path: root/src/plugins/platforms/windows/qwindowsscreen.cpp

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#include "qwindowsscreen.h"
#include "qwindowscontext.h"
#include "qwindowswindow.h"
#include "qwindowsintegration.h"
#include "qwindowscursor.h"
#include "qwindowscontext.h"

#include "qtwindows_additional.h"

#include <QtGui/QPixmap>
#include <QtGui/QGuiApplication>
#include <QtGui/QWindowSystemInterface>
#include <QtGui/QScreen>

#include <QtCore/QDebug>

QT_BEGIN_NAMESPACE

QWindowsScreenData::QWindowsScreenData() :
    dpi(96, 96), depth(32), format(QImage::Format_ARGB32_Premultiplied),
    flags(VirtualDesktop), orientation(Qt::LandscapeOrientation)
{
}

static inline QDpi deviceDPI(HDC hdc)
{
    return QDpi(GetDeviceCaps(hdc, LOGPIXELSX), GetDeviceCaps(hdc, LOGPIXELSY));
}

static inline QSizeF deviceSizeMM(const QSize &pixels, const QDpi &dpi)
{
    const qreal inchToMM = 25.4;
    const qreal h = qreal(pixels.width())  / qreal(dpi.first)  * inchToMM;
    const qreal v = qreal(pixels.height()) / qreal(dpi.second) * inchToMM;
    return QSizeF(h, v);
}

static inline QDpi deviceDPI(const QSize &pixels, const QSizeF &physicalSizeMM)
{
    const qreal inchToMM = 25.4;
    const qreal h = qreal(pixels.width())  / (qreal(physicalSizeMM.width())  / inchToMM);
    const qreal v = qreal(pixels.height()) / (qreal(physicalSizeMM.height()) / inchToMM);
    return QDpi(h, v);
}

typedef QList<QWindowsScreenData> WindowsScreenDataList;

// from QDesktopWidget, taking WindowsScreenDataList as LPARAM
BOOL QT_WIN_CALLBACK monitorEnumCallback(HMONITOR hMonitor, HDC, LPRECT, LPARAM p)
{
    MONITORINFOEX info;
    memset(&info, 0, sizeof(MONITORINFOEX));
    info.cbSize = sizeof(MONITORINFOEX);
    if (GetMonitorInfo(hMonitor, &info) == FALSE)
        return TRUE;

    WindowsScreenDataList *result = reinterpret_cast<WindowsScreenDataList *>(p);
    QWindowsScreenData data;
    data.geometry = QRect(QPoint(info.rcMonitor.left, info.rcMonitor.top), QPoint(info.rcMonitor.right - 1, info.rcMonitor.bottom - 1));
    if (HDC hdc = CreateDC(info.szDevice, NULL, NULL, NULL)) {
        data.dpi = deviceDPI(hdc);
        data.depth = GetDeviceCaps(hdc, BITSPIXEL);
        data.format = data.depth == 16 ? QImage::Format_RGB16 : QImage::Format_RGB32;
        data.physicalSizeMM = QSizeF(GetDeviceCaps(hdc, HORZSIZE), GetDeviceCaps(hdc, VERTSIZE));
        DeleteDC(hdc);
    } else {
        qWarning("%s: Unable to obtain handle for monitor '%s', defaulting to %g DPI.",
                 __FUNCTION__, qPrintable(QString::fromWCharArray(info.szDevice)),
                 data.dpi.first);
    }
    data.geometry = QRect(QPoint(info.rcMonitor.left, info.rcMonitor.top), QPoint(info.rcMonitor.right - 1, info.rcMonitor.bottom - 1));
    data.availableGeometry = QRect(QPoint(info.rcWork.left, info.rcWork.top), QPoint(info.rcWork.right - 1, info.rcWork.bottom - 1));
    data.orientation = data.geometry.height() > data.geometry.width() ?
                       Qt::PortraitOrientation : Qt::LandscapeOrientation;
    // EnumDisplayMonitors (as opposed to EnumDisplayDevices) enumerates only
    // virtual desktop screens.
    data.flags = QWindowsScreenData::VirtualDesktop;
    if (info.dwFlags & MONITORINFOF_PRIMARY)
        data.flags |= QWindowsScreenData::PrimaryScreen;
    data.name = QString::fromWCharArray(info.szDevice);
    result->append(data);
    return TRUE;
}

static inline WindowsScreenDataList monitorData()
{
    WindowsScreenDataList result;
    EnumDisplayMonitors(0, 0, monitorEnumCallback, (LPARAM)&result);
    return result;
}

