Cant get Screenshot of Desktop right as Widget-Background

[gerdb]

Hi,

i tried to get the desktop as screenshot and then display exactly the part of it which my widget/window overlaps in the widget's background.

i work on a pc with 2 monitors and get different result ( both are broken ) for each

Left Monitor (primary):

- Image gets distorted on Window resize
- Image contains the widget itself, and i dont know how to hide it during screenshoting the desktop

i tried hide, get screenshot, show with setUpdateEnabled false and true again, but some events still are fired -> infinite loop, bad crash

Right Monitor:

- cant copy part of Screenshot, it is always the full screenshot as widget-background

So my most important questions will be:

1. How do i hide and show widget without getting floods of event, signals
2. How do i get the QScreen object from the widget position
3. What are your opinions/suggestions

TransparentPanel.h

#include <QWidget>
#include <QPixmap>
 
// ============================================================================
/// @class TransparentPanel
// ============================================================================
 
class TransparentPanel : public QWidget
{
    Q_OBJECT
public:
private:
    QPixmap mBG;
 
public:
    ///@brief Constructor
    explicit TransparentPanel( QWidget* parent = 0 );
 
    ///@brief Destructor
    ~TransparentPanel();
 
    void updateBG();
 
protected:
    virtual void paintEvent( QPaintEvent* event ) override;
    virtual void resizeEvent(QResizeEvent* event) override;
    virtual void moveEvent( QMoveEvent* event) override;
//    virtual void enterEvent( QEvent* event ) override;
//    virtual void leaveEvent( QEvent* event ) override;
//    virtual void mousePressEvent ( QMouseEvent* event );
//    virtual void mouseReleaseEvent ( QMouseEvent* event );
 
};

#include <QWidget>
#include <QPixmap>

// ============================================================================
/// @class TransparentPanel
// ============================================================================

class TransparentPanel : public QWidget
{
    Q_OBJECT
public:
private:
    QPixmap mBG;

public:
    ///@brief Constructor
    explicit TransparentPanel( QWidget* parent = 0 );

    ///@brief Destructor
    ~TransparentPanel();

    void updateBG();

protected:
    virtual void paintEvent( QPaintEvent* event ) override;
    virtual void resizeEvent(QResizeEvent* event) override;
    virtual void moveEvent( QMoveEvent* event) override;
//    virtual void enterEvent( QEvent* event ) override;
//    virtual void leaveEvent( QEvent* event ) override;
//    virtual void mousePressEvent ( QMouseEvent* event );
//    virtual void mouseReleaseEvent ( QMouseEvent* event );

};

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TransparentPanel.cpp

#include "TransparentPanel.h"
 
#ifndef VERBOSE
#define VERBOSE 1
#endif
 
#include <QPainter>
#include <QMouseEvent>
#include <QApplication>
#include <QDesktopWidget>
#include <QScreen>
#include <QDebug>
 
// ============================================================================
TransparentPanel::TransparentPanel( QWidget* parent )
    : QWidget(parent)
// ============================================================================
{
    setMinimumSize(10,10);
    setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
    setAutoFillBackground( false );
    //setAttribute( Qt::WA_OpaquePaintEvent );
    setAttribute( Qt::WA_NoSystemBackground );
    //setAttribute( Qt::WA_TranslucentBackground );
    setUpdatesEnabled( true );
 
    //MMDebug("TransparentPanel::TransparentPanel()\n")
    //MMDebug("QApplication::desktop()->winId() = %x\n", (void*)QApplication::desktop()->winId() )
    //MMDebug("GetDesktopWindow() = %x\n", (void*)GetDesktopWindow() )
    updateBG();
}
 
// ============================================================================
TransparentPanel::~TransparentPanel()
// ============================================================================
{
    //MMDebug("TransparentPanel::~TransparentPanel()\n")
}
 
// ============================================================================
void TransparentPanel::paintEvent( QPaintEvent* event )
// ============================================================================
{
    if (!isVisible())
        return;
 
    //MMDebug("TransparentPanel::paintEvent()\n")
 
    QPainter dc(this);
    dc.setRenderHint( QPainter::NonCosmeticDefaultPen );
 
    //dc.fillRect( rect(), Qt::white);
    if (!mBG.isNull())
    {
        dc.drawPixmap( rect(), mBG);
    }
 
