path: root/src/kernel/qfont_x11.cpp

/****************************************************************************
**
** Implementation of QFont, QFontMetrics and QFontInfo classes for X11
**
** Created : 940515
**
** Copyright (C) 1992-2008 Trolltech ASA.  All rights reserved.
**
** This file is part of the kernel module of the Qt GUI Toolkit.
**
** This file may be used under the terms of the GNU General
** Public License versions 2.0 or 3.0 as published by the Free
** Software Foundation and appearing in the files LICENSE.GPL2
** and LICENSE.GPL3 included in the packaging of this file.
** Alternatively you may (at your option) use any later version
** of the GNU General Public License if such license has been
** publicly approved by Trolltech ASA (or its successors, if any)
** and the KDE Free Qt Foundation.
**
** Please review the following information to ensure GNU General
** Public Licensing requirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/.
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at sales@trolltech.com.
**
** This file may be used under the terms of the Q Public License as
** defined by Trolltech ASA and appearing in the file LICENSE.QPL
** included in the packaging of this file.  Licensees holding valid Qt
** Commercial licenses may use this file in accordance with the Qt
** Commercial License Agreement provided with the Software.
**
** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted
** herein.
**
**********************************************************************/

#define QT_FATAL_ASSERT

// REVISED: brad

#include "qplatformdefs.h"

#include "qfont.h"
#include "qapplication.h"
#include "qcleanuphandler.h"
#include "qfontinfo.h"
#include "qfontdatabase.h"
#include "qfontmetrics.h"
#include "qpaintdevice.h"
#include "qpaintdevicemetrics.h"
#include "qtextcodec.h"

#include <private/qfontcodecs_p.h>
#include <private/qunicodetables_p.h>
#include "qfontdata_p.h"
#include "qfontengine_p.h"
#include "qtextengine_p.h"

#include "qt_x11_p.h"

#include <time.h>
#include <stdlib.h>
#include <ctype.h>

#define QFONTLOADER_DEBUG
#define QFONTLOADER_DEBUG_VERBOSE

Q_EXPORT bool qt_has_xft = FALSE;

#ifndef QT_NO_XFTFREETYPE
Qt::HANDLE qt_xft_handle(const QFont &font)
{
    QFontEngine *engine = font.d->engineForScript( QFontPrivate::defaultScript );
    if (!engine->type() == QFontEngine::Xft)
        return 0;
    return (long)static_cast<QFontEngineXft *>(engine)->font();
}
#endif

double qt_pixelSize(double pointSize, QPaintDevice *paintdevice, int scr)
{
    if (pointSize < 0) return -1.;

    double result = pointSize;
    if (paintdevice && QPaintDeviceMetrics( paintdevice ).logicalDpiY() != 75)
	result *= QPaintDeviceMetrics( paintdevice ).logicalDpiY() / 72.;
    else if (QPaintDevice::x11AppDpiY( scr ) != 75)
	result *= QPaintDevice::x11AppDpiY( scr ) / 72.;

    return result;
}

double qt_pointSize(double pixelSize, QPaintDevice *paintdevice, int scr)
{
    if (pixelSize < 0) return -1.;

    double result = pixelSize;
    if ( paintdevice && QPaintDeviceMetrics( paintdevice ).logicalDpiY() != 75)
	result *= 72. / QPaintDeviceMetrics( paintdevice ).logicalDpiY();
    else if (QPaintDevice::x11AppDpiY(scr) != 75)
	result *= 72. / QPaintDevice::x11AppDpiY( scr );

    return result;
}

static inline double pixelSize( const QFontDef &request, QPaintDevice *paintdevice,
				int scr )
{
    return ((request.pointSize != -1) ?
	    qt_pixelSize(request.pointSize / 10., paintdevice, scr) :
	    (double)request.pixelSize);
}

static inline double pointSize( const QFontDef &request, QPaintDevice *paintdevice,
				int scr )
{
    return ((request.pixelSize != -1) ?
	    qt_pointSize(request.pixelSize, paintdevice, scr) * 10.:
	    (double)request.pointSize);
}


/*
  Removes wildcards from an XLFD.

