path: root/src/declarative/graphicsitems/qdeclarativerectangle.cpp

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#include "private/qdeclarativerectangle_p.h"
#include "private/qdeclarativerectangle_p_p.h"

#include <QPainter>
#include <QStringBuilder>
#include <QtCore/qmath.h>

QT_BEGIN_NAMESPACE

/*!
    \internal
    \class QDeclarativePen
    \brief The QDeclarativePen class provides a pen used for drawing rectangle borders on a QDeclarativeView.

    By default, the pen is invalid and nothing is drawn. You must either set a color (then the default
    width is 1) or a width (then the default color is black).

    A width of 1 indicates is a single-pixel line on the border of the item being painted.

    Example:
    \qml
    Rectangle { border.width: 2; border.color: "red" ... }
    \endqml
*/

void QDeclarativePen::setColor(const QColor &c)
{
    _color = c;
    _valid = _color.alpha() ? true : false;
    emit penChanged();
}

void QDeclarativePen::setWidth(int w)
{
    if (_width == w && _valid)
        return;

    _width = w;
    _valid = (_width < 1) ? false : true;
    emit penChanged();
}


/*!
    \qmlclass GradientStop QDeclarativeGradientStop
    \ingroup qml-basic-visual-elements
  \since 4.7
    \brief The GradientStop item defines the color at a position in a Gradient

    \sa Gradient
*/

/*!
    \qmlproperty real GradientStop::position
    \qmlproperty color GradientStop::color

    Sets a \e color at a \e position in a gradient.
*/

void QDeclarativeGradientStop::updateGradient()
{
    if (QDeclarativeGradient *grad = qobject_cast<QDeclarativeGradient*>(parent()))
        grad->doUpdate();
}

/*!
    \qmlclass Gradient QDeclarativeGradient
    \ingroup qml-basic-visual-elements
  \since 4.7
    \brief The Gradient item defines a gradient fill.

    A gradient is defined by two or more colors, which will be blended seemlessly.  The
    colors are specified at their position in the range 0.0 - 1.0 via
    the GradientStop item.  For example, the following code paints a
    rectangle with a gradient starting with red, blending to yellow at 1/3 of the
    size of the rectangle, and ending with Green:

    \snippet doc/src/snippets/declarative/gradient.qml code

    Note that this item is not a visual representation of a gradient. To display a
    gradient use a visual item (like rectangle) which supports having a gradient set
    on it for display.

    \sa GradientStop
*/

/*!
    \qmlproperty list<GradientStop> Gradient::stops
    This property holds the gradient stops describing the gradient.
*/

const QGradient *QDeclarativeGradient::gradient() const
{
    if (!m_gradient && !m_stops.isEmpty()) {
        m_gradient = new QLinearGradient(0,0,0,1.0);
        for (int i = 0; i < m_stops.count(); ++i) {
            const QDeclarativeGradientStop *stop = m_stops.at(i);
            m_gradient->setCoordinateMode(QGradient::ObjectBoundingMode);
            m_gradient->setColorAt(stop->position(), stop->color());
        }
    }

    return m_gradient;
}

void QDeclarativeGradient::doUpdate()
{
    delete m_gradient;
    m_gradient = 0;
    emit updated();
}


/*!
    \qmlclass Rectangle QDeclarativeRectangle
    \ingroup qml-basic-visual-elements
  \since 4.7
    \brief The Rectangle item allows you to add rectangles to a scene.
    \inherits Item

    A Rectangle is painted using a solid fill (color) and an optional border.
    You can also create rounded rectangles using the \l radius property.

    \qml
    import Qt 4.7

    Rectangle {
        width: 100
        height: 100
        color: "red"
        border.color: "black"
        border.width: 5
        radius: 10
    }
    \endqml

    \image declarative-rect.png
*/

int QDeclarativeRectanglePrivate::doUpdateSlotIdx = -1;

QDeclarativeRectangle::QDeclarativeRectangle(QDeclarativeItem *parent)
  : QDeclarativeItem(*(new QDeclarativeRectanglePrivate), parent)
{
}

void QDeclarativeRectangle::doUpdate()
{
    Q_D(QDeclarativeRectangle);
    d->rectImage = QPixmap();
    const int pw = d->pen && d->pen->isValid() ? d->pen->width() : 0;
    d->setPaintMargin((pw+1)/2);
    update();
}

/*!
    \qmlproperty int Rectangle::border.width
    \qmlproperty color Rectangle::border.color

    The width and color used to draw the border of the rectangle.

