KWin Rules

Overview

KWin allows the end-user to define rules to alter the behavior of an application's windows.

For example, when an application is started, it can be forced to always run on Virtual Desktop #2. Or a defect in an application can be worked-around by using a rule to, say, always force the window on top of all others.

This page will define the different settings and the attributes. For the impatient folks, working examples will be listed. Whenever possible, screen shots will be used to show example settings.

Ktip.png
Tip
Panels can also be affected.


KWin Rule Editor

Kwin-rules-ordering.png

Invoking the Editor

There are several ways one can invoke the Rules editor. Below are a couple:

  • Right-click on the title-bar of any window, choose Configure Window Behavior ... and in the Configure window, select Window Rules or
  • Configure Desktop -> Window Behavior -> Window Rules

Anatomy

Kwin-rule-editor.png

The editor is composed of four tabs:

  1. Window matching
  2. Size & Position
  3. Arrangement & Access
  4. Appearance & Fixes

As the name implies, Window matching is used to specify criteria to match one or more windows. The other three tabs are used to alter the characteristics of the matching windows.

Rules

Evaluation

KWin evaluates the rules when an application starts and after editing rules. Any matching rule's attribute(s) override the application's corresponding attribute(s).

Precedence

In the Window Rules window, the rules are listed in the order in which they are processed.

The rule at the top of the list is processed first, followed by the next rule until the end of the list is reached.

Conflicts

In the event two rules match a window and affect the same attribute, the first rule in the list takes precedence.

Window Matching

Kwin-window-matching.png

The Window Matching tab provides a series of matching-criteria fields used to identify application windows:

  • Window class (application) - match this window and all its children windows.
    • and Match whole window class
  • Window role - restrict the match to the function of the window (e.g. a main window, a chat window, etc.)
  • Window types - restrict the match to the type of window: Normal Window, Dialog Window, etc.
  • Window title - restrict the match to the title of the window.
  • Machine (hostname) - restrict the match to the host name associated with the window.
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Tip
While it's possible to manually enter the above information, the preferred method is to use the Detect Window Properties button.


For each field, the following operators can be applied against the field value:

  • Unimportant
  • Exact Match
  • Substring Match
  • Regular Expression - Qt's regular expressions are implemented. For additional information, web search qt regex nokia.
Detect Window Properties
Kwin-detect-window.png

The Detect Window Properties function simplifies the process of entering the matching-criteria.

  1. For the application you'd like to create a rule, start the application.
  2. Next, in the Window matching tab, set the number of seconds of delay before the Detect Window Properties function starts. The default is zero seconds.
  3. Click on Detect Window Properties and
  4. When the mouse-cursor turns to cross-hairs, place it inside the application window and left-click.
  5. A new window is presented with information about the selected window:
    • Class
    • Role
    • Type
    • Title
    • Machine (hostname)


Click the OK button to back-fill the Window Matching criteria.

By using a combination of the information, you can tailor whether a rule applies to an entire application (by Class) or a to a specific window Type within the Class - say a Toolbar.

Window Attributes

Kwin-window-attributes.png

The attributes which can be set are grouped in three tabs:

  1. Size & Position
  2. Arrangement & Access
  3. Appearance & Fixes

Each attribute has additional settings which determine when they're applied and depending on the attribute, there may be an additional argument.

Attributes

Ktip.png
Tip
Using Detect Window Properties back-fills values for attributes. For example the height and width arguments of the Size attribute is set to the height and width of the detected window.
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Tip
Yes/No arguments are used to toggle attributes. For example, if a window's default behavior is to start horizontally maximized and you wish to disable this behavior, specify No as the argument to Maximized horizontally, on the other hand if you wish to force a window to start horizontally maximized, specify Yes.


Size & Position
Position
Position the window's upper left corner at the specified x,y coordinate.
Ktip.png
Tip
KWin's origin, (0,0), is the upper left.
Size
The width and height of the window.
Maximized horizontally, Maximized vertically, Fullscreen
These attributes are used to toggle the maximum horizontal/minimum horizontal/full-screen window attribute.
Desktop
Place the window on the designated (Virtual) Desktop Use 'All Desktops to place the window on all Virtual Desktops.
Minimized, Shaded
Toggle the Minimize and Shading window attribute. For example, a window can be started Minimized or if it is started Minimized, it can be forced to not.
Ktip.png
Tip
Maximized attribute is emulated by using both Maximized horizontally and Maximized vertically.
Initial placement
Override the global window placement strategy.
Ignore requested geometry
Toggle whether to accept or ignore the window's requested geometry and ignore the global placement strategy.
Minimum size, Maximum size
The minimum and maximum size allowed for the window.
Obey geometry restrictions
Toggle whether to adhere to the window's requested aspect ratio.
Arrangement & Access
Keep above
Def
Keep below
Def
Autogroup with identical
Def
Autogroup in foreground
Def
Autogruop by ID
Def
Tiling
Def
Skip taskbar
Def
Skip pager
Def
Skip switcher
Def
Shortcut
Def
Appearance & Fixes
Not titlebar and frame
Def
Active opacity
Def
Inactive opacity
Def
Moving/resizing
Def
Focus stealing prevention
Def
Accept focus
Def
Ignore global shortcuts
Def

Disposition

Do Not Affect
Definition
Apply Initially
Definition
Remember
Def
Force
Def
Apply Now
Def
Force Temporarily
Def

Examples

Force a Window on a Desktop

Force a Window on all Desktops

Suppress a Window showing on Pager

Force a Window to the Top

Good for knotes

Multiple Rules per Application

e.g. Thunderbird on one desktop and composition window on any


This page was last edited on 22 January 2021, at 22:44. Content is available under Creative Commons License SA 4.0 unless otherwise noted.