qcommandlinkbutton.cpp

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#include "qcommandlinkbutton.h"
#include "qstylepainter.h"
#include "qstyleoption.h"
#include "qtextdocument.h"
#include "qtextlayout.h"
#include "qcolor.h"
#include "qfont.h"
#include <qmath.h>

#include "private/qpushbutton_p.h"

QT_BEGIN_NAMESPACE

class QCommandLinkButtonPrivate : public QPushButtonPrivate
{
    Q_DECLARE_PUBLIC(QCommandLinkButton)

public:
    QCommandLinkButtonPrivate()
        : QPushButtonPrivate(){}

    void init();
    qreal titleSize() const;
    bool usingVistaStyle() const;

    QFont titleFont() const;
    QFont descriptionFont() const;

    QRect titleRect() const;
    QRect descriptionRect() const;

    int textOffset() const;
    int descriptionOffset() const;
    int descriptionHeight(int width) const;
    QColor mergedColors(const QColor &a, const QColor &b, int value) const;

    int topMargin() const { return 10; }
    int leftMargin() const { return 7; }
    int rightMargin() const { return 4; }
    int bottomMargin() const { return 10; }

    QString description;
    QColor currentColor;
};

// Mix colors a and b with a ratio in the range [0-255]
QColor QCommandLinkButtonPrivate::mergedColors(const QColor &a, const QColor &b, int value = 50) const
{
    Q_ASSERT(value >= 0);
    Q_ASSERT(value <= 255);
    QColor tmp = a;
    tmp.setRed((tmp.red() * value) / 255 + (b.red() * (255 - value)) / 255);
    tmp.setGreen((tmp.green() * value) / 255 + (b.green() * (255 - value)) / 255);
    tmp.setBlue((tmp.blue() * value) / 255 + (b.blue() * (255 - value)) / 255);
    return tmp;
}

QFont QCommandLinkButtonPrivate::titleFont() const
{
    Q_Q(const QCommandLinkButton);
    QFont font = q->font();
    if (usingVistaStyle()) {
        font.setPointSizeF(12.0);
    } else {
        font.setBold(true);
        font.setPointSizeF(9.0);
    }

    // Note the font will be resolved against
    // QPainters font, so we need to restore the mask
    int resolve_mask = font.resolve_mask;
    QFont modifiedFont = q->font().resolve(font);
    modifiedFont.detach();
    modifiedFont.resolve_mask = resolve_mask;
    return modifiedFont;
}

QFont QCommandLinkButtonPrivate::descriptionFont() const
{
    Q_Q(const QCommandLinkButton);
    QFont font = q->font();
    font.setPointSizeF(9.0);

    // Note the font will be resolved against
    // QPainters font, so we need to restore the mask
    int resolve_mask = font.resolve_mask;
    QFont modifiedFont = q->font().resolve(font);
    modifiedFont.detach();
    modifiedFont.resolve_mask = resolve_mask;
    return modifiedFont;
}

QRect QCommandLinkButtonPrivate::titleRect() const
{
    Q_Q(const QCommandLinkButton);
    QRect r = q->rect().adjusted(textOffset(), topMargin(), -rightMargin(), 0);
    if (description.isEmpty())
    {
        QFontMetrics fm(titleFont());
        r.setTop(r.top() + qMax(0, (q->icon().actualSize(q->iconSize()).height()
                 - fm.height()) / 2));
    }

    return r;
}

QRect QCommandLinkButtonPrivate::descriptionRect() const
{
    Q_Q(const QCommandLinkButton);
    return q->rect().adjusted(textOffset(), descriptionOffset(),
                              -rightMargin(), -bottomMargin());
}

int QCommandLinkButtonPrivate::textOffset() const
{
    Q_Q(const QCommandLinkButton);
    return q->icon().actualSize(q->iconSize()).width() + leftMargin() + 6;
}

int QCommandLinkButtonPrivate::descriptionOffset() const
{
    QFontMetrics fm(titleFont());
    return topMargin() + fm.height();
}

bool QCommandLinkButtonPrivate::usingVistaStyle() const
{
    Q_Q(const QCommandLinkButton);
    //### This is a hack to detect if we are indeed running Vista style themed and not in classic
    // When we add api to query for this, we should change this implementation to use it.
    return q->style()->inherits("QWindowsVistaStyle")
        && !q->style()->pixelMetric(QStyle::PM_ButtonShiftHorizontal);
}

void QCommandLinkButtonPrivate::init()
{
    Q_Q(QCommandLinkButton);
    QPushButtonPrivate::init();
    q->setAttribute(Qt::WA_Hover);

    QSizePolicy policy(QSizePolicy::Preferred, QSizePolicy::Preferred, QSizePolicy::PushButton);
    policy.setHeightForWidth(true);
    q->setSizePolicy(policy);

    q->setIconSize(QSize(20, 20));
    QStyleOptionButton opt;
    q->initStyleOption(&opt);
    q->setIcon(q->style()->standardIcon(QStyle::SP_CommandLink, &opt));
}

