Some trouble with high DPI

jeanmilost

Using Qt 5.15.2, I created a Qt Quick 2.0 application. The app is contained in a borderless non-resizeable window, and is planned to support the high DPI features. However I have some trouble, especially when I have several monitors with different DPI settings.

There are several situations.

1 - I open my borderless window onto a 120 dpi monitor:

Then I move it onto a 96 dpi monitor:

As you can see, the window size changes, but its content isn't resized

2- I add a frame to my window, and I open it onto a 120 dpi monitor:

Now I move it onto a 96 dpi monitor:

Then I move it back to the 120 dpi monitor:

This time, the content is resized too large in relation to my window.

I also get strange logs I cannot figure out, like the following:
QWindowsWindow::setGeometry: Unable to set geometry 400x728+3574+161 (frame: 416x767+3566+130) on CommandListForm_QMLTYPE_194/"" on "\.\DISPLAY1". Resulting geometry: 504x920+3574+161 (frame: 520x959+3566+130) margins: 8, 31, 8, 8) - qwindowswindow.cpp:1891, void __cdecl QWindowsWindow::setGeometry(const class QRect &)

As Qt is supposed to support high DPI features, what am I doing wrong?

NOTE below is the window code for the first situation:

    // common properties
    id: awMainForm
    objectName: "awMainForm"
    width: 602
    height: 728
    minimumWidth: 602
    minimumHeight: 728
    maximumWidth: 602
    maximumHeight: 728
    flags: (Qt.Window | Qt.FramelessWindowHint)
    visible: true

and for the second:

    // common properties
    id: awMainForm
    objectName: "awMainForm"
    width: 602
    height: 728
    minimumWidth: 602
    minimumHeight: 728
    maximumWidth: 602
    maximumHeight: 728
    flags: Qt.Window
    visible: true

jeanmilost

I finally found a solution which seems to work in my case. I added the Qt.MSWindowsFixedSizeDialogHint window flag, which seems to fix the issue.

So below is the modified code:

ApplicationWindow
{
    // common properties
    id: awMainForm
    width: 602
    height: 728
    flags: Qt.Window | Qt.FramelessWindowHint | Qt.MSWindowsFixedSizeDialogHint
    visible: true

    // form content isn't relevant
    ...
}