  Returns \a xlfd with all wildcards removed if a match for \a xlfd is
  found, otherwise it returns \a xlfd.
*/
static QCString qt_fixXLFD( const QCString &xlfd )
{
    QCString ret = xlfd;
    int count = 0;
    char **fontNames =
	XListFonts( QPaintDevice::x11AppDisplay(), xlfd, 32768, &count );
    if ( count > 0 )
	ret = fontNames[0];
    XFreeFontNames( fontNames );
    return ret ;
}

typedef QMap<QFont::Script,QString> FallbackMap;
static FallbackMap *fallbackMap = 0;
static QSingleCleanupHandler<FallbackMap> qt_fallback_font_family_cleanup;

static void ensure_fallback_map()
{
    if ( fallbackMap ) return;
    fallbackMap = new FallbackMap;
    qt_fallback_font_family_cleanup.set( &fallbackMap );
}

// Returns the user-configured fallback family for the specified script.
QString qt_fallback_font_family( QFont::Script script )
{
    QString ret;

    if ( fallbackMap ) {
	FallbackMap::ConstIterator it, end = fallbackMap->end();
	it = fallbackMap->find( script );
	if ( it != end )
	    ret = it.data();
    }

    return ret;
}

// Sets the fallback family for the specified script.
void qt_set_fallback_font_family( QFont::Script script, const QString &family )
{
    ensure_fallback_map();

    if ( ! family.isEmpty() )
	fallbackMap->insert( script, family );
    else
	fallbackMap->remove( script );
}


QFont::Script QFontPrivate::defaultScript = QFont::UnknownScript;
int QFontPrivate::defaultEncodingID = -1;

/*!
  Internal function that initializes the font system.

  \internal
  The font cache and font dict do not alloc the keys. The key is a QString
  which is shared between QFontPrivate and QXFontName.
*/
void QFont::initialize()
{
    // create global font cache
    if ( ! QFontCache::instance ) (void) new QFontCache;

#ifndef QT_NO_CODECS
#ifndef QT_NO_BIG_CODECS
    static bool codecs_once = FALSE;
    if ( ! codecs_once ) {
	(void) new QFontJis0201Codec;
	(void) new QFontJis0208Codec;
	(void) new QFontKsc5601Codec;
	(void) new QFontGb2312Codec;
	(void) new QFontGbkCodec;
	(void) new QFontGb18030_0Codec;
	(void) new QFontBig5Codec;
	(void) new QFontBig5hkscsCodec;
	(void) new QFontLaoCodec;
	codecs_once = TRUE;
    }
#endif // QT_NO_BIG_CODECS
#endif // QT_NO_CODECS

    extern int qt_encoding_id_for_mib( int mib ); // from qfontdatabase_x11.cpp
    QTextCodec *codec = QTextCodec::codecForLocale();
    // determine the default encoding id using the locale, otherwise
    // fallback to latin1 ( mib == 4 )
    int mib = codec ? codec->mibEnum() : 4;

    // for asian locales, use the mib for the font codec instead of the locale codec
    switch (mib) {
    case 38: // eucKR
	mib = 36;
	break;

    case 2025: // GB2312
	mib = 57;
	break;

    case 113: // GBK
	mib = -113;
	break;

    case 114: // GB18030
	mib = -114;
	break;

    case 2026: // Big5
	mib = -2026;
	break;

    case 2101: // Big5-HKSCS
	mib = -2101;
	break;

    case 16: // JIS7
	mib = 15;
	break;

    case 17: // SJIS
    case 18: // eucJP
	mib = 63;
	break;
    }

    // get the default encoding id for the locale encoding...
    QFontPrivate::defaultEncodingID = qt_encoding_id_for_mib( mib );

    // get some sample text based on the users locale. we use this to determine the
    // default script for the font system
    QCString oldlctime = setlocale(LC_TIME, 0);
    QCString lctime = setlocale(LC_TIME, "");

    time_t ttmp = time(0);
    struct tm *tt = 0;
    char samp[64];
    QString sample;

    if ( ttmp != -1 ) {
#if defined(QT_THREAD_SUPPORT) && defined(_POSIX_THREAD_SAFE_FUNCTIONS)
	// use the reentrant versions of localtime() where available
	tm res;
	tt = localtime_r( &ttmp, &res );
#else
	tt = localtime( &ttmp );
#endif // QT_THREAD_SUPPORT && _POSIX_THREAD_SAFE_FUNCTIONS

	if ( tt != 0 && strftime( samp, 64, "%A%B", tt ) > 0 )
	    if ( codec )
		sample = codec->toUnicode( samp );
    }

    if ( ! sample.isNull() && ! sample.isEmpty() ) {
	QFont::Script cs = QFont::NoScript, tmp;
	const QChar *uc = sample.unicode();
	QFontPrivate *priv = new QFontPrivate;

	for ( uint i = 0; i < sample.length(); i++ ) {
	    SCRIPT_FOR_CHAR( tmp, *uc );
	    uc++;
	    if ( tmp != cs && tmp != QFont::UnknownScript ) {
		cs = tmp;
		break;
	    }
	}
	delete priv;

	if ( cs != QFont::UnknownScript )
	    QFontPrivate::defaultScript = cs;
    }

    setlocale( LC_TIME, oldlctime.data() );
}

/*! \internal

  Internal function that cleans up the font system.
*/
void QFont::cleanup()
{
    // delete the global font cache
    delete QFontCache::instance;
}

