How to change background image of Dolphin file browser from default white background?

Question

I am using Kubuntu 16.10 which has Dolphin file Manager having default white background. I want to give a custom image as background as there in the desktop.

Answer 1

Qt Style Sheets

http://doc.qt.io/qt-5/stylesheet.html :

Qt Style Sheets are a powerful mechanism that allows you to customize the appearance of widgets...

More:

• Qt Style Sheets Examples: http://doc.qt.io/qt-5/stylesheet-examples.html
• Qt Style Sheets Reference: http://doc.qt.io/qt-5/stylesheet-reference.html

QSS & Dolphin background image

Older from the KDE Forums - How to set a pattern (image) as a wallpaper on Dolphin?: https://forum.kde.org/viewtopic.php?f=17&t=94717

and more:

• Deviantart: http://samuaz.deviantart.com/art/Kde-GaiaSnow-update-4-373661315 -> http://pastebin.com/wEnndQPw
• [SOLVED] Scaled background image using stylesheet: https://forum.qt.io/topic/40151/solved-scaled-background-image-using-stylesheet/2

Example

Making backStyle.qss:

DolphinViewContainer > DolphinView > QAbstractScrollArea {
      background-color: transparent;
      border-image: url('background.png') 0 0 0 0 stretch stretch;
}

and starting the Dolphin with the command:

dolphin -stylesheet /path/to/myqss/backStyle.qss 

The result:

Note

The Dolphin is painting every other line with the alternate background color in the details view mode:

You could change the color but you can't edit the transparency without rebuild of the Dolphin.

Changing the .../src/kitemviews/kitemlistwidget.cpp line 118 from:

const QColor backgroundColor = m_styleOption.palette.color(QPalette::AlternateBase);

to

const QColor backgroundColor = QColor(0, 0, 0, 20);

About Qt colors: http://doc.qt.io/qt-5/qcolor.html#QColor-2

After rebuild:

Answer 2

For quite a while I wanted to make the background of the file area in Dolphin Transparent or Translucent - like the Folder View Widget that I could have on my desktop. Over the years I messed with different ideas and had a little success, but not the look I wanted to go with my translucent panels and window decorations.

This week I finally achieved a completely translucent 'Dolphin'. The Bright Red buttons and selections will not be everybody's choise - but they can all be toned down. The 'Blur Effect' is enabled using GL3.1 in compositing settings in Kubuntu 18.10, but the translucency works and can be adjusted without the blurring using Xrender and in earlier versions of Kubuntu.

This was achieved very simply using the Kvantum theming engine and Kvantum Theme Manager.

While this is not changing the background image in Dolphin, quite a few of us found this topic whilst trying to make a translucent background in Dolphin - so I hope this helps.