphTable = TableAt(i);
if (glyphTable->Has(aPresContext, aChar)) {
return glyphTable;
}
}
return nsnull;
}
nsGlyphTable*
nsGlyphTableList::GetGlyphTableFor(const nsAString& aFamily)
{
for (PRInt32 i = 0; i < Count(); i++) {
nsGlyphTable* glyphTable = TableAt(i);
const nsAString& fontName = glyphTable->PrimaryFontName();
// TODO: would be nice to consider StripWhitespace and other aliasing
if (fontName.Equals(aFamily, nsCaseInsensitiveStringComparator())) {
return glyphTable;
}
}
// Fall back to default Unicode table
return &mUnicodeTable;
}
// -----------------------------------------------------------------------------------
// Lookup the preferences:
// "font.mathfont-family.\uNNNN.base" -- fonts for the base size
// "font.mathfont-family.\uNNNN.variants" -- fonts for larger glyphs
// "font.mathfont-family.\uNNNN.parts" -- fonts for partial glyphs
// Given the char code and mode of stretch, retrieve the preferred extension
// font families.
static PRBool
GetFontExtensionPref(PRUnichar aChar,
nsMathfontPrefExtension aExtension, nsString& aValue)
{
// initialize OUT param
aValue.Truncate();
// We are going to try two keys because some users specify their pref as
// user_pref("font.mathfont-family.\uNNNN.base", "...") rather than
// user_pref("font.mathfont-family.\\uNNNN.base", "...").
// The \uNNNN in the former is interpreted as an UTF16 escape sequence by
// JavaScript and is converted to the internal UTF8 string that JavaScript uses.
// But clueless users who are not savvy of JavaScript have no idea as to what
// is going on and are baffled as to why their pref setting is not working.
// So to save countless explanations, we are going to support both keys.
static const char* kMathFontPrefix = "font.mathfont-family.";
nsCAutoString extension;
switch (aExtension)
{
case eExtension_base:
extension.AssignLiteral(".base");
break;
case eExtension_variants:
extension.AssignLiteral(".variants");
break;
case eExtension_parts:
extension.AssignLiteral(".parts");
break;
default:
return PR_FALSE;
}
// .\\uNNNN key
nsCAutoString key;
key.AssignASCII(kMathFontPrefix);
char ustr[10];
PR_snprintf(ustr, sizeof(ustr), "\\u%04X", aChar);
key.Append(ustr);
key.Append(extension);
// .\uNNNN key
nsCAutoString alternateKey;
alternateKey.AssignASCII(kMathFontPrefix);
NS_ConvertUTF16toUTF8 tmp(&aChar, 1);
alternateKey.Append(tmp);
alternateKey.Append(extension);
aValue = Preferences::GetString(key.get());
if (aValue.IsEmpty()) {
aValue = Preferences::GetString(alternateKey.get());
}
return !aValue.IsEmpty();
}
static PRBool
MathFontEnumCallback(const nsString& aFamily, PRBool aGeneric, void *aData)
{
if (!gGlyphTableList->AddGlyphTable(aFamily))
return PR_FALSE; // stop in low-memory situations
return PR_TRUE; // don't stop
}
static nsresult
InitGlobals(nsPresContext* aPresContext)
{
NS_ASSERTION(!gInitialized, "Error -- already initialized");
gInitialized = PR_TRUE;
// Allocate the placeholders for the preferred parts and variants
nsresult rv = NS_ERROR_OUT_OF_MEMORY;
gGlyphTableList = new nsGlyphTableList();
if (gGlyphTableList) {
rv = gGlyphTableList->Initialize();
}
if (NS_FAILED(rv)) {
delete gGlyphTableList;
gGlyphTableList = nsnull;
return rv;
}
/*
else
The gGlyphTableList has been successfully registered as a shutdown observer.
It will be deleted at shutdown, even if a failure happens below.
*/
nsCAutoString key;
nsAutoString value;
nsCOMPtr<nsIPersistentProperties> mathfontProp;
// Add the math fonts in the gGlyphTableList in order of preference ...
// Note: we only load font-names at this stage. The actual glyph tables will
// be loaded lazily (see nsGlyphTable::ElementAt()).
// Load the "mathfont.properties" file
value.Truncate();
rv = LoadProperties(value, mathfontProp);
if (NS_FAILED(rv)) return rv;
// Get the list of mathfonts having special glyph tables to be used for
// stretchy characters.
