7

I have a Qt Widgets application using Qt styleSheet for the app look and feel. We want to add support for high-DPI displays, as on these, the app looks very small. The first step was thus to call:

QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

This does most of the job and the app window is big enough. The only remaining issue is the resolution of the images used in style sheet.

Say that we have:

QCheckBox::indicator::unchecked {
    image: url(:/res/checkbox_off.png);
}
MainWindow QFrame {
    background-image: url(:/res/background.png);
}

When using high DPI scaling, these images get upscaled accordingly which is a problem. For high DPI, I would prefer to use higher resolution images to make them look as crisp as possible.

As expected, a naive approach of simply providing the images in higher resolution does not work - it makes images and controls twice as large (on both low and high DPI screens).

Qt documentation on QImageReader states that

The high resolution version is marked by the suffix @2x on the base name. The image read will have its device pixel ratio set to a value of 2.

However, I have provided these resources with twice the resolution, added them to qrc file, but the images displayed are still the same on device with pixel_ratio of 3.

Are there any other steps needed to make this automatic image loading work with stylesheets?

majk
  • 827
  • 5
  • 12
  • 1
    Not until DPI awareness implemented everything will be smooth and adequate in UI for high DPI. I believe this answer is applicable to your issue as well: http://stackoverflow.com/questions/37303941/qt5-6-high-dpi-support-and-opengl-openscenegraph/37304973#37304973 Qt simply is imperfect but the common divider works better. – Alexander V Jun 20 '16 at 21:33
  • Seems you faced with this Qt bug: https://bugreports.qt.io/browse/QTBUG-36825 – ramzes2 Dec 27 '16 at 08:10
  • We use SVGs and it looks nice. You could also try upgrading your Qt version, they made various improvements regarding HDPI screens. – SteakOverflow Feb 24 '17 at 14:07

0 Answers0