QTextureGlyphCache Class Reference

#include <qtextureglyphcache_p.h>

Inheritance diagram for QTextureGlyphCache:

Classes
struct	Coord
struct	GlyphAndSubPixelPosition

Public Functions
void	createCache (int width, int height)
virtual void	createTextureData (int width, int height)=0
void	fillInPendingGlyphs ()
virtual void	fillTexture (const Coord &coord, glyph_t glyph, QFixed subPixelPosition)=0
virtual int	glyphMargin () const
virtual int	glyphPadding () const
bool	isNull () const
virtual int	maxTextureHeight () const
virtual int	maxTextureWidth () const
bool	populate (QFontEngine *fontEngine, int numGlyphs, const glyph_t *glyphs, const QFixedPoint *positions)
	QTextureGlyphCache (QFontEngineGlyphCache::Type type, const QTransform &matrix)
void	resizeCache (int width, int height)
virtual void	resizeTextureData (int width, int height)=0
QFixed	subPixelPositionForX (QFixed x) const
QImage	textureMapForGlyph (glyph_t g, QFixed subPixelPosition) const
virtual	~QTextureGlyphCache ()
Public Functions inherited from QFontEngineGlyphCache
Type	cacheType () const
	QFontEngineGlyphCache (const QTransform &matrix, Type type)
virtual	~QFontEngineGlyphCache ()
Public Functions inherited from QSharedData
	QSharedData ()
	Constructs a QSharedData object with a reference count of 0. More...
	QSharedData (const QSharedData &)
	Constructs a QSharedData object with reference count 0. More...

Public Variables
QHash< GlyphAndSubPixelPosition, Coord >	coords
Public Variables inherited from QFontEngineGlyphCache
QTransform	m_transform
QFontEngineGlyphCache::Type	m_type
Public Variables inherited from QSharedData
QAtomicInt	ref

Protected Functions
int	calculateSubPixelPositionCount (glyph_t) const

Protected Variables
QFontEngine *	m_current_fontengine
int	m_currentRowHeight
int	m_cx
int	m_cy
int	m_h
QHash< GlyphAndSubPixelPosition, Coord >	m_pendingGlyphs
int	m_subPixelPositionCount
int	m_w

Additional Inherited Members
Public Types inherited from QFontEngineGlyphCache
enum	Type { Raster_RGBMask, Raster_A8, Raster_Mono }

Detailed Description

Definition at line 79 of file qtextureglyphcache_p.h.

Constructors and Destructors

QTextureGlyphCache()

QTextureGlyphCache::QTextureGlyphCache ( QFontEngineGlyphCache::Type  type, const QTransform &  matrix  )

inline

Definition at line 82 of file qtextureglyphcache_p.h.

        : QFontEngineGlyphCache(matrix, type), m_current_fontengine(0),
                                               m_w(0), m_h(0), m_cx(0), m_cy(0), m_currentRowHeight(0), m_subPixelPositionCount(0)
        { }

~QTextureGlyphCache()

virtual QTextureGlyphCache::~QTextureGlyphCache ( )

inlinevirtual

Definition at line 87 of file qtextureglyphcache_p.h.

{ }

Functions

calculateSubPixelPositionCount()

int QTextureGlyphCache::calculateSubPixelPositionCount ( glyph_t  glyph ) const

protected

Definition at line 68 of file qtextureglyphcache.cpp.

Referenced by populate().

{
    // Test 12 different subpixel positions since it factors into 3*4 so it gives
    // the coverage we need.

    QList<QImage> images;
    for (int i=0; i<12; ++i) {
        QImage img = textureMapForGlyph(glyph, QFixed::fromReal(i / 12.0));

        if (images.isEmpty()) {
            QPainterPath path;
            QFixedPoint point;
            m_current_fontengine->addGlyphsToPath(&glyph, &point, 1, &path, QTextItem::RenderFlags());

            // Glyph is space, return 0 to indicate that we need to keep trying
            if (path.isEmpty())
                break;

            images.append(img);
        } else {
            bool found = false;
            for (int j=0; j<images.size(); ++j) {
                if (images.at(j) == img) {
                    found = true;
                    break;
                }
            }
            if (!found)
                images.append(img);
        }
    }

    return images.size();
}

createCache()

void QTextureGlyphCache::createCache ( int  width, int  height  )

inline

Definition at line 128 of file qtextureglyphcache_p.h.