static QDebug operator<<(QDebug dbg, const QWindowsScreenData &d)
{
    QDebug nospace =  dbg.nospace();
    nospace << "Screen " << d.name << ' '
            << d.geometry.width() << 'x' << d.geometry.height() << '+' << d.geometry.x() << '+' << d.geometry.y()
            << " avail: "
            << d.availableGeometry.width() << 'x' << d.availableGeometry.height() << '+' << d.availableGeometry.x() << '+' << d.availableGeometry.y()
            << " physical: " << d.physicalSizeMM.width() <<  'x' << d.physicalSizeMM.height()
            << " DPI: " << d.dpi.first << 'x' << d.dpi.second << " Depth: " << d.depth
            << " Format: " << d.format;
    if (d.flags & QWindowsScreenData::PrimaryScreen)
        nospace << " primary";
    if (d.flags & QWindowsScreenData::VirtualDesktop)
        nospace << " virtual desktop";
    return dbg;
}

/*!
    \class QWindowsScreen
    \brief Windows screen.
    \ingroup qt-lighthouse-win
    \sa QWindowsScreenManager
*/

QWindowsScreen::QWindowsScreen(const QWindowsScreenData &data) :
    m_data(data), m_cursor(this)
{
}

QPixmap QWindowsScreen::grabWindow(WId window, int x, int y, int width, int height) const
{
    Q_GUI_EXPORT QPixmap qt_pixmapFromWinHBITMAP(HBITMAP bitmap, int hbitmapFormat = 0);

    if (QWindowsContext::verboseIntegration)
        qDebug() << __FUNCTION__ << window << x << y << width << height;
    RECT r;
    HWND hwnd = (HWND)window;
    GetClientRect(hwnd, &r);

    if (width < 0) width = r.right - r.left;
    if (height < 0) height = r.bottom - r.top;

    // Create and setup bitmap
    HDC display_dc = GetDC(0);
    HDC bitmap_dc = CreateCompatibleDC(display_dc);
    HBITMAP bitmap = CreateCompatibleBitmap(display_dc, width, height);
    HGDIOBJ null_bitmap = SelectObject(bitmap_dc, bitmap);

    // copy data
    HDC window_dc = GetDC(hwnd);
    BitBlt(bitmap_dc, 0, 0, width, height, window_dc, x, y, SRCCOPY | CAPTUREBLT);

    // clean up all but bitmap
    ReleaseDC(hwnd, window_dc);
    SelectObject(bitmap_dc, null_bitmap);
    DeleteDC(bitmap_dc);

    const QPixmap pixmap = qt_pixmapFromWinHBITMAP(bitmap);

    DeleteObject(bitmap);
    ReleaseDC(0, display_dc);

    return pixmap;
}

/*!
    \brief Find a top level window taking the flags of ChildWindowFromPointEx.
*/

QWindow *QWindowsScreen::findTopLevelAt(const QPoint &point, unsigned flags)
{
    QWindow* result = 0;
    if (QPlatformWindow *bw = QWindowsContext::instance()->
            findPlatformWindowAt(GetDesktopWindow(), point, flags))
        result = QWindowsWindow::topLevelOf(bw->window());
    if (QWindowsContext::verboseWindows)
        qDebug() << __FUNCTION__ << point << flags << result;
    return result;
}

QWindow *QWindowsScreen::windowAt(const QPoint &screenPoint, unsigned flags)
{
    QWindow* result = 0;
    if (QPlatformWindow *bw = QWindowsContext::instance()->
            findPlatformWindowAt(GetDesktopWindow(), screenPoint, flags))
        result = bw->window();
    if (QWindowsContext::verboseWindows)
        qDebug() << __FUNCTION__ << screenPoint << " returns " << result;
    return result;
}

QWindow *QWindowsScreen::windowUnderMouse(unsigned flags)
{
    return QWindowsScreen::windowAt(QWindowsCursor::mousePosition(), flags);
}

QWindowsScreen *QWindowsScreen::screenOf(const QWindow *w)
{
    if (w)
        if (const QScreen *s = w->screen())
            if (QPlatformScreen *pscr = s->handle())
                return static_cast<QWindowsScreen *>(pscr);
    if (const QScreen *ps = QGuiApplication::primaryScreen())
        if (QPlatformScreen *ppscr = ps->handle())
            return static_cast<QWindowsScreen *>(ppscr);
    return 0;
}

/*!
    \brief Determine siblings in a virtual desktop system.

