dimmer.el

Visually highlight the selected buffer.

Description

This package provides a minor mode that indicates which buffer is currently active by dimming the faces in the other buffers. It does this nondestructively, and computes the dimmed faces dynamically such that your overall color scheme is shown in a muted form without requiring you to define what is a "dim" version of every face.

dimmer.el can be configured to adjust foreground colors (default), background colors, or both.

Demo

(click thumbnail for higher quality)

Usage Example

 (require 'dimmer)
 (dimmer-configure-which-key)
 (dimmer-configure-helm)
 (dimmer-mode t)

Configuration

By default dimmer excludes the minibuffer and echo areas from consideration, so that most packages that use the minibuffer for interaction will behave as users expect.

dimmer-configure-helm is a convenience function for helm users that further modifies the customizations so helm buffers are not dimmed.
dimmer-configure-hydra is a convenience function for hydra users that modifies the customizations so "LV" buffers are not dimmed.
dimmer-configure-which-key is a convenience function for which-key users that modifies the customizations so which-key popups are not dimmed.

Please submit pull requests with configurations for other packages!

Customization

dimmer-adjustment-mode controls what aspect of the color scheme is adjusted when dimming. Choices are :foreground (default), :background, or :both.
dimmer-fraction controls the degree to which buffers are dimmed. Range is 0.0 - 1.0, and default is 0.20. Increase value if you like the other buffers to be more dim.
dimmer-buffer-exclusion-regexps can be used to specify buffers that should never be dimmed. If the buffer name matches any regexp in this list then dimmer.el will not dim that buffer. Note, this variable replaces dimmer-exclusion-regexp and dimmer-exclusion-regexp-list, which are now obsolete.
dimmer-buffer-exclusion-predicates can be used to specify buffers that should never be dimmed. If any predicate function in this list returns true for the buffer then dimmer.el will not dim that buffer.
dimmer-prevent-dimming-predicates can be used to prevent dimmer from altering the dimmed buffer list. This can be used to detect cases where a package pops up a window temporarily, and we don't want the dimming to change. If any function in this list returns a non-nil value, dimming state will not be changed. (Note, this variable replaces dimmer-exclusion-predicates which was introduced in snapshots prior to release 0.4.0 of this package.)
dimmer-watch-frame-focus-events controls whether dimmer will dim all buffers when Emacs no longer has focus in the windowing system. This is enabled by default. Some users may prefer to set this to nil, and have the dimmed / not dimmed buffers stay as-is even when Emacs doesn't have focus.
dimmer-use-colorspace allows you to specify what color space the dimming calculation is performed in. In the majority of cases you won't need to touch this setting. See Troubleshooting below ("dimmed colors look wrong") for an example where you might need to set this.

How Colors Are Adjusted

This package chooses a "dimmed" version of the foreground (and optionaly the background color) of each of your defined faces. It does this by shifting everything by a fraction toward the default face.

If your default foreground is "white" then the background colors of each of your faces will be shifted toward "white" when dimmed.

Similarly, if your default background is a dark blue, then the foreground colors of your faces will be shifted "darker" and "more blue" when buffers are dimmed.

Troubleshooting

Windows aren't dimming when I switch from one to another.

Do you have different buffers in those windows? It's very common to test this package by installing it, launching emacs, and splitting *scratch* into two windows and then toggling between the two windows. Users may be surprised to find nothing happens.

Why not? This module makes use of the face-remap-* APIs in Emacs, and these APIs work on buffers rather than windows. If you have multiple windows displaying the same buffer they will dim or undim together. Which means, until and unless you switch the other window to a new buffer, you won't see the dimming effect.

If/when Emacs offers the controls I need to do window-specific face remaps, I'll gladly put this feature in. In the meantime, my configuration combines this package with global-hl-line-mode so I still have a visual cue which window is active.

It doesn't dim enough. I can barely see it.

Users of light themes may need to increase dimmer-fraction in order to see the effect. I may someday increase the default.

Dimmed colors sometimes look "wrong". They're getting shifted to the wrong hue.

Try customizing dimmer-use-colorspace and choose RGB instead. Customize this variable and read the documentation in the customization screens for more background on this issue.

License

Distributed under the GNU General Public License, Version 3

hkjels / dimmer.el