Custom cursors on X11 don't respect high DPI scaling

The example code below creates a 32-logical-pixels-tall window and sets a custom 2x-scaled cursor. The cursor size should match the window height exactly, and the hotspot should lay at the center of the cursor.

#include <QWindow>
#include <QGuiApplication>int main(int ac, char *av[])
{
    QGuiApplication app(ac,av);
    QWindow w;
    QImage image(64, 64, QImage::Format_ARGB32);
    image.fill(0);
    auto pixels = (uint32_t*)image.bits();
    for(int i=0;i<64;i++) {
        pixels[i*64+i] = 0xffff0000;
        pixels[i*64+63-i] = 0xff0000ff;
    }
    auto pixmap = QPixmap::fromImage(image);
    pixmap.setDevicePixelRatio(2);
    w.setCursor(QCursor(pixmap, 16, 16));
    w.resize(200, 32);
    w.show();
    app.exec();
    return 0;
}

This works correctly on Windows and Mac. On X11 however, two issues are apparent:

1. The pixmap's devicePixelRatio is ignored and the cursor is 64x64 even on low-dpi displays. This also causes the hotspot position to be applied incorrectly
2. The display scaling factor is ignored and the cursor size doesn't match the window size on high-dpi displays (except for exact 2x scaling where the two issues cancel out).