    A width of 1 creates a thin line. For no line, use a width of 0 or a transparent color.

    If \c border.width is an odd number, the rectangle is painted at a half-pixel offset to retain
    border smoothness. Also, the border is rendered evenly on either side of the 
    rectangle's boundaries, and the spare pixel is rendered to the right and below the
    rectangle (as documented for QRect rendering). This can cause unintended effects if 
    \c border.width is 1 and the rectangle is \l{Item::clip}{clipped} by a parent item:
   
    \table
    \row
    \o \snippet doc/src/snippets/declarative/rect-border-width.qml 0
    \o \image rect-border-width.png
    \endtable

    Here, the innermost rectangle's border is clipped on the bottom and right edges by its
    parent. To avoid this, the border width can be set to two instead of one.
*/
QDeclarativePen *QDeclarativeRectangle::border()
{
    Q_D(QDeclarativeRectangle);
    return d->getPen();
}

/*!
    \qmlproperty Gradient Rectangle::gradient

    The gradient to use to fill the rectangle.

    This property allows for the construction of simple vertical gradients.
    Other gradients may by formed by adding rotation to the rectangle.

    \table
    \row
    \o \image declarative-rect_gradient.png
    \o
    \qml
    Rectangle {
        y: 0; width: 80; height: 80
        color: "lightsteelblue"
    }

    Rectangle {
        y: 100; width: 80; height: 80
        gradient: Gradient {
            GradientStop { position: 0.0; color: "lightsteelblue" }
            GradientStop { position: 1.0; color: "blue" }
        }
    }

    Rectangle {
        y: 200; width: 80; height: 80
        rotation: 90
        gradient: Gradient {
            GradientStop { position: 0.0; color: "lightsteelblue" }
            GradientStop { position: 1.0; color: "blue" }
        }
    }
    \endqml
    \endtable

    If both a gradient and a color are specified, the gradient will be used.

    \sa Gradient, color
*/
QDeclarativeGradient *QDeclarativeRectangle::gradient() const
{
    Q_D(const QDeclarativeRectangle);
    return d->gradient;
}

void QDeclarativeRectangle::setGradient(QDeclarativeGradient *gradient)
{
    Q_D(QDeclarativeRectangle);
    if (d->gradient == gradient)
        return;
    static int updatedSignalIdx = -1;
    if (updatedSignalIdx < 0)
        updatedSignalIdx = QDeclarativeGradient::staticMetaObject.indexOfSignal("updated()");
    if (d->doUpdateSlotIdx < 0)
        d->doUpdateSlotIdx = QDeclarativeRectangle::staticMetaObject.indexOfSlot("doUpdate()");
    if (d->gradient)
        QMetaObject::disconnect(d->gradient, updatedSignalIdx, this, d->doUpdateSlotIdx);
    d->gradient = gradient;
    if (d->gradient)
        QMetaObject::connect(d->gradient, updatedSignalIdx, this, d->doUpdateSlotIdx);
    update();
}


/*!
    \qmlproperty real Rectangle::radius
    This property holds the corner radius used to draw a rounded rectangle.

    If radius is non-zero, the rectangle will be painted as a rounded rectangle, otherwise it will be
    painted as a normal rectangle. The same radius is used by all 4 corners; there is currently
    no way to specify different radii for different corners.
*/
qreal QDeclarativeRectangle::radius() const
{
    Q_D(const QDeclarativeRectangle);
    return d->radius;
}

void QDeclarativeRectangle::setRadius(qreal radius)
{
    Q_D(QDeclarativeRectangle);
    if (d->radius == radius)
        return;

    d->radius = radius;
    d->rectImage = QPixmap();
    update();
    emit radiusChanged();
}

/*!
    \qmlproperty color Rectangle::color
    This property holds the color used to fill the rectangle.

