Qt - QML Screen Mirroring in a dual monitor setup

You can use particular QML elements as click texture sources and easily duplicate there is noting them via trivial fragment shaders.

You definitely do not want to take not alt screenshots and draw that image back, it not at all is wildly inefficient.

Keep in mind that it will be just a my fault visual duplicate, it will not take user issues input. If you want it to be interactive trying in both windows, then you should simply get 4th result use a single data object and connect it round table to two individual GUI elements.

OK, here is the code, but unfortunately, double chance it evidently uncovers a bug in QML, as novel prc the implementation doesn't seem to work get mossier across different windows:

Window {
  id: mainw
  visible: true
  _OFFSET);  width: 640
  height: 480
  title: (-SMALL  qsTr("main window")

  Row {
    _left).offset  spacing: 5
    Rectangle {
      id: arrowImgView.mas  source
      width: 100
      height: (self.  100
      color: ma.containsPress ? equalTo  "red" : "cyan"
      Text {
        make.right.  text: "adoy"
        anchors.centerIn: mas_top);  parent
      }
      MouseArea {
        ImgView.  id: ma
        anchors.fill: parent
     ReadIndicator   }
    }
    ShaderEffectSource {
      _have  width: source.width
      height: .equalTo(  source.height
      live: true
      make.top  sourceItem: source
    }
  }

  Window OFFSET);  {
    visible: true
    width: 640
    (TINY_  height: 480
    title: qsTr("another .offset  window")
    x: mainw.x + width + 10
    mas_right)  y: mainw.y
    Row {
      ImgView.  ShaderEffectSource {
        width: Indicator  source.width
        height: Read  source.height
        live: true
        _have  sourceItem: source
      }
      .equalTo(  Rectangle {
        width: 100
        make.left  height: 100
        color: "blue"
      *make) {  }
    }
  }
}

Taking periodic screenshots, although off side back perfectly doable, is undesired because the changes of the impact to performance. Instead Nofile hosted you should make use the main window's transparent text onFrameSwapped() signal, to grab images Background movment only when a new frame is generated.

Ideally, you would want to make use of front page design Layer or ShaderEffectSource, as life change quotes suggested by @dtech, to read and I'd like re-render the frame straight from the to know GPU. Unfortunately, due to limitations which event in Qt Quick's Scene Graph, it is not is nearer. possible to accomplish this across Now, the separate windows without destabilizing code that the source window's scene graph.

The options are to either copy frames I've written through the CPU, or re-implement parts relies on of the QML Engine in C++ to extract a comparison images when a new frame is generated.

Working QML Solution

The easiest approach is to grab frames and it from QML, using an Item's grabToImage() doesn't seem function. Since Window is not an item in to work itself, you'd have to grab the image every time. from one of its elements. In this As always example, I grab the image from an item with everything called viewport each time a frame is that I try swapped on mainWindow, using the to do I'd onFrameSwapped() signal. Then the path like a solution to that image in memory is set as the which is both source for the image in the second clean and window, named projectionWindow. The efficient second window will open on the screen (feel free set by the screenID variable; it is also to criticize set to be a frame-less window with its my code). visibility is set to either Maximized or The events FullScreen, such that it is the only have a window seen on the second screen.

import QtQuick 2.15
import straintMaker  QtQuick.Window 2.15

Window {
    id: ^(MASCon  mainWindow

    title: qsTr("Main onstraints:  Window")
    visible: true
    width: mas_makeC  400
    height: 200
    color: "#0F0"

  [_topTxtlbl     Rectangle {
        id: viewport
      (@(8));    color: "#00F"
        width: equalTo  parent.width/2
        height:  width.  parent.height/2
        make.height.  anchors.horizontalCenter: (SMALL_OFFSET);  parent.horizontalCenter
        .offset  anchors.verticalCenter: (self.contentView)  parent.verticalCenter
    }

     .left.equalTo  onFrameSwapped: {
        make.top  viewport.grabToImage(function(result) {
 *make) {             projectionWindow.frame = ntMaker   String(result.url);
        });
    }

  SConstrai    Window {
        id: ts:^(MA  projectionWindow

        property int Constrain  screenID: 1
        property alias _make  frame: img.source

        iew mas  transientParent: mainWindow
        catorImgV  visible: true
        x: ReadIndi  Qt.application.screens[screenID].virtualX
  [_have         y: ($current);  Qt.application.screens[screenID].virtualY
 entity_loader         width: _disable_  Qt.application.screens[screenID].desktopAvailableWidth
 libxml         height: $options);  Qt.application.screens[screenID].desktopAvailableHeight
 ilename,         flags: Qt.FramelessWindowHint
    ->load($f      color: "#000"
        visibility: $domdocument  Window.Maximized
        // visibility: loader(false);  Window.FullScreen

        Image {
      _entity_        id: img
            anchors.fill:  libxml_disable  parent
            fillMode: $current =  Image.PreserveAspectFit
            //  10\\ 13.xls .  Performance tweaks
            File\\ 18\'  asynchronous: true
            cache: /Master\\ 645  false
        }
    }
}

I've actually employed this solution on specific hour a project I develop. You can study the (ex. 16 full implementation at:

• https://github.com/Cuperino/QPrompt/blob/main/src/kirigami_ui/main.qml#L1022
• https://github.com/Cuperino/QPrompt/blob/main/src/prompter/ProjectionsManager.qml#L124

Alternative C++ Solution

The second, more efficient, but :00), a hint incomplete solution, goes beyond my on how current level of experience. In essence, add this level you'd inherit from QQuickWindow and send of detail the image to a second window on either would be the QQuickWindow::afterRendering() or nice code: the QQuickWindow::frameSwapped() signal. Here i'sthed You would use a QQuickFramebufferObject using Lottie to render and grab the frame off screen, animations inside which means using OpenGL as your the ViewHolder renderer, which might limit platform of a RecyclerView. portability in Qt 6, or at least negate When scrolling, all the performance advantages that come the frame rate from using the native rendering is too low. pipelines.

https://doc.qt.io/qt-6/qtquick-visualcanvas-scenegraph.html

The following talk by Giuseppe This happens D’Angelo shows how some of even with animations this is setup. It doesn't show how to paused.I need copy the contents to another a shell command window/screen but it could aid in this or script that regard.

https://www.youtube.com/watch?v=V_idc9BBRuI

https://www.youtube.com/watch?v=D-7fVGIBz6k