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**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
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** This file is part of Qt Creator.
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** use the contact form at http://qt.digia.com/contact-us.
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** GNU Lesser General Public License Usage
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** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
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****************************************************************************/

#include "detailsbutton.h"

#include <utils/hostosinfo.h>

#include <QGraphicsOpacityEffect>
#include <QPropertyAnimation>
#include <QPaintEvent>
#include <QPainter>
#include <QStyleOption>

#if QT_VERSION >= 0x050100
#include <QGuiApplication>
#endif

using namespace Utils;

FadingWidget::FadingWidget(QWidget *parent) :
    FadingPanel(parent),
    m_opacityEffect(new QGraphicsOpacityEffect)
{
    m_opacityEffect->setOpacity(0);
    setGraphicsEffect(m_opacityEffect);

    // Workaround for issue with QGraphicsEffect. GraphicsEffect
    // currently clears with Window color. Remove if flickering
    // no longer occurs on fade-in
    QPalette pal;
    pal.setBrush(QPalette::All, QPalette::Window, Qt::transparent);
    setPalette(pal);
}

void FadingWidget::setOpacity(qreal value)
{
    m_opacityEffect->setOpacity(value);
}

void FadingWidget::fadeTo(qreal value)
{
    QPropertyAnimation *animation = new QPropertyAnimation(m_opacityEffect, "opacity");
    animation->setDuration(200);
    animation->setEndValue(value);
    animation->start(QAbstractAnimation::DeleteWhenStopped);
}

qreal FadingWidget::opacity()
{
    return m_opacityEffect->opacity();
}

DetailsButton::DetailsButton(QWidget *parent) : QAbstractButton(parent), m_fader(0)
{
    setCheckable(true);
    setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Minimum);
    setText(tr("Details"));
}

QSize DetailsButton::sizeHint() const
{
    // TODO: Adjust this when icons become available!
    const int w = fontMetrics().width(text()) + 32;
    if (HostOsInfo::isMacHost())
        return QSize(w, 34);
    return QSize(w, 22);
}

bool DetailsButton::event(QEvent *e)
{
    switch (e->type()) {
    case QEvent::Enter:
        {
            QPropertyAnimation *animation = new QPropertyAnimation(this, "fader");
            animation->setDuration(200);
            animation->setEndValue(1.0);
            animation->start(QAbstractAnimation::DeleteWhenStopped);
        }
        break;
    case QEvent::Leave:
        {
            QPropertyAnimation *animation = new QPropertyAnimation(this, "fader");
            animation->setDuration(200);
            animation->setEndValue(0.0);
            animation->start(QAbstractAnimation::DeleteWhenStopped);
        }
        break;
    default:
        return QAbstractButton::event(e);
    }
    return false;
}

void DetailsButton::paintEvent(QPaintEvent *e)
{
    QWidget::paintEvent(e);

    QPainter p(this);

    // draw hover animation
    if (!HostOsInfo::isMacHost() && !isDown() && m_fader > 0)
        p.fillRect(rect().adjusted(1, 1, -2, -2), QColor(255, 255, 255, int(m_fader*180)));

    qreal checkedPixmapRatio = 1.0;
    qreal uncheckedPixmapRatio = 1.0;
#if QT_VERSION >= 0x050100
    checkedPixmapRatio = m_checkedPixmap.devicePixelRatio();
    uncheckedPixmapRatio = m_uncheckedPixmap.devicePixelRatio();
#endif

    if (isChecked()) {
        if (m_checkedPixmap.isNull() || m_checkedPixmap.size() / checkedPixmapRatio != contentsRect().size())
            m_checkedPixmap = cacheRendering(contentsRect().size(), true);
        p.drawPixmap(contentsRect(), m_checkedPixmap);
    } else {
        if (m_uncheckedPixmap.isNull() || m_uncheckedPixmap.size() / uncheckedPixmapRatio != contentsRect().size())
            m_uncheckedPixmap = cacheRendering(contentsRect().size(), false);
        p.drawPixmap(contentsRect(), m_uncheckedPixmap);
    }
    if (isDown()) {
        p.setPen(Qt::NoPen);
        p.setBrush(QColor(0, 0, 0, 20));
        p.drawRoundedRect(rect().adjusted(1, 1, -1, -1), 1, 1);
    }
}

QPixmap DetailsButton::cacheRendering(const QSize &size, bool checked)
{
    QLinearGradient lg;
    lg.setCoordinateMode(QGradient::ObjectBoundingMode);
    lg.setFinalStop(0, 1);

    qreal pixelRatio = 1.0;
#if QT_VERSION >= 0x050100
    pixelRatio = devicePixelRatio();
#endif
    QPixmap pixmap(size * pixelRatio);
#if QT_VERSION >= 0x050100
    pixmap.setDevicePixelRatio(pixelRatio);
#endif
    pixmap.fill(Qt::transparent);
    QPainter p(&pixmap);
    p.setRenderHint(QPainter::Antialiasing, true);
    p.translate(0.5, 0.5);
    p.setPen(Qt::NoPen);
    if (!checked) {
        lg.setColorAt(0, QColor(0, 0, 0, 10));
        lg.setColorAt(1, QColor(0, 0, 0, 16));
    } else {
        lg.setColorAt(0, QColor(255, 255, 255, 0));
        lg.setColorAt(1, QColor(255, 255, 255, 50));
    }

    p.setBrush(lg);
    p.setPen(QColor(255,255,255,140));
    p.drawRoundedRect(1, 1, size.width()-3, size.height()-3, 1, 1);
    p.setPen(QPen(QColor(0, 0, 0, 40)));
    p.drawLine(0, 1, 0, size.height() - 2);
    if (checked)
        p.drawLine(1, size.height() - 1, size.width() - 1, size.height() - 1);

    p.setPen(palette().color(QPalette::Text));

    QRect textRect = p.fontMetrics().boundingRect(text());
    textRect.setWidth(textRect.width() + 15);
    textRect.setHeight(textRect.height() + 4);
    textRect.moveCenter(rect().center());

    p.drawText(textRect, Qt::AlignLeft | Qt::AlignVCenter, text());

    int arrowsize = 15;
    QStyleOption arrowOpt;
    arrowOpt.initFrom(this);
    QPalette pal = arrowOpt.palette;
    pal.setBrush(QPalette::All, QPalette::Text, QColor(0, 0, 0));
    arrowOpt.rect = QRect(size.width() - arrowsize - 6, height()/2-arrowsize/2, arrowsize, arrowsize);
    arrowOpt.palette = pal;
    style()->drawPrimitive(checked ? QStyle::PE_IndicatorArrowUp : QStyle::PE_IndicatorArrowDown, &arrowOpt, &p, this);
    return pixmap;
}