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#include "qeglplatformscreen_p.h"
#include "qeglplatformwindow_p.h"
#include <QtGui/qwindow.h>
#include <qpa/qwindowsysteminterface.h>
#include <QtPlatformSupport/private/qopenglcompositor_p.h>

QT_BEGIN_NAMESPACE

/*!
    \class QEGLPlatformScreen
    \brief Base class for EGL-based platform screen implementations.
    \since 5.2
    \internal
    \ingroup qpa
 */

QEGLPlatformScreen::QEGLPlatformScreen(EGLDisplay dpy)
    : m_dpy(dpy),
      m_pointerWindow(0)
{
}

QEGLPlatformScreen::~QEGLPlatformScreen()
{
    QOpenGLCompositor::destroy();
}

void QEGLPlatformScreen::handleCursorMove(const QPoint &pos)
{
    const QOpenGLCompositor *compositor = QOpenGLCompositor::instance();
    const QList<QOpenGLCompositorWindow *> windows = compositor->windows();

    // Generate enter and leave events like a real windowing system would do.
    if (windows.isEmpty())
        return;

    // First window is always fullscreen.
    if (windows.count() == 1) {
        QWindow *window = windows[0]->sourceWindow();
        if (m_pointerWindow != window) {
            m_pointerWindow = window;
            QWindowSystemInterface::handleEnterEvent(window, window->mapFromGlobal(pos), pos);
        }
        return;
    }

    QWindow *enter = 0, *leave = 0;
    for (int i = windows.count() - 1; i >= 0; --i) {
        QWindow *window = windows[i]->sourceWindow();
        const QRect geom = window->geometry();
        if (geom.contains(pos)) {
            if (m_pointerWindow != window) {
                leave = m_pointerWindow;
                m_pointerWindow = window;
                enter = window;
            }
            break;
        }
    }

    if (enter && leave)
        QWindowSystemInterface::handleEnterLeaveEvent(enter, leave, enter->mapFromGlobal(pos), pos);
}

QPixmap QEGLPlatformScreen::grabWindow(WId wid, int x, int y, int width, int height) const
{
    QOpenGLCompositor *compositor = QOpenGLCompositor::instance();
    const QList<QOpenGLCompositorWindow *> windows = compositor->windows();
    Q_ASSERT(!windows.isEmpty());

    QImage img;

    if (static_cast<QEGLPlatformWindow *>(windows.first()->sourceWindow()->handle())->isRaster()) {
        // Request the compositor to render everything into an FBO and read it back. This
        // is of course slow, but it's safe and reliable. It will not include the mouse
        // cursor, which is a plus.
        img = compositor->grab();
    } else {
        // Just a single OpenGL window without compositing. Do not support this case for now. Doing
        // glReadPixels is not an option since it would read from the back buffer which may have
        // undefined content when calling right after a swapBuffers (unless preserved swap is
        // available and enabled, but we have no support for that).
        qWarning("grabWindow: Not supported for non-composited OpenGL content. Use QQuickWindow::grabWindow() instead.");
        return QPixmap();
    }

    if (!wid) {
        const QSize screenSize = geometry().size();
        if (width < 0)
            width = screenSize.width() - x;
        if (height < 0)
            height = screenSize.height() - y;
        return QPixmap::fromImage(img).copy(x, y, width, height);
    }

    foreach (QOpenGLCompositorWindow *w, windows) {
        const QWindow *window = w->sourceWindow();
        if (window->winId() == wid) {
            const QRect geom = window->geometry();
            if (width < 0)
                width = geom.width() - x;
            if (height < 0)
                height = geom.height() - y;
            QRect rect(geom.topLeft() + QPoint(x, y), QSize(width, height));
            rect &= window->geometry();
            return QPixmap::fromImage(img).copy(rect);
        }
    }

    return QPixmap();
}

QT_END_NAMESPACE