/*!
  \internal
  X11 Only: Returns the screen with which this font is associated.
*/
int QFont::x11Screen() const
{
    return d->screen;
}

/*! \internal
    X11 Only: Associate the font with the specified \a screen.
*/
void QFont::x11SetScreen( int screen )
{
    if ( screen < 0 ) // assume default
	screen = QPaintDevice::x11AppScreen();

    if ( screen == d->screen )
	return; // nothing to do

    detach();
    d->screen = screen;
}

/*! \internal
    Returns a QFontEngine for the specified \a script that matches the
    QFontDef \e request member variable.
*/
void QFontPrivate::load( QFont::Script script )
{
    // NOTE: the X11 and Windows implementations of this function are
    // identical... if you change one, change both.

#ifdef QT_CHECK_STATE
    // sanity checks
    if (!QFontCache::instance)
	qWarning("Must construct a QApplication before a QFont");
    Q_ASSERT( script >= 0 && script < QFont::LastPrivateScript );
#endif // QT_CHECK_STATE

    QFontDef req = request;
    req.pixelSize = qRound(pixelSize(req, paintdevice, screen));
    req.pointSize = 0;

    if ( ! engineData ) {
	QFontCache::Key key( req, QFont::NoScript, screen, paintdevice );

	// look for the requested font in the engine data cache
	engineData = QFontCache::instance->findEngineData( key );

	if ( ! engineData ) {
	    // create a new one
	    engineData = new QFontEngineData;
	    QFontCache::instance->insertEngineData( key, engineData );
	} else {
	    engineData->ref();
	}
    }

    // the cached engineData could have already loaded the engine we want
    if ( engineData->engines[script] ) return;

    // load the font
    QFontEngine *engine = 0;
    //    double scale = 1.0; // ### TODO: fix the scale calculations

    // list of families to try
    QStringList family_list;

    if (!req.family.isEmpty()) {
	family_list = QStringList::split( ',', req.family );

	// append the substitute list for each family in family_list
	QStringList subs_list;
	QStringList::ConstIterator it = family_list.begin(), end = family_list.end();
	for ( ; it != end; ++it )
	    subs_list += QFont::substitutes( *it );
	family_list += subs_list;

#ifndef QT_XFT2
	// with Xft2, we want to use fontconfig to determine better fallbacks,
	// otherwise we might run into trouble with default fonts as "serif"

	// append the default fallback font for the specified script
	QString fallback = qt_fallback_font_family( script );
	if ( ! fallback.isEmpty() && ! family_list.contains( fallback ) )
	    family_list << fallback;

	// add the default family
	QString defaultFamily = QApplication::font().family();
	if ( ! family_list.contains( defaultFamily ) )
	    family_list << defaultFamily;

	// add QFont::defaultFamily() to the list, for compatibility with
	// previous versions
	family_list << QApplication::font().defaultFamily();
#endif // QT_XFT2
    }

    // null family means find the first font matching the specified script
    family_list << QString::null;

    QStringList::ConstIterator it = family_list.begin(), end = family_list.end();
    for ( ; ! engine && it != end; ++it ) {
	req.family = *it;

	engine = QFontDatabase::findFont( script, this, req );
	if ( engine ) {
	    if ( engine->type() != QFontEngine::Box )
		break;

	    if ( ! req.family.isEmpty() )
		engine = 0;

	    continue;
	}
    }

    engine->ref();
    engineData->engines[script] = engine;
}

/*!
    Returns TRUE if the font attributes have been changed and the font
    has to be (re)loaded; otherwise returns FALSE.
*/
bool QFont::dirty() const
{
    return d->engineData == 0;
}

/*!
    Returns the window system handle to the font, for low-level
    access. Using this function is \e not portable.
*/
Qt::HANDLE QFont::handle() const
{
    QFontEngine *engine = d->engineForScript( QFontPrivate::defaultScript );
#ifdef QT_CHECK_STATE
    Q_ASSERT( engine != 0 );
#endif // QT_CHECK_STATE

    switch ( engine->type() ) {
    case QFontEngine::XLFD:
	return ((QFontEngineXLFD *) engine)->handle();
    case QFontEngine::LatinXLFD:
	return ((QFontEngineLatinXLFD *) engine)->handle();

    default: break;
    }
    return 0;
}

/*!
    Returns the name of the font within the underlying window system.