Referenced by fillInPendingGlyphs().

                                                   {
        m_w = width;
        m_h = height;
        createTextureData(width, height);
    }

createTextureData()

virtual void QTextureGlyphCache::createTextureData ( int  width, int  height  )

pure virtual

Implemented in QImageTextureGlyphCache, and QGLTextureGlyphCache.

fillInPendingGlyphs()

void QTextureGlyphCache::fillInPendingGlyphs

(

)

Definition at line 259 of file qtextureglyphcache.cpp.

Referenced by QGL2PaintEngineExPrivate::drawCachedGlyphs(), and QRasterPaintEngine::drawCachedGlyphs().

{
    if (m_pendingGlyphs.isEmpty())
        return;

    int requiredHeight = m_h;
    int requiredWidth = m_w; // Use a minimum size to avoid a lot of initial reallocations
    {
        QHash<GlyphAndSubPixelPosition, Coord>::iterator iter = m_pendingGlyphs.begin();
        while (iter != m_pendingGlyphs.end()) {
            Coord c = iter.value();
            requiredHeight = qMax(requiredHeight, c.y + c.h);
            requiredWidth = qMax(requiredWidth, c.x + c.w);
            ++iter;
        }
    }

    if (isNull() || requiredHeight > m_h || requiredWidth > m_w) {
        if (isNull())
            createCache(qt_next_power_of_two(requiredWidth), qt_next_power_of_two(requiredHeight));
        else
            resizeCache(qt_next_power_of_two(requiredWidth), qt_next_power_of_two(requiredHeight));
    }

    {
        QHash<GlyphAndSubPixelPosition, Coord>::iterator iter = m_pendingGlyphs.begin();
        while (iter != m_pendingGlyphs.end()) {
            GlyphAndSubPixelPosition key = iter.key();
            fillTexture(iter.value(), key.glyph, key.subPixelPosition);

            ++iter;
        }
    }

    m_pendingGlyphs.clear();
}

fillTexture()

virtual void QTextureGlyphCache::fillTexture ( const Coord &  coord, glyph_t  glyph, QFixed  subPixelPosition  )

pure virtual

Implemented in QImageTextureGlyphCache, and QGLTextureGlyphCache.

Referenced by fillInPendingGlyphs().

glyphMargin()

virtual int QTextureGlyphCache::glyphMargin ( ) const

inlinevirtual

Reimplemented in QImageTextureGlyphCache.

Definition at line 123 of file qtextureglyphcache_p.h.

Referenced by QImageTextureGlyphCache::fillTexture(), populate(), and textureMapForGlyph().

{ return 0; }

glyphPadding()

virtual int QTextureGlyphCache::glyphPadding ( ) const

inlinevirtual

Reimplemented in QGLTextureGlyphCache.

Definition at line 124 of file qtextureglyphcache_p.h.

Referenced by populate().

{ return 0; }

isNull()

bool QTextureGlyphCache::isNull ( ) const

inline

Definition at line 141 of file qtextureglyphcache_p.h.

Referenced by QGLTextureGlyphCache::createTextureData(), and fillInPendingGlyphs().

{ return m_h == 0; }

maxTextureHeight()

virtual int QTextureGlyphCache::maxTextureHeight ( ) const

inlinevirtual

Reimplemented in QGLTextureGlyphCache.

Definition at line 145 of file qtextureglyphcache_p.h.

Referenced by QGLTextureGlyphCache::maxTextureHeight(), and populate().

{ return -1; }

maxTextureWidth()

virtual int QTextureGlyphCache::maxTextureWidth ( ) const

inlinevirtual

Reimplemented in QGLTextureGlyphCache.