    QWidget::paintEvent(event);
}
 
// ============================================================================
void TransparentPanel :: resizeEvent(QResizeEvent* event)
// ============================================================================
{
    //MMDebug("TransparentPanel::resizeEvent()\n")
    updateBG();
    //QWidget::resizeEvent(event);
}
 
// ============================================================================
void TransparentPanel::moveEvent( QMoveEvent* event)
// ============================================================================
{
    //MMDebug("TransparentPanel::moveEvent()\n")
    updateBG();
    //QWidget::moveEvent(event);
}
 
//// ============================================================================
//void TransparentPanel::enterEvent( QEvent* event )
//// ============================================================================
//{
//    QWidget::enterEvent(event);
//}
 
//// ============================================================================
//void TransparentPanel::leaveEvent( QEvent* event )
//// ============================================================================
//{
//    QWidget::leaveEvent(event);
//}
 
//// ============================================================================
//void TransparentPanel :: mousePressEvent ( QMouseEvent* event )
//// ============================================================================
//{
//    QWidget::mousePressEvent( event );
//}
 
//// ============================================================================
//void TransparentPanel :: mouseReleaseEvent ( QMouseEvent* event )
//// ============================================================================
//{
//    QWidget::mouseReleaseEvent( event );
//}
 
 
// ============================================================================
void TransparentPanel::updateBG()
// ============================================================================
{
//    if (!isVisible())
//        return;
 
////    setVisible(false);
//    mBG = QPixmap(); // clear image for low memory situations on weak devices.
//    QPoint screenTopLeft = mapToGlobal( geometry().topLeft() );
//    int x = screenTopLeft.x();
//    int y = screenTopLeft.y();
//    int w = width();
//    int h = height();
//    //mBG = QPixmap::grabWindow(QApplication::desktop()->winId(), x,y, w,h );
 
//    //QScreen* screen = QApplication::screens()->primaryScreen();
//    QScreen* screen = QApplication::primaryScreen();
//    if (screen)
//     //mBG = screen->grabWindow(QApplication::desktop()->window()->winId(), x,y, w,h );
//        mBG = screen->grabWindow((WId)GetDesktopWindow(), x,y, w,h );
 
////    setVisible(true);
//    update();
 
    QRect g = geometry();
    QPoint p1 = mapToGlobal( g.topLeft() );
    QPoint p2 = mapToGlobal( g.bottomRight() );
 
//    setVisible(false);
    QPoint screenTopLeft = mapToGlobal( pos() );
    int ax = screenTopLeft.x();
    int ay = screenTopLeft.y();
    int aw = width();
    int ah = height();
 
    QRect r( p1, p2 );
 
//    QImage img = pix.toImage();
//    for ( int j = 0; j < img.height(); ++j )
//    {
//        for ( int i = 0; i < img.width(); ++i )
//        {
//            QColor c = img.pixel(i,j);
//            c.setAlpha(255);
//            img.setPixel( i,j, c.rgba() );
//        }
//    }
 
//    //QImage img = pix.toImage();
//    dc.drawImage( rect(), img );
 
//    setUpdatesEnabled(false);
//    hide();
    //QPixmap pix = QDesktopWidget().grab( QRect(x,y,w,h) );
    //QPixmap pix = QPixmap::grabWindow(QApplication::desktop()->winId(), x,y, w,h );
    //QPixmap screenShot = QApplication::primaryScreen()->grabWindow( (WId)GetDesktopWindow() );
    //mBG = screenShot.copy( ax,ay,aw,ah );
    //mBG = screenShot.copy( r );
 
//    mBG = QApplication::primaryScreen()->grabWindow( (WId)GetDesktopWindow(), r.left(), r.top(), r.width(), r.height() );
 
    QPixmap scr = QApplication::primaryScreen()->grabWindow( (WId)GetDesktopWindow() );
    mBG = scr.copy( r );
 
 
 