    On Windows, this is usually just the family name of a TrueType
    font.

    On X11, it is an XLFD (X Logical Font Description).  When Qt is
    build with Xft support on X11, the return value can be an Xft
    pattern or an XLFD.

    Using the return value of this function is usually \e not \e
    portable.

    \sa setRawName()
*/
QString QFont::rawName() const
{
    QFontEngine *engine = d->engineForScript( QFontPrivate::defaultScript );
#ifdef QT_CHECK_STATE
    Q_ASSERT( engine != 0 );
#endif // QT_CHECK_STATE

    return QString::fromLatin1( engine->name() );
}

/*!
    Sets a font by its system specific name. The function is
    particularly useful under X, where system font settings (for
    example X resources) are usually available in XLFD (X Logical Font
    Description) form only. You can pass an XLFD as \a name to this
    function.

    A font set with setRawName() is still a full-featured QFont. It can
    be queried (for example with italic()) or modified (for example with
    setItalic()) and is therefore also suitable for rendering rich text.

    If Qt's internal font database cannot resolve the raw name, the
    font becomes a raw font with \a name as its family.

    Note that the present implementation does not handle wildcards in
    XLFDs well, and that font aliases (file \c fonts.alias in the font
    directory on X11) are not supported.

    \sa rawName(), setRawMode(), setFamily()
*/
void QFont::setRawName( const QString &name )
{
    detach();

    // from qfontdatabase_x11.cpp
    extern bool qt_fillFontDef( const QCString &xlfd, QFontDef *fd, int screen );

    if ( ! qt_fillFontDef( qt_fixXLFD( name.latin1() ), &d->request, d->screen ) ) {
#ifdef QT_CHECK_STATE
	qWarning("QFont::setRawName(): Invalid XLFD: \"%s\"", name.latin1());
#endif // QT_CHECK_STATE

	setFamily( name );
	setRawMode( TRUE );
    } else {
	d->mask = QFontPrivate::Complete;
    }
}

/*!
    Returns the "last resort" font family name.

    The current implementation tries a wide variety of common fonts,
    returning the first one it finds. Is is possible that no family is
    found in which case a null string is returned.

    \sa lastResortFont()
*/
QString QFont::lastResortFamily() const
{
    return QString::fromLatin1( "Helvetica" );
}

/*!
    Returns the family name that corresponds to the current style
    hint.

    \sa StyleHint styleHint() setStyleHint()
*/
QString QFont::defaultFamily() const
{
    switch ( d->request.styleHint ) {
    case QFont::Times:
	return QString::fromLatin1( "Times" );

    case QFont::Courier:
	return QString::fromLatin1( "Courier" );

    case QFont::Decorative:
	return QString::fromLatin1( "Old English" );

    case QFont::Helvetica:
    case QFont::System:
    default:
	return QString::fromLatin1( "Helvetica" );
    }
}

/*
  Returns a last resort raw font name for the font matching algorithm.
  This is used if even the last resort family is not available. It
  returns \e something, almost no matter what.  The current
  implementation tries a wide variety of common fonts, returning the
  first one it finds. The implementation may change at any time.
*/
static const char * const tryFonts[] = {
    "-*-helvetica-medium-r-*-*-*-120-*-*-*-*-*-*",
    "-*-courier-medium-r-*-*-*-120-*-*-*-*-*-*",
    "-*-times-medium-r-*-*-*-120-*-*-*-*-*-*",
    "-*-lucida-medium-r-*-*-*-120-*-*-*-*-*-*",
    "-*-helvetica-*-*-*-*-*-120-*-*-*-*-*-*",
    "-*-courier-*-*-*-*-*-120-*-*-*-*-*-*",
    "-*-times-*-*-*-*-*-120-*-*-*-*-*-*",
    "-*-lucida-*-*-*-*-*-120-*-*-*-*-*-*",
    "-*-helvetica-*-*-*-*-*-*-*-*-*-*-*-*",
    "-*-courier-*-*-*-*-*-*-*-*-*-*-*-*",
    "-*-times-*-*-*-*-*-*-*-*-*-*-*-*",
    "-*-lucida-*-*-*-*-*-*-*-*-*-*-*-*",
    "-*-fixed-*-*-*-*-*-*-*-*-*-*-*-*",
    "6x13",
    "7x13",
    "8x13",
    "9x15",
    "fixed",
    0
};

// Returns TRUE if the font exists, FALSE otherwise
static bool fontExists( const QString &fontName )
{
    int count;
    char **fontNames = XListFonts( QPaintDevice::x11AppDisplay(),
				   (char*)fontName.latin1(), 32768, &count );
    if ( fontNames ) XFreeFontNames( fontNames );

    return count != 0;
}

/*!
    Returns a "last resort" font name for the font matching algorithm.
    This is used if the last resort family is not available. It will
    always return a name, if necessary returning something like
    "fixed" or "system".