    \qml
    // green rectangle using hexidecimal notation
    Rectangle { color: "#00FF00" }

    // steelblue rectangle using SVG color name
    Rectangle { color: "steelblue" }
    \endqml

    The default color is white.

    If both a gradient and a color are specified, the gradient will be used.
*/
QColor QDeclarativeRectangle::color() const
{
    Q_D(const QDeclarativeRectangle);
    return d->color;
}

void QDeclarativeRectangle::setColor(const QColor &c)
{
    Q_D(QDeclarativeRectangle);
    if (d->color == c)
        return;

    d->color = c;
    d->rectImage = QPixmap();
    update();
    emit colorChanged();
}

void QDeclarativeRectangle::generateRoundedRect()
{
    Q_D(QDeclarativeRectangle);
    if (d->rectImage.isNull()) {
        const int pw = d->pen && d->pen->isValid() ? d->pen->width() : 0;
        const int radius = qCeil(d->radius);    //ensure odd numbered width/height so we get 1-pixel center

        QString key = QLatin1String("q_") % QString::number(pw) % d->color.name() % QString::number(d->color.alpha(), 16) % QLatin1Char('_') % QString::number(radius);
        if (d->pen && d->pen->isValid())
            key += d->pen->color().name() % QString::number(d->pen->color().alpha(), 16);

        if (!QPixmapCache::find(key, &d->rectImage)) {
            d->rectImage = QPixmap(radius*2 + 3 + pw*2, radius*2 + 3 + pw*2);
            d->rectImage.fill(Qt::transparent);
            QPainter p(&(d->rectImage));
            p.setRenderHint(QPainter::Antialiasing);
            if (d->pen && d->pen->isValid()) {
                QPen pn(QColor(d->pen->color()), d->pen->width());
                p.setPen(pn);
            } else {
                p.setPen(Qt::NoPen);
            }
            p.setBrush(d->color);
            if (pw%2)
                p.drawRoundedRect(QRectF(qreal(pw)/2+1, qreal(pw)/2+1, d->rectImage.width()-(pw+1), d->rectImage.height()-(pw+1)), d->radius, d->radius);
            else
                p.drawRoundedRect(QRectF(qreal(pw)/2, qreal(pw)/2, d->rectImage.width()-pw, d->rectImage.height()-pw), d->radius, d->radius);
            QPixmapCache::insert(key, d->rectImage);
        }
    }
}

void QDeclarativeRectangle::generateBorderedRect()
{
    Q_D(QDeclarativeRectangle);
    if (d->rectImage.isNull()) {
        const int pw = d->pen && d->pen->isValid() ? d->pen->width() : 0;

        QString key = QLatin1String("q_") % QString::number(pw) % d->color.name() % QString::number(d->color.alpha(), 16);
        if (d->pen && d->pen->isValid())
            key += d->pen->color().name() % QString::number(d->pen->color().alpha(), 16);

        if (!QPixmapCache::find(key, &d->rectImage)) {
            // Adding 5 here makes qDrawBorderPixmap() paint correctly with smooth: true
            // See QTBUG-7999 and QTBUG-10765 for more details.
            d->rectImage = QPixmap(pw*2 + 5, pw*2 + 5);
            d->rectImage.fill(Qt::transparent);
            QPainter p(&(d->rectImage));
            p.setRenderHint(QPainter::Antialiasing);
            if (d->pen && d->pen->isValid()) {
                QPen pn(QColor(d->pen->color()), d->pen->width());
                pn.setJoinStyle(Qt::MiterJoin);
                p.setPen(pn);
            } else {
                p.setPen(Qt::NoPen);
            }
            p.setBrush(d->color);
            if (pw%2)
                p.drawRect(QRectF(qreal(pw)/2+1, qreal(pw)/2+1, d->rectImage.width()-(pw+1), d->rectImage.height()-(pw+1)));
            else
                p.drawRect(QRectF(qreal(pw)/2, qreal(pw)/2, d->rectImage.width()-pw, d->rectImage.height()-pw));
            QPixmapCache::insert(key, d->rectImage);
        }
    }
}

