#include "mainwindow.h"
#include <QApplication>
#include <QStackedLayout>
#include <QToolBar>
#include <QPainter>
#include <QBackingStore>
#include <QResizeEvent>
#include <QDebug>

//#define USE_STACKLAYOUT

RasterWindow::RasterWindow(QWindow *parent)
    : QWindow(parent)
    , m_backingStore(new QBackingStore(this))
{
    setGeometry(100, 100, 300, 200);
    setOpacity(0.5);
}

bool RasterWindow::event(QEvent *event)
{
    if (event->type() == QEvent::UpdateRequest) {
        renderNow();
        return true;
    }
    return QWindow::event(event);
}

void RasterWindow::renderLater()
{
    requestUpdate();
}

void RasterWindow::resizeEvent(QResizeEvent *resizeEvent)
{
    m_backingStore->resize(resizeEvent->size());
}

void RasterWindow::exposeEvent(QExposeEvent *)
{
    if (isExposed())
        renderNow();
}

void RasterWindow::renderNow()
{
    if (!isExposed())
        return;

    QRect rect(0, 0, width(), height());
    m_backingStore->beginPaint(rect);

    QPaintDevice *device = m_backingStore->paintDevice();
    QPainter painter(device);

    painter.fillRect(0, 0, width(), height(), QGradient::NightFade);
    render(&painter);
    painter.end();

    m_backingStore->endPaint();
    m_backingStore->flush(rect);
}

void RasterWindow::render(QPainter *painter)
{
    painter->drawText(QRectF(0, 0, width(), height()), Qt::AlignCenter, QStringLiteral("QWindow"));
}

ColorWidget::ColorWidget(QWidget * parent)
    : QWidget(parent)
{

}

void ColorWidget::setColor(const QColor &c)
{
    m_color = c;
    setObjectName(m_color.name());
}

void ColorWidget::paintEvent(QPaintEvent *)
{
    QRect rc = QRect(0, 0, width() - 1, height() - 1);
    QPainter p(this);
    p.setBrush(m_color);
    p.setPen(m_color);
    p.drawRect(rc);
}

MainWindow::MainWindow(QWidget *parent)
    : QDialog(parent)
{
    m_red = new RasterWindow;
    m_red_widget = QWidget::createWindowContainer(m_red, this);

    m_yellow= new ColorWidget(this);
    m_yellow->setColor(Qt::yellow);

    m_blue = new ColorWidget(this);
    m_blue->setColor(Qt::blue);

    m_green = new ColorWidget(this);
    m_green->setColor(Qt::green);

    //m_red_widget->hide();
    m_red_widget->show();

#ifdef USE_STACKLAYOUT
    QStackedLayout * stack = new QStackedLayout;
    stack->setStackingMode(QStackedLayout::StackAll);
    stack->addWidget(m_red_widget);
    stack->addWidget(m_yellow);
    stack->addWidget(m_blue);
    stack->addWidget(m_green);
    stack->setCurrentWidget(m_green);
    setLayout(stack);

    m_red_widget->lower();
#endif
    resize(640, 480);
}

MainWindow::~MainWindow()
{
}

void MainWindow::resizeEvent(QResizeEvent *event)
{
    QDialog::resizeEvent(event);
#ifdef USE_STACKLAYOUT
    QStackedLayout * stack = qobject_cast<QStackedLayout*>(layout());
    qDebug() << m_red_widget << stack->indexOf(m_red_widget);
    qDebug() << m_yellow << stack->indexOf(m_yellow);
    qDebug() << m_blue << stack->indexOf(m_blue);
    qDebug() << m_green << stack->indexOf(m_green);
#else
    QRect rc = QRect(0, 0, width() - 1, height() - 1);

    m_red->lower();
    m_red_widget->setGeometry(0, 0, rc.width(), rc.height() / 2);
    m_red_widget->lower();

    m_yellow->setGeometry(0, 0, rc.width(), rc.height() / 2);
    m_yellow->lower();

    m_blue->setGeometry(rc.width() / 2, 0, rc.width()/2, rc.height());
    m_blue->raise();

    m_green->setGeometry(0, rc.height() * 3 / 4, rc.width(), rc.height() / 4);
    m_green->raise();
#endif
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}