    Self is by definition a sibling, else collect all screens
    within virtual desktop.
*/

QList<QPlatformScreen *> QWindowsScreen::virtualSiblings() const
{
    QList<QPlatformScreen *> result;
    if (m_data.flags & QWindowsScreenData::VirtualDesktop) {
        foreach (QWindowsScreen *screen, QWindowsContext::instance()->screenManager().screens())
            if (screen->data().flags & QWindowsScreenData::VirtualDesktop)
                result.push_back(screen);
    } else {
        result.push_back(const_cast<QWindowsScreen *>(this));
    }
    return result;
}

/*!
    \brief Notify QWindowSystemInterface about changes of a screen and synchronize data.
*/

void QWindowsScreen::handleChanges(const QWindowsScreenData &newData)
{
    if (m_data.geometry != newData.geometry) {
        m_data.geometry = newData.geometry;
        QWindowSystemInterface::handleScreenGeometryChange(screen(),
                                                           newData.geometry);
    }
    if (m_data.availableGeometry != newData.availableGeometry) {
        m_data.availableGeometry = newData.availableGeometry;
        QWindowSystemInterface::handleScreenAvailableGeometryChange(screen(),
                                                                    newData.availableGeometry);
    }
    if (!qFuzzyCompare(m_data.dpi.first, newData.dpi.first)
        || !qFuzzyCompare(m_data.dpi.second, newData.dpi.second)) {
        m_data.dpi = newData.dpi;
        QWindowSystemInterface::handleScreenLogicalDotsPerInchChange(screen(),
                                                                     newData.dpi.first,
                                                                     newData.dpi.second);
    }
    if (m_data.orientation != newData.orientation) {
        m_data.orientation = newData.orientation;
        QWindowSystemInterface::handleScreenOrientationChange(screen(),
                                                              newData.orientation);
    }
}

/*!
    \class QWindowsScreenManager
    \brief Manages a list of QWindowsScreen.

    Listens for changes and notifies QWindowSystemInterface about changed/
    added/deleted screens.

    \ingroup qt-lighthouse-win
    \sa QWindowsScreen
*/

QWindowsScreenManager::QWindowsScreenManager() :
    m_lastDepth(-1), m_lastHorizontalResolution(0), m_lastVerticalResolution(0)
{
}

/*!
    \brief Triggers synchronization of screens (WM_DISPLAYCHANGE).

    Subsequent events are compressed since WM_DISPLAYCHANGE is sent to
    each top level window.
*/

bool QWindowsScreenManager::handleDisplayChange(WPARAM wParam, LPARAM lParam)
{
    const int newDepth = (int)wParam;
    const WORD newHorizontalResolution = LOWORD(lParam);
    const WORD newVerticalResolution = HIWORD(lParam);
    if (newDepth != m_lastDepth || newHorizontalResolution != m_lastHorizontalResolution
        || newVerticalResolution != m_lastVerticalResolution) {
        m_lastDepth = newDepth;
        m_lastHorizontalResolution = newHorizontalResolution;
        m_lastVerticalResolution = newVerticalResolution;
        if (QWindowsContext::verboseWindows)
            qDebug("%s: Depth=%d, resolution=%hux%hu",
                   __FUNCTION__, newDepth, newHorizontalResolution, newVerticalResolution);
        handleScreenChanges();
    }
    return false;
}

static inline int indexOfMonitor(const QList<QWindowsScreen *> &screens,
                                 const QString &monitorName)
{
    for (int i= 0; i < screens.size(); ++i)
        if (screens.at(i)->data().name == monitorName)
            return i;
    return -1;
}

static inline int indexOfMonitor(const QList<QWindowsScreenData> &screenData,
                                 const QString &monitorName)
{
    for (int i = 0; i < screenData.size(); ++i)
        if (screenData.at(i).name == monitorName)
            return i;
    return -1;
}

/*!
    \brief Synchronizes the screen list, adds new screens, removes deleted
    ones and propagates resolution changes to QWindowSystemInterface.
*/

void QWindowsScreenManager::handleScreenChanges()
{
    // Look for changed monitors, add new ones
    const WindowsScreenDataList newDataList = monitorData();
    foreach (const QWindowsScreenData &newData, newDataList) {
        const int existingIndex = indexOfMonitor(m_screens, newData.name);
        if (existingIndex != -1) {
            m_screens.at(existingIndex)->handleChanges(newData);
        } else {
            QWindowsScreen *newScreen = new QWindowsScreen(newData);
            m_screens.push_back(newScreen);
            QWindowsIntegration::instance()->emitScreenAdded(newScreen);
            if (QWindowsContext::verboseWindows)
                qDebug() << "New Monitor: " << newData;
        }    // exists
    }        // for new screens.
    // Remove deleted ones.
    for (int i = m_screens.size() - 1; i >= 0; --i) {
        if (indexOfMonitor(newDataList, m_screens.at(i)->data().name) == -1) {
            if (QWindowsContext::verboseWindows)
                qDebug() << "Removing Monitor: " << m_screens.at(i) ->data();
            delete m_screens.takeAt(i);
        } // not found
    }     // for existing screens
}

QT_END_NAMESPACE