// We just want to iterate over the font-family list using the
// callback mechanism that nsFont has...
nsFont font("", 0, 0, 0, 0, 0, 0);
NS_NAMED_LITERAL_CSTRING(defaultKey, "font.mathfont-glyph-tables");
rv = mathfontProp->GetStringProperty(defaultKey, font.name);
if (NS_FAILED(rv)) return rv;
// Parse the font list and append an entry for each family to gGlyphTableList
nsAutoString missingFamilyList;
font.EnumerateFamilies(MathFontEnumCallback, nsnull);
return rv;
}
// -----------------------------------------------------------------------------------
// And now the implementation of nsMathMLChar
nsStyleContext*
nsMathMLChar::GetStyleContext() const
{
NS_ASSERTION(!mParent, "invalid call - not allowed for child chars");
NS_ASSERTION(mStyleContext, "chars should always have style context");
return mStyleContext;
return NS_OK;
}
void
nsMathMLChar::SetStyleContext(nsStyleContext* aStyleContext)
{
NS_ASSERTION(!mParent, "invalid call - not allowed for child chars");
NS_PRECONDITION(aStyleContext, "null ptr");
if (aStyleContext != mStyleContext) {
if (mStyleContext)
mStyleContext->Release();
if (aStyleContext) {
mStyleContext = aStyleContext;
aStyleContext->AddRef();
// Sync the pointers of child chars.
nsMathMLChar* child = mSibling;
while (child) {
child->mStyleContext = mStyleContext;
child = child->mSibling;
}
}
}
}
void
nsMathMLChar::SetData(nsPresContext* aPresContext,
nsString& aData)
{
NS_ASSERTION(!mParent, "invalid call - not allowed for child chars");
if (!gInitialized) {
InitGlobals(aPresContext);
}
mData = aData;
// some assumptions until proven otherwise
// note that mGlyph is not initialized
mDirection = NS_STRETCH_DIRECTION_UNSUPPORTED;
mBoundingMetrics = nsBoundingMetrics();
mGlyphTable = nsnull;
// check if stretching is applicable ...
if (gGlyphTableList && (1 == mData.Length())) {
mDirection = nsMathMLOperators::GetStretchyDirection(mData);
// default tentative table (not the one that is necessarily going
// to be used)
mGlyphTable = gGlyphTableList->GetGlyphTableFor(aPresContext, this);
}
}
// -----------------------------------------------------------------------------------
/*
The Stretch:
@param aContainerSize - suggested size for the stretched char
@param aDesiredStretchSize - OUT parameter. The desired size
after stretching. If no stretching is done, the output will
simply give the base size.
How it works?
Summary:-
The Stretch() method first looks for a glyph of appropriate
size; If a glyph is found, it is cached by this object and
its size is returned in aDesiredStretchSize. The cached
glyph will then be used at the painting stage.
If no glyph of appropriate size is found, a search is made
to see if the char can be built by parts.
Details:-
A character gets stretched through the following pipeline :
1) If the base size of the char is sufficient to cover the
container' size, we use that. If not, it will still be
used as a fallback if the other stages in the pipeline fail.
Issues :
a) The base size, the parts and the variants of a char can
be in different fonts. For eg., the base size for '(' should
come from a normal ascii font if CMEX10 is used, since CMEX10
only contains the stretched versions. Hence, there are two
style contexts in use throughout the process. The leaf style
context of the char holds fonts with which to try to stretch
the char. The parent style context of the char contains fonts
for normal rendering. So the parent context is the one used
to get the initial base size at the start of the pipeline.
b) For operators that can be largeop's in display mode,
we will skip the base size even if it fits, so that
the next stage in the pipeline is given a chance to find
a largeop variant. If the next stage fails, we fallback
to the base size.
2) We search for the first larger variant of the char that fits the
container' size. We first search for larger variants using the glyph
table corresponding to the first existing font specified in the list of
stretchy fonts held by the leaf style context (from -moz-math-stretchy in
mathml.css). Generic fonts are resolved by the preference
"font.mathfont-family".
Issues :
a) the largeop and display settings determine the starting
size when we do the above search, regardless of whether
smaller variants already fit the container' size.
b) if it is a largeopOnly request (i.e., a displaystyle operator
with largeop=true and stretchy=false), we break after finding
the first starting variant, regardless of whether that
variant fits the container's size.
3) If a variant of appropriate size wasn't found, we see if the char
can be built by parts using the same glyph table.
Issues:
a) Certain chars like over/underbrace in CMEX10 have to be built
from two half stretchy chars and joined in the middle. Such
chars are handled in a special manner. When this situation is
detected, the initial char (referred to as "parent") creates a
singly-linked list of child chars, asking them to stretch in
a divided space. A convention is used in the setup of
nsGlyphTable to express that a composite parent char can be built
from child chars.
b) There are some chars that have no middle and glue glyphs. For
such chars, the parts need to be joined using the rule.
By convention (TeXbook p.225), the descent of the parts is
zero while their ascent gives the thickness of the rule that
should be used to join them.
4) If a match was not found in that glyph table, repeat from 2 to search the
ordered list of stretchy fonts for the first font with a glyph table that
provides a fit to the container size. If no fit is found, the closest fit
is used.
Of note:
When the pipeline completes successfully, the desired size of the
stretched char can actually be slightly larger or smaller than
aContainerSize. But it is the responsibility of the caller to
account for the spacing when setting aContainerSize, and to leave
any extra margin when placing the stretched char.
