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****************************************************************************/

#include "spacer_widget_p.h"

#include "layoutinfo_p.h"

#include <QtDesigner/abstractformwindow.h>

#include <QtDesigner/QDesignerFormWindowInterface>

#include <QtDesigner/QDesignerFormEditorInterface>

#include <QtDesigner/QDesignerPropertySheetExtension>

#include <QtDesigner/QExtensionManager>

#include <QtGui/QLayout>

#include <QtGui/QPainter>

#include <QtGui/qevent.h>

#include <QtCore/qdebug.h>

QT_BEGIN_NAMESPACE

// The Spacer widget is Designer representation of  QLayoutItem.

// It uses QLayoutItem's sizeHint property as QWidget

// sizeHint and the QLayoutItem's sizeType property as QWidget size policy.

// If it is not within a layout, it adds a margin (m_SizeOffset) around it

// to avoid being shrunk to an invisible state when the sizeHint is reset to 0,0

// and enables sizeHandle-resizing. In a layout, however, this m_SizeOffset

// should not be applied for  pixel-exact design.

Spacer::Spacer(QWidget *parent) :

    QWidget(parent),

    m_SizeOffset(3, 3), // A small offset to ensure the spacer is still visible when reset to size 0,0

    m_orientation(Qt::Vertical),

    m_interactive(true),

    m_layoutState(UnknownLayoutState),

    m_sizeHint(0, 0)

{

    setAttribute(Qt::WA_MouseNoMask);

    m_formWindow = QDesignerFormWindowInterface::findFormWindow(this);

    setSizeType(QSizePolicy::Expanding);

}

bool Spacer::event(QEvent *e)

{

    switch (e->type()) {

    case QEvent::ToolTip:

        updateToolTip(); // Tooltip includes size, so, refresh on demand

        break;

    case QEvent::ParentChange: // Cache information about 'being in layout' which is expensive to calculate.

        m_layoutState = UnknownLayoutState;

        break;

    default:

        break;

    }

    return QWidget::event(e);

}

bool Spacer::isInLayout() const

{

    if (m_layoutState == UnknownLayoutState) {

        m_layoutState = OutsideLayout;

        if (m_formWindow)

            if (const QWidget *parent = parentWidget())

                if (qdesigner_internal::LayoutInfo::managedLayoutType(m_formWindow->core(), parent) != qdesigner_internal::LayoutInfo::NoLayout)

                    m_layoutState = InLayout;

    }

    return m_layoutState == InLayout;

}

void Spacer::paintEvent(QPaintEvent *)

{

    // Only draw spacers when we're editting widgets

    if (m_formWindow != 0 && m_formWindow->currentTool() != 0)

        return;

    QPainter p(this);

    p.setPen(Qt::blue);

    const int w = width();

    const int h = height();

    if (w * h == 0)

        return;

    if (w <= m_SizeOffset.width() || h <= m_SizeOffset.height()) {

        const int lw = w - 1;

        const int lh = h - 1;

        switch (m_orientation) {

        case Qt::Horizontal:

            p.drawLine(0,  0, 0,  lh);

            p.drawLine(lw, 0, lw, lh);

            break;

        case Qt::Vertical:

            p.drawLine(0, 0,  lw, 0);

            p.drawLine(0, lh, lw, lh);

            break;

        }

        return;

    }

    if (m_orientation == Qt::Horizontal) {

        const int dist = 3;

        const int amplitude = qMin(3, h / 3);

        const int base = h / 2;

        int i = 0;

        p.setPen(Qt::white);

        for (i = 0; i < w / 3 +2; ++i)

            p.drawLine(i * dist, base - amplitude, i * dist + dist / 2, base + amplitude);

        p.setPen(Qt::blue);

        for (i = 0; i < w / 3 +2; ++i)

            p.drawLine(i * dist + dist / 2, base + amplitude, i * dist + dist, base - amplitude);

        const int y = h/2;

        p.drawLine(0, y-10, 0, y+10);

        p.drawLine(w - 1, y-10, w - 1, y+10);