Definition at line 144 of file qtextureglyphcache_p.h.

Referenced by QGLTextureGlyphCache::maxTextureWidth(), and populate().

{ return QT_DEFAULT_TEXTURE_GLYPH_CACHE_WIDTH; }

populate()

bool QTextureGlyphCache::populate	(	QFontEngine *	fontEngine,
		int	numGlyphs,
		const glyph_t *	glyphs,
		const QFixedPoint *	positions
	)

Definition at line 120 of file qtextureglyphcache.cpp.

Referenced by QGL2PaintEngineExPrivate::drawCachedGlyphs(), and QRasterPaintEngine::drawCachedGlyphs().

{
#ifdef CACHE_DEBUG
    printf("Populating with %d glyphs\n", numGlyphs);
    qDebug() << " -> current transformation: " << m_transform;
#endif

    m_current_fontengine = fontEngine;
    const int margin = glyphMargin();
    const int paddingDoubled = glyphPadding() * 2;

    bool supportsSubPixelPositions = fontEngine->supportsSubPixelPositions();
    if (m_subPixelPositionCount == 0) {
        if (!supportsSubPixelPositions) {
            m_subPixelPositionCount = 1;
        } else {
#if !defined(Q_WS_X11)
            int i = 0;
            while (m_subPixelPositionCount == 0 && i < numGlyphs)
                m_subPixelPositionCount = calculateSubPixelPositionCount(glyphs[i++]);
#else
            m_subPixelPositionCount = 4;
#endif
        }
    }

    QHash<GlyphAndSubPixelPosition, Coord> listItemCoordinates;
    int rowHeight = 0;

    QFontEngine::GlyphFormat format;
    switch (m_type) {
    case Raster_A8: format = QFontEngine::Format_A8; break;
    case Raster_RGBMask: format = QFontEngine::Format_A32; break;
    default: format = QFontEngine::Format_Mono; break;
    }

    // check each glyph for its metrics and get the required rowHeight.
    for (int i=0; i < numGlyphs; ++i) {
        const glyph_t glyph = glyphs[i];

        QFixed subPixelPosition;
        if (supportsSubPixelPositions) {
            QFixed x = positions != 0 ? positions[i].x : QFixed();
            subPixelPosition = subPixelPositionForX(x);
        }

        if (coords.contains(GlyphAndSubPixelPosition(glyph, subPixelPosition)))
            continue;
        if (listItemCoordinates.contains(GlyphAndSubPixelPosition(glyph, subPixelPosition)))
            continue;
        glyph_metrics_t metrics = fontEngine->alphaMapBoundingBox(glyph, subPixelPosition, m_transform, format);

#ifdef CACHE_DEBUG
        printf("(%4x): w=%.2f, h=%.2f, xoff=%.2f, yoff=%.2f, x=%.2f, y=%.2f\n",
               glyph,
               metrics.width.toReal(),
               metrics.height.toReal(),
               metrics.xoff.toReal(),
               metrics.yoff.toReal(),
               metrics.x.toReal(),
               metrics.y.toReal());
#endif        
        GlyphAndSubPixelPosition key(glyph, subPixelPosition);
        int glyph_width = metrics.width.ceil().toInt();
        int glyph_height = metrics.height.ceil().toInt();
        if (glyph_height == 0 || glyph_width == 0) {
            // Avoid multiple calls to boundingBox() for non-printable characters
            Coord c = { 0, 0, 0, 0, 0, 0 };
            coords.insert(key, c);
            continue;
        }
        glyph_width += margin * 2 + 4;
        glyph_height += margin * 2 + 4;
        // align to 8-bit boundary
        if (m_type == QFontEngineGlyphCache::Raster_Mono)
            glyph_width = (glyph_width+7)&~7;

