qwt_text.cpp

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/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#include "qwt_text.h"
#include "qwt_painter.h"
#include "qwt_text_engine.h"
#include <qmap.h>
#include <qfont.h>
#include <qcolor.h>
#include <qpen.h>
#include <qbrush.h>
#include <qpainter.h>
#include <qapplication.h>
#include <qdesktopwidget.h>
#include <qmath.h>

class QwtTextEngineDict
{
public:
    static QwtTextEngineDict &dict();

    void setTextEngine( QwtText::TextFormat, QwtTextEngine * );

    const QwtTextEngine *textEngine( QwtText::TextFormat ) const;
    const QwtTextEngine *textEngine( const QString &,
        QwtText::TextFormat ) const;

private:
    QwtTextEngineDict();
    ~QwtTextEngineDict();

    typedef QMap<int, QwtTextEngine *> EngineMap;

    inline const QwtTextEngine *engine( EngineMap::const_iterator &it ) const
    {
        return it.value();
    }

    EngineMap d_map;
};

QwtTextEngineDict &QwtTextEngineDict::dict()
{
    static QwtTextEngineDict engineDict;
    return engineDict;
}

QwtTextEngineDict::QwtTextEngineDict()
{
    d_map.insert( QwtText::PlainText, new QwtPlainTextEngine() );
#ifndef QT_NO_RICHTEXT
    d_map.insert( QwtText::RichText, new QwtRichTextEngine() );
#endif
}

QwtTextEngineDict::~QwtTextEngineDict()
{
    for ( EngineMap::const_iterator it = d_map.begin();
        it != d_map.end(); ++it )
    {
        const QwtTextEngine *textEngine = engine( it );
        delete textEngine;
    }
}

const QwtTextEngine *QwtTextEngineDict::textEngine( const QString& text,
    QwtText::TextFormat format ) const
{
    if ( format == QwtText::AutoText )
    {
        for ( EngineMap::const_iterator it = d_map.begin();
            it != d_map.end(); ++it )
        {
            if ( it.key() != QwtText::PlainText )
            {
                const QwtTextEngine *e = engine( it );
                if ( e && e->mightRender( text ) )
                    return e;
            }
        }
    }

    EngineMap::const_iterator it = d_map.find( format );
    if ( it != d_map.end() )
    {
        const QwtTextEngine *e = engine( it );
        if ( e )
            return e;
    }

    it = d_map.find( QwtText::PlainText );
    return engine( it );
}

void QwtTextEngineDict::setTextEngine( QwtText::TextFormat format,
    QwtTextEngine *engine )
{
    if ( format == QwtText::AutoText )
        return;

    if ( format == QwtText::PlainText && engine == NULL )
        return;

    EngineMap::const_iterator it = d_map.find( format );
    if ( it != d_map.end() )
    {
        const QwtTextEngine *e = this->engine( it );
        if ( e )
            delete e;

        d_map.remove( format );
    }

    if ( engine != NULL )
        d_map.insert( format, engine );
}

const QwtTextEngine *QwtTextEngineDict::textEngine(
    QwtText::TextFormat format ) const
{
    const QwtTextEngine *e = NULL;

    EngineMap::const_iterator it = d_map.find( format );
    if ( it != d_map.end() )
        e = engine( it );

    return e;
}

class QwtText::PrivateData
{
public:
    PrivateData():
        renderFlags( Qt::AlignCenter ),
        borderRadius( 0 ),
        borderPen( Qt::NoPen ),
        backgroundBrush( Qt::NoBrush ),
        paintAttributes( 0 ),
        layoutAttributes( 0 ),
        textEngine( NULL )
    {
    }

    int renderFlags;
    QString text;
    QFont font;
    QColor color;
    double borderRadius;
    QPen borderPen;
    QBrush backgroundBrush;

    QwtText::PaintAttributes paintAttributes;
    QwtText::LayoutAttributes layoutAttributes;

    const QwtTextEngine *textEngine;
};

class QwtText::LayoutCache
{
public:
    void invalidate()
    {
        textSize = QSizeF();
    }