    } else {

        const int dist = 3;

        const int amplitude = qMin(3, w / 3);

        const int base = w / 2;

        int i = 0;

        p.setPen(Qt::white);

        for (i = 0; i < h / 3 +2; ++i)

            p.drawLine(base - amplitude, i * dist, base + amplitude,i * dist + dist / 2);

        p.setPen(Qt::blue);

        for (i = 0; i < h / 3 +2; ++i)

            p.drawLine(base + amplitude, i * dist + dist / 2, base - amplitude, i * dist + dist);

        const int x = w/2;

        p.drawLine(x-10, 0, x+10, 0);

        p.drawLine(x-10, h - 1, x+10, h - 1);

    }

}

void Spacer::resizeEvent(QResizeEvent* e)

{

    QWidget::resizeEvent(e);

    // When resized by widget handle dragging after a reset (QSize(0, 0)):

    // Mark the property as changed (geometry and sizeHint are in sync except for 'changed').

    if (m_formWindow) {

        const QSize oldSize = e->oldSize();

        if (oldSize.isNull() || oldSize.width() <= m_SizeOffset.width() || oldSize.height() <= m_SizeOffset.height())

            if (QDesignerPropertySheetExtension *sheet = qt_extension<QDesignerPropertySheetExtension*>(m_formWindow->core()->extensionManager(), this))

                sheet->setChanged(sheet->indexOf(QLatin1String("sizeHint")), true);

    }

    updateMask();

    if (!m_interactive)

        return;

    if (!isInLayout()) { // Allow size-handle resize only if not in layout

        const QSize currentSize = size();

        if (currentSize.width() >= m_SizeOffset.width() && currentSize.height() >= m_SizeOffset.height())

            m_sizeHint = currentSize - m_SizeOffset;

    }

}

void Spacer::updateMask()

{

    QRegion r(rect());

    const int w = width();

    const int h = height();

    if (w > 1 && h > 1) {

        if (m_orientation == Qt::Horizontal) {

            const int amplitude = qMin(3, h / 3);

            const int base = h / 2;

            r = r.subtract(QRect(1, 0, w - 2, base - amplitude));

            r = r.subtract(QRect(1, base + amplitude, w - 2, h - base - amplitude));

        } else {

            const int amplitude = qMin(3, w / 3);

            const int base = w / 2;

            r = r.subtract(QRect(0, 1, base - amplitude, h - 2));

            r = r.subtract(QRect(base + amplitude, 1, w - base - amplitude, h - 2));

        }

    }

    setMask(r);

}

void Spacer::setSizeType(QSizePolicy::Policy t)

{

    const QSizePolicy sizeP = m_orientation == Qt::Vertical ? QSizePolicy(QSizePolicy::Minimum, t) : QSizePolicy(t, QSizePolicy::Minimum);

    setSizePolicy(sizeP);

}

QSizePolicy::Policy Spacer::sizeType() const

{

    return m_orientation == Qt::Vertical ? sizePolicy().verticalPolicy() : sizePolicy().horizontalPolicy();

}

Qt::Alignment Spacer::alignment() const

{

    // For grid layouts

    return m_orientation == Qt::Vertical ?  Qt::AlignHCenter : Qt::AlignVCenter;

}

QSize Spacer::sizeHint() const

{

    return isInLayout() ? m_sizeHint : m_sizeHint + m_SizeOffset;

}

QSize Spacer::sizeHintProperty() const

{

    return m_sizeHint;

}

void Spacer::setSizeHintProperty(const QSize &s)

{

    m_sizeHint = s;

    if (!isInLayout()) // Visible resize only if not in layout

        resize(s + m_SizeOffset);

    updateGeometry();

}

Qt::Orientation Spacer::orientation() const

{

    return m_orientation;

}

void Spacer::setOrientation(Qt::Orientation o)

{

    if (m_orientation == o)

        return;

    const QSizePolicy::Policy st = sizeType(); // flip size type

    m_orientation = o;

    setSizeType(st);

    if (m_interactive) {

        m_sizeHint = QSize(m_sizeHint.height(), m_sizeHint.width());

        if (!isInLayout())

            resize(m_sizeHint + m_SizeOffset);

    }

    updateMask();

    update();

    updateGeometry();

}

void Spacer::updateToolTip()

{

    const QString format = m_orientation == Qt::Horizontal ? tr("Horizontal Spacer '%1', %2 x %3") : tr("Vertical Spacer '%1', %2 x %3");

    QString msg = format.arg(objectName()).arg(m_sizeHint.width()).arg(m_sizeHint.height());

    setToolTip(msg);

}

QT_END_NAMESPACE