*/
// -----------------------------------------------------------------------------------
// plain TeX settings (TeXbook p.152)
#define NS_MATHML_DELIMITER_FACTOR 0.901f
#define NS_MATHML_DELIMITER_SHORTFALL_POINTS 5.0f
static PRBool
IsSizeOK(nsPresContext* aPresContext, nscoord a, nscoord b, PRUint32 aHint)
{
// Normal: True if 'a' is around +/-10% of the target 'b' (10% is
// 1-DelimiterFactor). This often gives a chance to the base size to
// win, especially in the context of <mfenced> without tall elements
// or in sloppy markups without protective <mrow></mrow>
PRBool isNormal =
(aHint & NS_STRETCH_NORMAL)
&& PRBool(float(NS_ABS(a - b))
< (1.0f - NS_MATHML_DELIMITER_FACTOR) * float(b));
// Nearer: True if 'a' is around max{ +/-10% of 'b' , 'b' - 5pt },
// as documented in The TeXbook, Ch.17, p.152.
// i.e. within 10% and within 5pt
PRBool isNearer = PR_FALSE;
if (aHint & (NS_STRETCH_NEARER | NS_STRETCH_LARGEOP)) {
float c = NS_MAX(float(b) * NS_MATHML_DELIMITER_FACTOR,
float(b) - nsPresContext::CSSPointsToAppUnits(NS_MATHML_DELIMITER_SHORTFALL_POINTS));
isNearer = PRBool(float(NS_ABS(b - a)) <= (float(b) - c));
}
// Smaller: Mainly for transitory use, to compare two candidate
// choices
PRBool isSmaller =
(aHint & NS_STRETCH_SMALLER)
&& PRBool((float(a) >= (NS_MATHML_DELIMITER_FACTOR * float(b)))
&& (a <= b));
// Larger: Critical to the sqrt code to ensure that the radical
// size is tall enough
PRBool isLarger =
(aHint & (NS_STRETCH_LARGER | NS_STRETCH_LARGEOP))
&& PRBool(a >= b);
return (isNormal || isSmaller || isNearer || isLarger);
}
static PRBool
IsSizeBetter(nscoord a, nscoord olda, nscoord b, PRUint32 aHint)
{
if (0 == olda)
return PR_TRUE;
if (aHint & (NS_STRETCH_LARGER | NS_STRETCH_LARGEOP))
return (a >= olda) ? (olda < b) : (a >= b);
if (aHint & NS_STRETCH_SMALLER)
return (a <= olda) ? (olda > b) : (a <= b);
// XXXkt prob want log scale here i.e. 1.5 is closer to 1 than 0.5
return NS_ABS(a - b) < NS_ABS(olda - b);
}
// We want to place the glyphs even when they don't fit at their
// full extent, i.e., we may clip to tolerate a small amount of
// overlap between the parts. This is important to cater for fonts
// with long glues.
static nscoord
ComputeSizeFromParts(nsPresContext* aPresContext,
nsGlyphCode* aGlyphs,
nscoord* aSizes,
nscoord aTargetSize)
{
enum {first, middle, last, glue};
// Add the parts that cannot be left out.
nscoord sum = 0;
for (PRInt32 i = first; i <= last; i++) {
if (aGlyphs[i] != aGlyphs[glue]) {
sum += aSizes[i];
}
}
// Determine how much is used in joins
nscoord oneDevPixel = aPresContext->AppUnitsPerDevPixel();
PRInt32 joins = aGlyphs[middle] == aGlyphs[glue] ? 1 : 2;
// Pick a maximum size using a maximum number of glue glyphs that we are
// prepared to draw for one character.
const PRInt32 maxGlyphs = 1000;
// This also takes into account the fact that, if the glue has no size,
// then the character can't be lengthened.
nscoord maxSize = sum - 2 * joins * oneDevPixel + maxGlyphs * aSizes[glue];
if (maxSize < aTargetSize)
return maxSize; // settle with the maximum size
// Get the minimum allowable size using some flex.
nscoord minSize = NSToCoordRound(NS_MATHML_DELIMITER_FACTOR * sum);
if (minSize > aTargetSize)
return minSize; // settle with the minimum size
// Fill-up the target area
return aTargetSize;
}
// Insert aFallbackFamilies before the first generic family in or at the end
// of a CSS aFontName.
static void
AddFallbackFonts(nsAString& aFontName, const nsAString& aFallbackFamilies)
{
if (aFallbackFamilies.IsEmpty())
return;
if (aFontName.IsEmpty()) {
return;
}
static const PRUnichar kSingleQuote = PRUnichar('\'');
static const PRUnichar kDoubleQuote = PRUnichar('\"');
static const PRUnichar kComma = PRUnichar(',');
const PRUnichar *p_begin, *p_end;
aFontName.BeginReading(p_begin);
aFontName.EndReading(p_end);
const PRUnichar *p = p_begin;
const PRUnichar *p_name = nsnull;
while (p < p_end) {
while (nsCRT::IsAsciiSpace(*p))
if (++p == p_end)
goto insert;
p_name = p;
if (*p == kSingleQuote || *p == kDoubleQuote) {
// quoted font family
PRUnichar quoteMark = *p;
if (++p == p_end)