#ifdef VERBOSE
    std::stringstream s;
    s   << "pos ( x=" << pos().x() << ",y=" << pos().y() << ")\n";
    s   << "a ( x=" << ax << ",y=" << ay << ",w=" << aw << ",h=" << ah << ")\n";
    s   << "g ( x=" << g.left() << ",y=" << g.top() << ",w=" << g.width() << ",h=" << g.height() << ")\n";
    s   << "r ( x=" << r.left() << ",y=" << r.top() << ",w=" << r.width() << ",h=" << r.height() << ")\n";
    s   << "scr ( w=" << scr.width() << ",h=" << scr.height() << ")\n";
    s   << "mBG ( w=" << mBG.width() << ",h=" << mBG.height() << ")\n";
    qDebug() << QString::fromStdString(s.str());
    //MMPrint("%s", s.str().c_str())
#endif
 
//    show();
//    setUpdatesEnabled(true);
    update();
}

#include "TransparentPanel.h"

#ifndef VERBOSE
#define VERBOSE 1
#endif

#include <QPainter>
#include <QMouseEvent>
#include <QApplication>
#include <QDesktopWidget>
#include <QScreen>
#include <QDebug>

// ============================================================================
TransparentPanel::TransparentPanel( QWidget* parent )
    : QWidget(parent)
// ============================================================================
{
    setMinimumSize(10,10);
    setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
    setAutoFillBackground( false );
    //setAttribute( Qt::WA_OpaquePaintEvent );
    setAttribute( Qt::WA_NoSystemBackground );
    //setAttribute( Qt::WA_TranslucentBackground );
    setUpdatesEnabled( true );

    //MMDebug("TransparentPanel::TransparentPanel()\n")
    //MMDebug("QApplication::desktop()->winId() = %x\n", (void*)QApplication::desktop()->winId() )
    //MMDebug("GetDesktopWindow() = %x\n", (void*)GetDesktopWindow() )
    updateBG();
}

// ============================================================================
TransparentPanel::~TransparentPanel()
// ============================================================================
{
    //MMDebug("TransparentPanel::~TransparentPanel()\n")
}

// ============================================================================
void TransparentPanel::paintEvent( QPaintEvent* event )
// ============================================================================
{
    if (!isVisible())
        return;

    //MMDebug("TransparentPanel::paintEvent()\n")

    QPainter dc(this);
    dc.setRenderHint( QPainter::NonCosmeticDefaultPen );

    //dc.fillRect( rect(), Qt::white);
    if (!mBG.isNull())
    {
        dc.drawPixmap( rect(), mBG);
    }

    QWidget::paintEvent(event);
}

// ============================================================================
void TransparentPanel :: resizeEvent(QResizeEvent* event)
// ============================================================================
{
    //MMDebug("TransparentPanel::resizeEvent()\n")
    updateBG();
    //QWidget::resizeEvent(event);
}

// ============================================================================
void TransparentPanel::moveEvent( QMoveEvent* event)
// ============================================================================
{
    //MMDebug("TransparentPanel::moveEvent()\n")
    updateBG();
    //QWidget::moveEvent(event);
}

//// ============================================================================
//void TransparentPanel::enterEvent( QEvent* event )
//// ============================================================================
//{
//    QWidget::enterEvent(event);
//}

//// ============================================================================
//void TransparentPanel::leaveEvent( QEvent* event )
//// ============================================================================
//{
//    QWidget::leaveEvent(event);
//}

//// ============================================================================
//void TransparentPanel :: mousePressEvent ( QMouseEvent* event )
//// ============================================================================
//{
//    QWidget::mousePressEvent( event );
//}

//// ============================================================================
//void TransparentPanel :: mouseReleaseEvent ( QMouseEvent* event )
//// ============================================================================
//{
//    QWidget::mouseReleaseEvent( event );
//}


// ============================================================================
void TransparentPanel::updateBG()
// ============================================================================
{
//    if (!isVisible())
//        return;

////    setVisible(false);
//    mBG = QPixmap(); // clear image for low memory situations on weak devices.
//    QPoint screenTopLeft = mapToGlobal( geometry().topLeft() );
//    int x = screenTopLeft.x();
//    int y = screenTopLeft.y();
//    int w = width();
//    int h = height();
//    //mBG = QPixmap::grabWindow(QApplication::desktop()->winId(), x,y, w,h );

//    //QScreen* screen = QApplication::screens()->primaryScreen();
//    QScreen* screen = QApplication::primaryScreen();
//    if (screen)
//     //mBG = screen->grabWindow(QApplication::desktop()->window()->winId(), x,y, w,h );
//        mBG = screen->grabWindow((WId)GetDesktopWindow(), x,y, w,h );