        Coord c = { 0, 0, // will be filled in later
                    glyph_width,
                    glyph_height, // texture coords
                    metrics.x.truncate(),
                    -metrics.y.truncate() }; // baseline for horizontal scripts

        listItemCoordinates.insert(key, c);
        rowHeight = qMax(rowHeight, glyph_height);
    }
    if (listItemCoordinates.isEmpty())
        return true;

    rowHeight += margin * 2 + paddingDoubled;

    if (m_w == 0) {
        if (fontEngine->maxCharWidth() <= QT_DEFAULT_TEXTURE_GLYPH_CACHE_WIDTH)
            m_w = QT_DEFAULT_TEXTURE_GLYPH_CACHE_WIDTH;
        else
            m_w = qt_next_power_of_two(fontEngine->maxCharWidth());
    }

    // now actually use the coords and paint the wanted glyps into cache.
    QHash<GlyphAndSubPixelPosition, Coord>::iterator iter = listItemCoordinates.begin();
    int requiredWidth = m_w;
    while (iter != listItemCoordinates.end()) {
        Coord c = iter.value();

        m_currentRowHeight = qMax(m_currentRowHeight, c.h + margin * 2);

        if (m_cx + c.w > requiredWidth) {
            int new_width = requiredWidth*2;
            while (new_width < m_cx + c.w)
                new_width *= 2;
            if (new_width <= maxTextureWidth()) {
                requiredWidth = new_width;
            } else {
                // no room on the current line, start new glyph strip
                m_cx = 0;
                m_cy += m_currentRowHeight + paddingDoubled;
                m_currentRowHeight = c.h + margin * 2; // New row
            }
        }

        if (maxTextureHeight() > 0 && m_cy + c.h > maxTextureHeight()) {
            // We can't make a cache of the required size, so we bail out
            return false;
        }

        c.x = m_cx;
        c.y = m_cy;

        coords.insert(iter.key(), c);
        m_pendingGlyphs.insert(iter.key(), c);

        m_cx += c.w + paddingDoubled;
        ++iter;
    }
    return true;

}

resizeCache()

void QTextureGlyphCache::resizeCache ( int  width, int  height  )

inline

Definition at line 134 of file qtextureglyphcache_p.h.

Referenced by fillInPendingGlyphs().

    {
        resizeTextureData(width, height);
        m_w = width;
        m_h = height;
    }

resizeTextureData()

virtual void QTextureGlyphCache::resizeTextureData ( int  width, int  height  )

pure virtual

Implemented in QImageTextureGlyphCache, and QGLTextureGlyphCache.

subPixelPositionForX()

QFixed QTextureGlyphCache::subPixelPositionForX

(

QFixed

x

)

const

Definition at line 103 of file qtextureglyphcache.cpp.

Referenced by QGL2PaintEngineExPrivate::drawCachedGlyphs(), QRasterPaintEngine::drawCachedGlyphs(), and populate().

{
    if (m_subPixelPositionCount <= 1)
        return QFixed();

    QFixed subPixelPosition;
    if (x != 0) {
        subPixelPosition = x - x.floor();
        QFixed fraction = (subPixelPosition / QFixed::fromReal(1.0 / m_subPixelPositionCount)).floor();

        // Compensate for precision loss in fixed point to make sure we are always drawing at a subpixel position over
        // the lower boundary for the selected rasterization by adding 1/64.
        subPixelPosition = fraction / QFixed(m_subPixelPositionCount) + QFixed::fromReal(0.015625);
    }
    return subPixelPosition;
}

textureMapForGlyph()

QImage QTextureGlyphCache::textureMapForGlyph	(	glyph_t	g,
		QFixed	subPixelPosition
	)		const

Definition at line 296 of file qtextureglyphcache.cpp.

Referenced by calculateSubPixelPositionCount(), QGLTextureGlyphCache::fillTexture(), and QImageTextureGlyphCache::fillTexture().

