qwt_text_label.cpp

/* -*- 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
 *****************************************************************************/

// vim: expandtab

#include <qpainter.h>
#include <qevent.h>
#include "qwt_text.h"
#include "qwt_painter.h"
#include "qwt_text_label.h"

class QwtTextLabel::PrivateData
{
public:
    PrivateData():
        indent(4),
        margin(0)
    {
    }

    int indent;
    int margin;
    QwtText text;
};

/*! 
  Constructs an empty label.
  \param parent Parent widget
*/
QwtTextLabel::QwtTextLabel(QWidget *parent):
    QFrame(parent)
{
    init();
}

#if QT_VERSION < 0x040000
/*! 
  Constructs an empty label.
  \param parent Parent widget
  \param name Object name
*/
QwtTextLabel::QwtTextLabel(QWidget *parent, const char *name):
    QFrame(parent, name)
{
    init();
}
#endif

/*!
  Constructs a label that displays the text, text
  \param parent Parent widget
  \param text Text
*/
QwtTextLabel::QwtTextLabel(const QwtText &text, QWidget *parent):
    QFrame(parent)
{
    init();
    d_data->text = text;
}

//! Destructor
QwtTextLabel::~QwtTextLabel()
{
    delete d_data;
}

void QwtTextLabel::init()
{
    d_data = new PrivateData();
    setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
}

/*!
   Change the label's text, keeping all other QwtText attributes
   \param text New text
   \param textFormat Format of text

  \sa QwtText
*/
void QwtTextLabel::setText(const QString &text, QwtText::TextFormat textFormat)
{
    d_data->text.setText(text, textFormat);

    update();
    updateGeometry();
}

/*!
   Change the label's text
   \param text New text
*/
void QwtTextLabel::setText(const QwtText &text)
{
    d_data->text = text;

    update();
    updateGeometry();
}

//! Return the text
const QwtText &QwtTextLabel::text() const
{
    return d_data->text;
}

//! Clear the text and all QwtText attributes
void QwtTextLabel::clear()
{
    d_data->text = QwtText();

    update();
    updateGeometry();
}

//! Return label's text indent in pixels
int QwtTextLabel::indent() const
{
    return d_data->indent;
}

/*!
  Set label's text indent in pixels
  \param indent Indentation in pixels
*/
void QwtTextLabel::setIndent(int indent)
{
    if ( indent < 0 )
        indent = 0;

    d_data->indent = indent;

    update();
    updateGeometry();
}

//! Return label's text indent in pixels
int QwtTextLabel::margin() const
{
    return d_data->margin;
}

/*!
  Set label's margin in pixels
  \param margin Margin in pixels
*/
void QwtTextLabel::setMargin(int margin)
{
    d_data->margin = margin;

    update();
    updateGeometry();
}

//! Return label's margin in pixels
QSize QwtTextLabel::sizeHint() const
{
    return minimumSizeHint();
}

//! Return a minimum size hint
QSize QwtTextLabel::minimumSizeHint() const
{
    QSize sz = d_data->text.textSize(font());

    int mw = 2 * (frameWidth() + d_data->margin);
    int mh = mw;

    int indent = d_data->indent;
    if ( indent <= 0 )
        indent = defaultIndent();

    if ( indent > 0 )
    {
        const int align = d_data->text.renderFlags();
        if ( align & Qt::AlignLeft || align & Qt::AlignRight )
            mw += d_data->indent;
        else if ( align & Qt::AlignTop || align & Qt::AlignBottom )
            mh += d_data->indent;
    }
        
    sz += QSize(mw, mh);

    return sz;
}

/*!
   Returns the preferred height for this widget, given the width.
   \param width Width
*/
int QwtTextLabel::heightForWidth(int width) const
{
    const int renderFlags = d_data->text.renderFlags();

    int indent = d_data->indent;
    if ( indent <= 0 )
        indent = defaultIndent();

    width -= 2 * frameWidth();
    if ( renderFlags & Qt::AlignLeft || renderFlags & Qt::AlignRight )
        width -= indent;

    int height = d_data->text.heightForWidth(width, font());
    if ( renderFlags & Qt::AlignTop || renderFlags & Qt::AlignBottom )
        height += indent;

    height += 2 * frameWidth();

    return height;
}

//! Qt paint event
void QwtTextLabel::paintEvent(QPaintEvent *event)
{
#if QT_VERSION >= 0x040000
    QPainter painter(this);

    if ( !contentsRect().contains( event->rect() ) )
    {
        painter.save();
        painter.setClipRegion( event->region() & frameRect() );
        drawFrame( &painter );
        painter.restore();
    }

    painter.setClipRegion(event->region() & contentsRect());

    drawContents( &painter );
#else // QT_VERSION < 0x040000
    QFrame::paintEvent(event);
#endif

}

//! Redraw the text and focus indicator
void QwtTextLabel::drawContents(QPainter *painter)
{
    const QRect r = textRect();
    if ( r.isEmpty() )
        return;

    painter->setFont(font());
#if QT_VERSION < 0x040000
    painter->setPen(palette().color(QPalette::Active, QColorGroup::Text));
#else
    painter->setPen(palette().color(QPalette::Active, QPalette::Text));
#endif

    drawText(painter, r);

    if ( hasFocus() )
    {
        const int margin = 2;

        QRect focusRect = contentsRect();
        focusRect.setRect(focusRect.x() + margin, focusRect.y() + margin,
            focusRect.width() - 2 * margin - 2, 
            focusRect.height() - 2 * margin - 2);

        QwtPainter::drawFocusRect(painter, this, focusRect);
    }
}

//! Redraw the text
void QwtTextLabel::drawText(QPainter *painter, const QRect &textRect)
{
    d_data->text.draw(painter, textRect);
}

/*! 
  Calculate the rect for the text in widget coordinates
  \return Text rect
*/
QRect QwtTextLabel::textRect() const
{
    QRect r = contentsRect();

    if ( !r.isEmpty() && d_data->margin > 0 )
    {
        r.setRect(r.x() + d_data->margin, r.y() + d_data->margin,
            r.width() - 2 * d_data->margin, r.height() - 2 * d_data->margin );
    }

    if ( !r.isEmpty() )
    {
        int indent = d_data->indent;
        if ( indent <= 0 )
            indent = defaultIndent();

        if ( indent > 0 )
        {
            const int renderFlags = d_data->text.renderFlags();

            if ( renderFlags & Qt::AlignLeft )
                r.setX(r.x() + indent);
            else if ( renderFlags & Qt::AlignRight )
                r.setWidth(r.width() - indent);
            else if ( renderFlags & Qt::AlignTop )
                r.setY(r.y() + indent);
            else if ( renderFlags & Qt::AlignBottom )
                r.setHeight(r.height() - indent);
        }
    }

    return r;
}

int QwtTextLabel::defaultIndent() const
{
    if ( frameWidth() <= 0 )
        return 0;

    QFont fnt;
    if ( d_data->text.testPaintAttribute(QwtText::PaintUsingTextFont) )
        fnt = d_data->text.font();
    else
        fnt = font();

    return QFontMetrics(fnt).width('x') / 2;
}