Tags: patch

Hello everyone,

CC: Eric M. Ludlam (author of pulse.el) and Protesilaos Stavrou (author
of pulsar.el).

I wanted to use pulse.el without the pulse effect, that is, I have set
the variable pulse-iterations to 1, and I was expecting the pulse
library to simply highlight a region or line for the duration specified
in the variable pulse-delay with the face pulse-highlight-start-face.

It works, except that the face used is not pulse-highlight-start-face.

To reproduce in emacs -Q:
(require 'pulse)
(setopt pulse-iterations 1)
(setopt pulse-delay 5)
(set-face-background 'pulse-highlight-start-face "#ff0000")
(pulse-momentary-highlight-one-line)

Note that the color used by pulse is not pulse-highlight-start-face
(pure red).

If I understand correctly, this behavior comes from the function
pulse-momentary-highlight-overlay. The function
pulse-momentary-highlight-overlay sets an overlay using the face
pulse-highlight-face (reseted to pulse-highlight-start-face by default,
that is, if the argument of pulse-momentary-highlight-overlay is nil),
the function then immediatly starts the pulsation effect. The list of
colors for the pulsation effect is generated by the function
color-gradient, but the documentation of color-gradient says about its
output: "It does not include the START and STOP color in the resulting
list". Thus the first visible color is the first color of the list
returned by color-gradient which is different that the starting face
(pulse-highlight-start-face by default).

A simple solution would be to add the starting color
(pulse-highlight-start-face by default) at the beginning of the list of
colors used for the pulsation effect in
pulse-momentary-highlight-overlay. Please find attached to this mail a
patch for pulse.el which does this modification.

All the best,
Gautier

------------------------------------------------------------------------
In GNU Emacs 31.0.50 (build 61, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.18.0, Xaw3d scroll bars) of 2024-08-08 built on
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Repository revision: 8b662047074f7413c280c9092d1c39763f8b0e5b
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