////    setVisible(true);
//    update();

    QRect g = geometry();
    QPoint p1 = mapToGlobal( g.topLeft() );
    QPoint p2 = mapToGlobal( g.bottomRight() );

//    setVisible(false);
    QPoint screenTopLeft = mapToGlobal( pos() );
    int ax = screenTopLeft.x();
    int ay = screenTopLeft.y();
    int aw = width();
    int ah = height();

    QRect r( p1, p2 );

//    QImage img = pix.toImage();
//    for ( int j = 0; j < img.height(); ++j )
//    {
//        for ( int i = 0; i < img.width(); ++i )
//        {
//            QColor c = img.pixel(i,j);
//            c.setAlpha(255);
//            img.setPixel( i,j, c.rgba() );
//        }
//    }

//    //QImage img = pix.toImage();
//    dc.drawImage( rect(), img );

//    setUpdatesEnabled(false);
//    hide();
    //QPixmap pix = QDesktopWidget().grab( QRect(x,y,w,h) );
    //QPixmap pix = QPixmap::grabWindow(QApplication::desktop()->winId(), x,y, w,h );
    //QPixmap screenShot = QApplication::primaryScreen()->grabWindow( (WId)GetDesktopWindow() );
    //mBG = screenShot.copy( ax,ay,aw,ah );
    //mBG = screenShot.copy( r );

//    mBG = QApplication::primaryScreen()->grabWindow( (WId)GetDesktopWindow(), r.left(), r.top(), r.width(), r.height() );

    QPixmap scr = QApplication::primaryScreen()->grabWindow( (WId)GetDesktopWindow() );
    mBG = scr.copy( r );



#ifdef VERBOSE
    std::stringstream s;
    s   << "pos ( x=" << pos().x() << ",y=" << pos().y() << ")\n";
    s   << "a ( x=" << ax << ",y=" << ay << ",w=" << aw << ",h=" << ah << ")\n";
    s   << "g ( x=" << g.left() << ",y=" << g.top() << ",w=" << g.width() << ",h=" << g.height() << ")\n";
    s   << "r ( x=" << r.left() << ",y=" << r.top() << ",w=" << r.width() << ",h=" << r.height() << ")\n";
    s   << "scr ( w=" << scr.width() << ",h=" << scr.height() << ")\n";
    s   << "mBG ( w=" << mBG.width() << ",h=" << mBG.height() << ")\n";
    qDebug() << QString::fromStdString(s.str());
    //MMPrint("%s", s.str().c_str())
#endif

//    show();
//    setUpdatesEnabled(true);
    update();
}

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[wysota]

1. How do i hide and show widget without getting floods of event, signals

By calling hide() and show() respectively.

2. How do i get the QScreen object from the widget position

No idea what you mean,.

[gerdb]

Hi,

1.) i did add hide(); command before getting screenshot and right after that i called show();

--> Results in crash ( as i already said )

2.) When i take the screenshot

aka QPixmap scr = QApplication:rimaryScreen()->grabWindow( (WId)GetDesktopWindow() );

i get a 1920x1080 pixels, meaning that it is only one of my monitors and not both, thatswhy i assumed the screenshot is taken monitor-wise

and i wanna know how to determine the current monitor where the widgets is one and take the screenshot from that monitor?

Is that more clear?

Thx in advance

[wysota]

Hi,

1.) i did add hide(); command before getting screenshot and right after that i called show();

--> Results in crash ( as i already said )

You said you called setUpdatesEnabled(false). That's something completely different to calling hide().

2.) When i take the screenshot

aka QPixmap scr = QApplication:rimaryScreen()->grabWindow( (WId)GetDesktopWindow() );

i get a 1920x1080 pixels, meaning that it is only one of my monitors and not both, thatswhy i assumed the screenshot is taken monitor-wise

and i wanna know how to determine the current monitor where the widgets is one and take the screenshot from that monitor?

Hmm... QWindow::screen()?

[PKEv]

Can you solve problem?
i use full construction:

QRect systemScreenRect = getSystemScreenRect();
return QApplication::screens().at(1)->grabWindow(0,0,0,
systemScreenRect.width(),
systemScreenRect.height());

but problem not solved full