    QFont font;
    QSizeF textSize;
};

QwtText::QwtText( const QString &text, QwtText::TextFormat textFormat )
{
    d_data = new PrivateData;
    d_data->text = text;
    d_data->textEngine = textEngine( text, textFormat );

    d_layoutCache = new LayoutCache;
}

QwtText::QwtText( const QwtText &other )
{
    d_data = new PrivateData;
    *d_data = *other.d_data;

    d_layoutCache = new LayoutCache;
    *d_layoutCache = *other.d_layoutCache;
}

QwtText::~QwtText()
{
    delete d_data;
    delete d_layoutCache;
}

QwtText &QwtText::operator=( const QwtText & other )
{
    *d_data = *other.d_data;
    *d_layoutCache = *other.d_layoutCache;
    return *this;
}

bool QwtText::operator==( const QwtText &other ) const
{
    return d_data->renderFlags == other.d_data->renderFlags &&
        d_data->text == other.d_data->text &&
        d_data->font == other.d_data->font &&
        d_data->color == other.d_data->color &&
        d_data->borderRadius == other.d_data->borderRadius &&
        d_data->borderPen == other.d_data->borderPen &&
        d_data->backgroundBrush == other.d_data->backgroundBrush &&
        d_data->paintAttributes == other.d_data->paintAttributes &&
        d_data->textEngine == other.d_data->textEngine;
}

bool QwtText::operator!=( const QwtText &other ) const // invalidate
{
    return !( other == *this );
}

void QwtText::setText( const QString &text,
    QwtText::TextFormat textFormat )
{
    d_data->text = text;
    d_data->textEngine = textEngine( text, textFormat );
    d_layoutCache->invalidate();
}

QString QwtText::text() const
{
    return d_data->text;
}

void QwtText::setRenderFlags( int renderFlags )
{
    if ( renderFlags != d_data->renderFlags )
    {
        d_data->renderFlags = renderFlags;
        d_layoutCache->invalidate();
    }
}

int QwtText::renderFlags() const
{
    return d_data->renderFlags;
}

void QwtText::setFont( const QFont &font )
{
    d_data->font = font;
    setPaintAttribute( PaintUsingTextFont );
}

QFont QwtText::font() const
{
    return d_data->font;
}

QFont QwtText::usedFont( const QFont &defaultFont ) const
{
    if ( d_data->paintAttributes & PaintUsingTextFont )
        return d_data->font;

    return defaultFont;
}

void QwtText::setColor( const QColor &color )
{
    d_data->color = color;
    setPaintAttribute( PaintUsingTextColor );
}

QColor QwtText::color() const
{
    return d_data->color;
}

QColor QwtText::usedColor( const QColor &defaultColor ) const
{
    if ( d_data->paintAttributes & PaintUsingTextColor )
        return d_data->color;

    return defaultColor;
}

void QwtText::setBorderRadius( double radius )
{
    d_data->borderRadius = qMax( 0.0, radius );
}

double QwtText::borderRadius() const
{
    return d_data->borderRadius;
}

void QwtText::setBorderPen( const QPen &pen )
{
    d_data->borderPen = pen;
    setPaintAttribute( PaintBackground );
}

QPen QwtText::borderPen() const
{
    return d_data->borderPen;
}

void QwtText::setBackgroundBrush( const QBrush &brush )
{
    d_data->backgroundBrush = brush;
    setPaintAttribute( PaintBackground );
}