void QDeclarativeRectangle::paint(QPainter *p, const QStyleOptionGraphicsItem *, QWidget *)
{
    Q_D(QDeclarativeRectangle);
    if (d->radius > 0 || (d->pen && d->pen->isValid())
        || (d->gradient && d->gradient->gradient()) ) {
        drawRect(*p);
    }
    else {
        bool oldAA = p->testRenderHint(QPainter::Antialiasing);
        if (d->smooth)
            p->setRenderHints(QPainter::Antialiasing, true);
        p->fillRect(QRectF(0, 0, width(), height()), d->color);
        if (d->smooth)
            p->setRenderHint(QPainter::Antialiasing, oldAA);
    }
}

void QDeclarativeRectangle::drawRect(QPainter &p)
{
    Q_D(QDeclarativeRectangle);
    if ((d->gradient && d->gradient->gradient())
        || d->radius > width()/2 || d->radius > height()/2) {
        // XXX This path is still slower than the image path
        // Image path won't work for gradients or invalid radius though
        bool oldAA = p.testRenderHint(QPainter::Antialiasing);
        if (d->smooth)
            p.setRenderHint(QPainter::Antialiasing);
        if (d->pen && d->pen->isValid()) {
            QPen pn(QColor(d->pen->color()), d->pen->width());
            pn.setJoinStyle(Qt::MiterJoin);
            p.setPen(pn);
        } else {
            p.setPen(Qt::NoPen);
        }
        if (d->gradient && d->gradient->gradient())
            p.setBrush(*d->gradient->gradient());
        else
            p.setBrush(d->color);
        const int pw = d->pen && d->pen->isValid() ? d->pen->width() : 0;
        QRectF rect;
        if (pw%2)
            rect = QRectF(0.5, 0.5, width()-1, height()-1);
        else
            rect = QRectF(0, 0, width(), height());
        qreal radius = d->radius;
        if (radius > width()/2 || radius > height()/2)
            radius = qMin(width()/2, height()/2);
        if (radius > 0.)
            p.drawRoundedRect(rect, radius, radius);
        else
            p.drawRect(rect);
        if (d->smooth)
            p.setRenderHint(QPainter::Antialiasing, oldAA);
    } else {
        bool oldAA = p.testRenderHint(QPainter::Antialiasing);
        bool oldSmooth = p.testRenderHint(QPainter::SmoothPixmapTransform);
        if (d->smooth)
            p.setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform, d->smooth);

        const int pw = d->pen && d->pen->isValid() ? (d->pen->width()+1)/2*2 : 0;

        if (d->radius > 0)
            generateRoundedRect();
        else
            generateBorderedRect();

        int xOffset = (d->rectImage.width()-1)/2;
        int yOffset = (d->rectImage.height()-1)/2;
        Q_ASSERT(d->rectImage.width() == 2*xOffset + 1);
        Q_ASSERT(d->rectImage.height() == 2*yOffset + 1);

        QMargins margins(xOffset, yOffset, xOffset, yOffset);
        QTileRules rules(Qt::StretchTile, Qt::StretchTile);
        //NOTE: even though our item may have qreal-based width and height, qDrawBorderPixmap only supports QRects
        qDrawBorderPixmap(&p, QRect(-pw/2, -pw/2, width()+pw, height()+pw), margins, d->rectImage, d->rectImage.rect(), margins, rules);

        if (d->smooth) {
            p.setRenderHint(QPainter::Antialiasing, oldAA);
            p.setRenderHint(QPainter::SmoothPixmapTransform, oldSmooth);
        }
    }
}

/*!
    \qmlproperty bool Rectangle::smooth

    Set this property if you want the item to be smoothly scaled or
    transformed.  Smooth filtering gives better visual quality, but is slower.  If
    the item is displayed at its natural size, this property has no visual or
    performance effect.

    \note Generally scaling artifacts are only visible if the item is stationary on
    the screen.  A common pattern when animating an item is to disable smooth
    filtering at the beginning of the animation and reenable it at the conclusion.

    \image rect-smooth.png
    On this image, smooth is turned off on the top half and on on the bottom half.
*/

QRectF QDeclarativeRectangle::boundingRect() const
{
    Q_D(const QDeclarativeRectangle);
    return QRectF(-d->paintmargin, -d->paintmargin, d->width()+d->paintmargin*2, d->height()+d->paintmargin*2);
}

QT_END_NAMESPACE