{
#if defined(Q_WS_X11)
    if (m_type != Raster_RGBMask && m_transform.type() > QTransform::TxTranslate && m_current_fontengine->type() == QFontEngine::Freetype) {
        QFontEngineFT::GlyphFormat format = QFontEngineFT::Format_None;
        QImage::Format imageFormat = QImage::Format_Invalid;
        switch (m_type) {
        case Raster_A8:
            format = QFontEngineFT::Format_A8;
            imageFormat = QImage::Format_Indexed8;
            break;
        case Raster_Mono:
            format = QFontEngineFT::Format_Mono;
            imageFormat = QImage::Format_Mono;
            break;
        case Raster_RGBMask:
            // impossible condition (see the if-clause above)
            // this option is here only to silence a compiler warning
            break;
        };

        QFontEngineFT *ft = static_cast<QFontEngineFT*> (m_current_fontengine);
        QFontEngineFT::QGlyphSet *gset = ft->loadTransformedGlyphSet(m_transform);
        QFixedPoint positions[1];
        positions[0].x = subPixelPosition;

        if (gset && ft->loadGlyphs(gset, &g, 1, positions, format)) {
            QFontEngineFT::Glyph *glyph = gset->getGlyph(g, subPixelPosition);
            const int bytesPerLine = (format == QFontEngineFT::Format_Mono ? ((glyph->width + 31) & ~31) >> 3
                               : (glyph->width + 3) & ~3);
            return QImage(glyph->data, glyph->width, glyph->height, bytesPerLine, imageFormat);
        }
    } else
#endif
    if (m_type == QFontEngineGlyphCache::Raster_RGBMask)
        return m_current_fontengine->alphaRGBMapForGlyph(g, subPixelPosition, glyphMargin(), m_transform);
    else
        return m_current_fontengine->alphaMapForGlyph(g, subPixelPosition, m_transform);

    return QImage();
}

Properties

coords

QHash<GlyphAndSubPixelPosition, Coord> QTextureGlyphCache::coords

Definition at line 143 of file qtextureglyphcache_p.h.

Referenced by QGLTextureGlyphCache::clear(), QGL2PaintEngineExPrivate::drawCachedGlyphs(), QRasterPaintEngine::drawCachedGlyphs(), and populate().

m_current_fontengine

QFontEngine* QTextureGlyphCache::m_current_fontengine

protected

Definition at line 154 of file qtextureglyphcache_p.h.

Referenced by calculateSubPixelPositionCount(), populate(), and textureMapForGlyph().

m_currentRowHeight

int QTextureGlyphCache::m_currentRowHeight

protected

Definition at line 161 of file qtextureglyphcache_p.h.

Referenced by QGLTextureGlyphCache::clear(), and populate().

m_cx

int QTextureGlyphCache::m_cx

protected

Definition at line 159 of file qtextureglyphcache_p.h.

Referenced by QGLTextureGlyphCache::clear(), and populate().

m_cy

int QTextureGlyphCache::m_cy

protected

Definition at line 160 of file qtextureglyphcache_p.h.

Referenced by QGLTextureGlyphCache::clear(), and populate().

m_h

int QTextureGlyphCache::m_h

protected

Definition at line 158 of file qtextureglyphcache_p.h.

Referenced by QGLTextureGlyphCache::clear(), fillInPendingGlyphs(), and QGLTextureGlyphCache::setContext().

m_pendingGlyphs

QHash<GlyphAndSubPixelPosition, Coord> QTextureGlyphCache::m_pendingGlyphs

protected

Definition at line 155 of file qtextureglyphcache_p.h.

Referenced by fillInPendingGlyphs(), and populate().

m_subPixelPositionCount

int QTextureGlyphCache::m_subPixelPositionCount

protected

Definition at line 162 of file qtextureglyphcache_p.h.

Referenced by populate(), and subPixelPositionForX().

m_w

int QTextureGlyphCache::m_w

protected

Definition at line 157 of file qtextureglyphcache_p.h.

Referenced by QGLTextureGlyphCache::clear(), fillInPendingGlyphs(), and populate().

---

The documentation for this class was generated from the following files:

• /src/gui/painting/qtextureglyphcache_p.h
• /src/gui/painting/qtextureglyphcache.cpp