    The current implementation tries a wide variety of common fonts,
    returning the first one it finds. The implementation may change
    at any time, but this function will always return a string
    containing something.

    It is theoretically possible that there really isn't a
    lastResortFont() in which case Qt will abort with an error
    message. We have not been able to identify a case where this
    happens. Please \link bughowto.html report it as a bug\endlink if
    it does, preferably with a list of the fonts you have installed.

    \sa lastResortFamily() rawName()
*/
QString QFont::lastResortFont() const
{
    static QString last;

    // already found
    if ( ! last.isNull() )
	return last;

    int i = 0;
    const char* f;

    while ( ( f = tryFonts[i] ) ) {
	last = QString::fromLatin1( f );

	if ( fontExists( last ) )
	    return last;

	i++;
    }

#if defined(CHECK_NULL)
    qFatal( "QFontPrivate::lastResortFont: Cannot find any reasonable font" );
#endif

    return last;
}




// **********************************************************************
// QFontMetrics member methods
// **********************************************************************

int QFontMetrics::width( QChar ch ) const
{
    unsigned short uc = ch.unicode();
    if ( uc < QFontEngineData::widthCacheSize &&
	 d->engineData && d->engineData->widthCache[ uc ] )
	return d->engineData->widthCache[ uc ];

    if ( ::category( ch ) == QChar::Mark_NonSpacing || qIsZeroWidthChar(ch.unicode()))
	return 0;

    QFont::Script script;
    SCRIPT_FOR_CHAR( script, ch );

    QFontEngine *engine = d->engineForScript( script );
#ifdef QT_CHECK_STATE
    Q_ASSERT( engine != 0 );
#endif // QT_CHECK_STATE

    glyph_t glyphs[8];
    advance_t advances[8];
    int nglyphs = 7;
    engine->stringToCMap( &ch, 1, glyphs, advances, &nglyphs, FALSE );

    // ### can nglyphs != 1 happen at all? Not currently I think
    if ( uc < QFontEngineData::widthCacheSize && advances[0] > 0 && advances[0] < 0x100 )
	d->engineData->widthCache[ uc ] = advances[0];

    return advances[0];
}


int QFontMetrics::charWidth( const QString &str, int pos ) const
{
    if ( pos < 0 || pos > (int)str.length() )
	return 0;

    const QChar &ch = str.unicode()[ pos ];
    if ( ch.unicode() < QFontEngineData::widthCacheSize &&
	 d->engineData && d->engineData->widthCache[ ch.unicode() ] )
	return d->engineData->widthCache[ ch.unicode() ];

    QFont::Script script;
    SCRIPT_FOR_CHAR( script, ch );

    int width;

    if ( script >= QFont::Arabic && script <= QFont::Khmer ) {
	// complex script shaping. Have to do some hard work
	int from = QMAX( 0,  pos - 8 );
	int to = QMIN( (int)str.length(), pos + 8 );
	QConstString cstr( str.unicode()+from, to-from);
	QTextEngine layout( cstr.string(), d );
	layout.itemize( QTextEngine::WidthOnly );
	width = layout.width( pos-from, 1 );
    } else if ( ::category( ch ) == QChar::Mark_NonSpacing || qIsZeroWidthChar(ch.unicode())) {
        width = 0;
    } else {
	QFontEngine *engine = d->engineForScript( script );
#ifdef QT_CHECK_STATE
	Q_ASSERT( engine != 0 );
#endif // QT_CHECK_STATE

	glyph_t glyphs[8];
	advance_t advances[8];
	int nglyphs = 7;
	engine->stringToCMap( &ch, 1, glyphs, advances, &nglyphs, FALSE );
	width = advances[0];
    }
    if ( ch.unicode() < QFontEngineData::widthCacheSize && width > 0 && width < 0x100 )
	d->engineData->widthCache[ ch.unicode() ] = width;
    return width;
}