QBrush QwtText::backgroundBrush() const
{
    return d_data->backgroundBrush;
}

void QwtText::setPaintAttribute( PaintAttribute attribute, bool on )
{
    if ( on )
        d_data->paintAttributes |= attribute;
    else
        d_data->paintAttributes &= ~attribute;
}

bool QwtText::testPaintAttribute( PaintAttribute attribute ) const
{
    return d_data->paintAttributes & attribute;
}

void QwtText::setLayoutAttribute( LayoutAttribute attribute, bool on )
{
    if ( on )
        d_data->layoutAttributes |= attribute;
    else
        d_data->layoutAttributes &= ~attribute;
}

bool QwtText::testLayoutAttribute( LayoutAttribute attribute ) const
{
    return d_data->layoutAttributes | attribute;
}

double QwtText::heightForWidth( double width, const QFont &defaultFont ) const
{
    // We want to calculate in screen metrics. So
    // we need a font that uses screen metrics

    const QFont font( usedFont( defaultFont ), QApplication::desktop() );

    double h = 0;

    if ( d_data->layoutAttributes & MinimumLayout )
    {
        double left, right, top, bottom;
        d_data->textEngine->textMargins( font, d_data->text,
            left, right, top, bottom );

        h = d_data->textEngine->heightForWidth(
            font, d_data->renderFlags, d_data->text,
            width + left + right );

        h -= top + bottom;
    }
    else
    {
        h = d_data->textEngine->heightForWidth(
            font, d_data->renderFlags, d_data->text, width );
    }

    return h;
}

QSizeF QwtText::textSize( const QFont &defaultFont ) const
{
    // We want to calculate in screen metrics. So
    // we need a font that uses screen metrics

    const QFont font( usedFont( defaultFont ), QApplication::desktop() );

    if ( !d_layoutCache->textSize.isValid()
        || d_layoutCache->font != font )
    {
        d_layoutCache->textSize = d_data->textEngine->textSize(
            font, d_data->renderFlags, d_data->text );
        d_layoutCache->font = font;
    }

    QSizeF sz = d_layoutCache->textSize;

    if ( d_data->layoutAttributes & MinimumLayout )
    {
        double left, right, top, bottom;
        d_data->textEngine->textMargins( font, d_data->text,
            left, right, top, bottom );
        sz -= QSizeF( left + right, top + bottom );
    }

    return sz;
}

void QwtText::draw( QPainter *painter, const QRectF &rect ) const
{
    if ( d_data->paintAttributes & PaintBackground )
    {
        if ( d_data->borderPen != Qt::NoPen ||
            d_data->backgroundBrush != Qt::NoBrush )
        {
            painter->save();

            painter->setPen( d_data->borderPen );
            painter->setBrush( d_data->backgroundBrush );

            if ( d_data->borderRadius == 0 )
            {
                QwtPainter::drawRect( painter, rect );
            }
            else
            {
                painter->setRenderHint( QPainter::Antialiasing, true );
                painter->drawRoundedRect( rect,
                    d_data->borderRadius, d_data->borderRadius );
            }

            painter->restore();
        }
    }

    painter->save();

    if ( d_data->paintAttributes & PaintUsingTextFont )
    {
        painter->setFont( d_data->font );
    }

    if ( d_data->paintAttributes & PaintUsingTextColor )
    {
        if ( d_data->color.isValid() )
            painter->setPen( d_data->color );
    }

    QRectF expandedRect = rect;
    if ( d_data->layoutAttributes & MinimumLayout )
    {
        // We want to calculate in screen metrics. So
        // we need a font that uses screen metrics

        const QFont font( painter->font(), QApplication::desktop() );

        double left, right, top, bottom;
        d_data->textEngine->textMargins(
            font, d_data->text, left, right, top, bottom );

        expandedRect.setTop( rect.top() - top );
        expandedRect.setBottom( rect.bottom() + bottom );
        expandedRect.setLeft( rect.left() - left );
        expandedRect.setRight( rect.right() + right );
    }

    d_data->textEngine->draw( painter, expandedRect,
        d_data->renderFlags, d_data->text );

    painter->restore();
}

const QwtTextEngine *QwtText::textEngine( const QString &text,
    QwtText::TextFormat format )
{
    return QwtTextEngineDict::dict().textEngine( text, format );
}

void QwtText::setTextEngine( QwtText::TextFormat format,
    QwtTextEngine *engine )
{
    QwtTextEngineDict::dict().setTextEngine( format, engine );
}

const QwtTextEngine *QwtText::textEngine( QwtText::TextFormat format )
{
    return  QwtTextEngineDict::dict().textEngine( format );
}