// Calculates the height of the description text based on widget width
int QCommandLinkButtonPrivate::descriptionHeight(int widgetWidth) const
{
    // Calc width of actual paragraph
    int lineWidth = widgetWidth - textOffset() - rightMargin();

    qreal descriptionheight = 0;
    if (!description.isEmpty()) {
        QTextLayout layout(description);
        layout.setFont(descriptionFont());
        layout.beginLayout();
        while (true) {
            QTextLine line = layout.createLine();
            if (!line.isValid())
                break;
            line.setLineWidth(lineWidth);
            line.setPosition(QPointF(0, descriptionheight));
            descriptionheight += line.height();
        }
        layout.endLayout();
    }
    return qCeil(descriptionheight);
}

QSize QCommandLinkButton::minimumSizeHint() const
{
    Q_D(const QCommandLinkButton);
    QSize size = sizeHint();
    int minimumHeight = qMax(d->descriptionOffset() + d->bottomMargin(),
                             icon().actualSize(iconSize()).height() + d->topMargin());
    size.setHeight(minimumHeight);
    return size;
}

QCommandLinkButton::QCommandLinkButton(QWidget *parent)
: QPushButton(*new QCommandLinkButtonPrivate, parent)
{
    Q_D(QCommandLinkButton);
    d->init();
}

QCommandLinkButton::QCommandLinkButton(const QString &text, QWidget *parent)
    : QPushButton(*new QCommandLinkButtonPrivate, parent)
{
    Q_D(QCommandLinkButton);
    setText(text);
    d->init();
}

QCommandLinkButton::QCommandLinkButton(const QString &text, const QString &description, QWidget *parent)
    : QPushButton(*new QCommandLinkButtonPrivate, parent)
{
    Q_D(QCommandLinkButton);
    setText(text);
    setDescription(description);
    d->init();
}

bool QCommandLinkButton::event(QEvent *e)
{
    return QPushButton::event(e);
}

QSize QCommandLinkButton::sizeHint() const
{
//  Standard size hints from UI specs
//  Without note: 135, 41
//  With note: 135, 60
    Q_D(const QCommandLinkButton);

    QSize size = QPushButton::sizeHint();
    QFontMetrics fm(d->titleFont());
    int textWidth = qMax(fm.width(text()), 135);
    int buttonWidth = textWidth + d->textOffset() + d->rightMargin();
    int heightWithoutDescription = d->descriptionOffset() + d->bottomMargin();

    size.setWidth(qMax(size.width(), buttonWidth));
    size.setHeight(qMax(d->description.isEmpty() ? 41 : 60,
                        heightWithoutDescription + d->descriptionHeight(buttonWidth)));
    return size;
}

int QCommandLinkButton::heightForWidth(int width) const
{
    Q_D(const QCommandLinkButton);
    int heightWithoutDescription = d->descriptionOffset() + d->bottomMargin();
    // find the width available for the description area
    return qMax(heightWithoutDescription + d->descriptionHeight(width),
                icon().actualSize(iconSize()).height() + d->topMargin() +
                d->bottomMargin());
}

void QCommandLinkButton::paintEvent(QPaintEvent *)
{
    Q_D(QCommandLinkButton);
    QStylePainter p(this);
    p.save();

    QStyleOptionButton option;
    initStyleOption(&option);

    //Enable command link appearance on Vista
    option.features |= QStyleOptionButton::CommandLinkButton;
    option.text = QString();
    option.icon = QIcon(); //we draw this ourselves
    QSize pixmapSize = icon().actualSize(iconSize());

    int vOffset = isDown() ? style()->pixelMetric(QStyle::PM_ButtonShiftVertical) : 0;
    int hOffset = isDown() ? style()->pixelMetric(QStyle::PM_ButtonShiftHorizontal) : 0;

    //Draw icon
    p.drawControl(QStyle::CE_PushButton, option);
    if (!icon().isNull())
        p.drawPixmap(d->leftMargin() + hOffset, d->topMargin() + vOffset,
        icon().pixmap(pixmapSize, isEnabled() ? QIcon::Normal : QIcon::Disabled,
                                  isChecked() ? QIcon::On : QIcon::Off));

    //Draw title
    QColor textColor = palette().buttonText().color();
    if (isEnabled() && d->usingVistaStyle()) {
        textColor = QColor(21, 28, 85);
        if (underMouse() && !isDown())
            textColor = QColor(7, 64, 229);
        //A simple text color transition
        d->currentColor = d->mergedColors(textColor, d->currentColor, 60);
        option.palette.setColor(QPalette::ButtonText, d->currentColor);
    }

    int textflags = Qt::TextShowMnemonic;
    if (!style()->styleHint(QStyle::SH_UnderlineShortcut, &option, this))
        textflags |= Qt::TextHideMnemonic;

    p.setFont(d->titleFont());
    p.drawItemText(d->titleRect().translated(hOffset, vOffset),
                    textflags, option.palette, isEnabled(), text(), QPalette::ButtonText);

    //Draw description
    textflags |= Qt::TextWordWrap | Qt::ElideRight;
    p.setFont(d->descriptionFont());
    p.drawItemText(d->descriptionRect().translated(hOffset, vOffset), textflags,
                    option.palette, isEnabled(), description(), QPalette::ButtonText);
    p.restore();
}

void QCommandLinkButton::setDescription(const QString &description)
{
    Q_D(QCommandLinkButton);
    d->description = description;
    updateGeometry();
    update();
}

QString QCommandLinkButton::description() const
{
    Q_D(const QCommandLinkButton);
    return d->description;
}

QT_END_NAMESPACE