plasma-framework/widgets/label.cpp

/*
 *   Copyright 2008 Aaron Seigo <aseigo@kde.org>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as
 *   published by the Free Software Foundation; either version 2, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this program; if not, write to the
 *   Free Software Foundation, Inc.,
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include "label.h"

#include <QApplication>
#include <QLabel>
#include <QPainter>
#include <QDir>
#include <QStyleOptionGraphicsItem>
#include <QGraphicsSceneMouseEvent>
#include <QMenu>

#include <kmimetype.h>
#include <kglobalsettings.h>
#include <kcolorscheme.h>

#include "theme.h"
#include "svg.h"

namespace Plasma
{

class LabelPrivate
{
public:
    LabelPrivate(Label *label)
        : q(label),
          svg(0),
          customFont(false)
    {
    }

    ~LabelPrivate()
    {
        delete svg;
    }

    void setPixmap()
    {
        if (imagePath.isEmpty()) {
            delete svg;
            svg = 0;
            return;
        }

        KMimeType::Ptr mime = KMimeType::findByPath(absImagePath);
        QPixmap pm(q->size().toSize());

        if (mime->is("image/svg+xml") || mime->is("image/svg+xml-compressed")) {
            if (!svg || svg->imagePath() != absImagePath) {
                delete svg;
                svg = new Svg();
                svg->setImagePath(imagePath);
                QObject::connect(svg, SIGNAL(repaintNeeded()), q, SLOT(setPixmap()));
            }

            QPainter p(&pm);
            svg->paint(&p, pm.rect());
        } else {
            delete svg;
            svg = 0;
            pm = QPixmap(absImagePath);
        }

        static_cast<QLabel*>(q->widget())->setPixmap(pm);
    }

    void setPalette()
    {
        QLabel *native = q->nativeWidget();
        QColor color = Theme::defaultTheme()->color(Theme::TextColor);
        QPalette p = native->palette();
        p.setColor(QPalette::Normal, QPalette::WindowText, color);
        p.setColor(QPalette::Inactive, QPalette::WindowText, color);
        color.setAlphaF(0.6);
        p.setColor(QPalette::Disabled, QPalette::WindowText, color);

        p.setColor(QPalette::Normal, QPalette::Link, Theme::defaultTheme()->color(Theme::LinkColor));
        p.setColor(QPalette::Normal, QPalette::LinkVisited, Theme::defaultTheme()->color(Theme::VisitedLinkColor));
        native->setPalette(p);

        if (!customFont) {
            q->nativeWidget()->setFont(Plasma::Theme::defaultTheme()->font(Plasma::Theme::DefaultFont));
        }
    }

    Label *q;
    QString imagePath;
    QString absImagePath;
    Svg *svg;
    bool textSelectable;
    bool customFont;
};

Label::Label(QGraphicsWidget *parent)
    : QGraphicsProxyWidget(parent),
      d(new LabelPrivate(this))
{
    QLabel *native = new QLabel;
    native->setWindowFlags(native->windowFlags()|Qt::BypassGraphicsProxyWidget);
    d->textSelectable = false;
    connect(native, SIGNAL(linkActivated(QString)), this, SIGNAL(linkActivated(QString)));
    connect(native, SIGNAL(linkHovered(QString)), this, SIGNAL(linkHovered(QString)));

    connect(Theme::defaultTheme(), SIGNAL(themeChanged()), this, SLOT(setPalette()));
    connect(KGlobalSettings::self(), SIGNAL(kdisplayPaletteChanged()), this, SLOT(setPalette()));

    native->setAttribute(Qt::WA_NoSystemBackground);
    native->setWordWrap(true);
    setWidget(native);
    d->setPalette();
}

Label::~Label()
{
    delete d;
}

void Label::setText(const QString &text)
{
    static_cast<QLabel*>(widget())->setText(text);
    updateGeometry();
}

QString Label::text() const
{
    return static_cast<QLabel*>(widget())->text();
}

void Label::setImage(const QString &path)
{
    if (d->imagePath == path) {
        return;
    }

    delete d->svg;
    d->svg = 0;
    d->imagePath = path;

    bool absolutePath = !path.isEmpty() &&
                        #ifdef Q_WS_WIN
                            !QDir::isRelativePath(path)
                        #else
                            (path[0] == '/' || path.startsWith(QLatin1String(":/")))
                        #endif
        ;

    if (absolutePath) {
        d->absImagePath = path;
    } else {
        //TODO: package support
        d->absImagePath = Theme::defaultTheme()->imagePath(path);
    }

    d->setPixmap();
}

QString Label::image() const
{
    return d->imagePath;
}

void Label::setScaledContents(bool scaled)
{
    static_cast<QLabel*>(widget())->setScaledContents(scaled);
}

bool Label::hasScaledContents() const
{
    return static_cast<QLabel*>(widget())->hasScaledContents();
}

void Label::setTextSelectable(bool enable)
{
    if (enable) {
        nativeWidget()->setTextInteractionFlags(Qt::TextBrowserInteraction);
    } else {
        nativeWidget()->setTextInteractionFlags(Qt::LinksAccessibleByMouse);
    }

    d->textSelectable = enable;
}

bool Label::textSelectable() const
{
  return d->textSelectable;
}

void Label::setAlignment(Qt::Alignment alignment)
{
    nativeWidget()->setAlignment(alignment);
}

Qt::Alignment Label::alignment() const
{
    return nativeWidget()->alignment();
}

void Label::setWordWrap(bool wrap)
{
    nativeWidget()->setWordWrap(wrap);
}

bool Label::wordWrap() const
{
    return nativeWidget()->wordWrap();
}

void Label::setStyleSheet(const QString &stylesheet)
{
    widget()->setStyleSheet(stylesheet);
}

QString Label::styleSheet()
{
    return widget()->styleSheet();
}

QLabel *Label::nativeWidget() const
{
    return static_cast<QLabel*>(widget());
}

void Label::dataUpdated(const QString &sourceName, const Plasma::DataEngine::Data &data)
{
    Q_UNUSED(sourceName);

    QStringList texts;
    foreach (const QVariant &v, data) {
        if (v.canConvert(QVariant::String)) {
            texts << v.toString();
        }
    }

    setText(texts.join(" "));
}

void Label::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
{
    QContextMenuEvent contextMenuEvent(QContextMenuEvent::Reason(event->reason()),
                                       event->pos().toPoint(), event->screenPos(), event->modifiers());
    QApplication::sendEvent(nativeWidget(), &contextMenuEvent);
}

void Label::resizeEvent(QGraphicsSceneResizeEvent *event)
{
    d->setPixmap();
    QGraphicsProxyWidget::resizeEvent(event);
}

void Label::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    QGraphicsProxyWidget::mousePressEvent(event);
    //FIXME: when QTextControl accept()s mouse press events (as of Qt 4.6.2, it processes them
    //but never marks them as accepted) the following event->accept() can be removed
    if (d->textSelectable) {
        event->accept();
    }
}

void Label::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    if (d->textSelectable) {
        QGraphicsProxyWidget::mouseMoveEvent(event);
    }
}

void Label::paint(QPainter *painter,
                  const QStyleOptionGraphicsItem *option,
                  QWidget *widget)
{
    QGraphicsProxyWidget::paint(painter, option, widget);
    /*
        NOTE: if we don't get any coplaints about "unitialized random gibberish" as in the FIXME
        below, then we can just get rid of this entire block of code.it really depends on whether
        or not Qt has been fixed since this was written
    QLabel *native = nativeWidget();
    QFontMetrics fm = native->font();

    //FIXME: using QGraphicsProxyWidget::paint directly with opacity<1 produces uninitialized random gibberish
    if (qFuzzyCompare((qreal)1.0, opacity()) && (native->wordWrap() || native->text().isEmpty() || size().width() >= fm.width(native->text()))) {
        QGraphicsProxyWidget::paint(painter, option, widget);
    } else {
        const int gradientLength = 25;
        QPixmap buffer(contentsRect().size().toSize());
        buffer.fill(Qt::transparent);

        QPainter buffPainter(&buffer);

        QGraphicsProxyWidget::paint(&buffPainter, option, widget);

        QLinearGradient gr;

        buffPainter.setCompositionMode(QPainter::CompositionMode_DestinationIn);
        buffPainter.setPen(Qt::NoPen);

        if (option->direction == Qt::LeftToRight) {
            gr.setStart(size().width()-gradientLength, 0);
            gr.setFinalStop(size().width(), 0);
            gr.setColorAt(0, Qt::black);
            gr.setColorAt(1, Qt::transparent);
            buffPainter.setBrush(gr);

            buffPainter.drawRect(QRect(gr.start().toPoint(), QSize(gradientLength, size().height())));
        } else {
            gr.setStart(0, 0);
            gr.setFinalStop(gradientLength, 0);
            gr.setColorAt(0, Qt::transparent);
            gr.setColorAt(1, Qt::black);
            buffPainter.setBrush(gr);

            buffPainter.drawRect(QRect(0, 0, gradientLength, size().height()));
        }

        buffPainter.end();
        painter->drawPixmap(contentsRect(), buffer, buffer.rect());
    }
    */
}

void Label::changeEvent(QEvent *event)
{
    if (event->type() == QEvent::FontChange && font() != QApplication::font()) {
        d->customFont = true;
        nativeWidget()->setFont(font());
    }

    QGraphicsProxyWidget::changeEvent(event);
}

bool Label::event(QEvent *event)
{
    if (event->type() == QEvent::Show && font() != QApplication::font()) {
        d->customFont = true;
        nativeWidget()->setFont(font());
    }
    return QGraphicsProxyWidget::event(event);
}

QVariant Label::itemChange(GraphicsItemChange change, const QVariant & value)
{
    if (change == QGraphicsItem::ItemCursorHasChanged) {
        nativeWidget()->setCursor(cursor());
    }

    return QGraphicsWidget::itemChange(change, value);
}

QSizeF Label::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
{
    if (sizePolicy().verticalPolicy() == QSizePolicy::Fixed) {
        return QGraphicsProxyWidget::sizeHint(Qt::PreferredSize, constraint);
    } else {
        return QGraphicsProxyWidget::sizeHint(which, constraint);
    }
}

} // namespace Plasma

#include <label.moc>