branch: externals/ement
commit 298a902e07443579db5aefc280d85361614cc832
Author: Adam Porter <a...@alphapapa.net>
Commit: Adam Porter <a...@alphapapa.net>
Fix: Color-related compatibility with Emacs 27
Copy (color-luminance-dark-limit) and (color-dark-p) from Emacs 28.
Fixes #99. Thanks to Phil Sainty (@phil-s).
Reported-by: Phil Sainty <psai...@orcon.net.nz>
Suggested-by: Phil Sainty <psai...@orcon.net.nz>
---
README.org | 1 +
ement-lib.el | 45 ++++++++++++++++++++++++++++++++++++++++++++-
ement-notify.el | 2 +-
ement-room.el | 2 +-
4 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/README.org b/README.org
index 44f746a70f..a1d4674867 100644
--- a/README.org
+++ b/README.org
@@ -303,6 +303,7 @@ Note that, while ~matrix-client~ remains usable, and
probably will for some time
+ Command ~ement-describe-room~ for rooms without topics.
+ Improve insertion of old messages around existing timestamp headers.
+ Reduce D-Bus notification system check timeout to 2 seconds (from the
default of 25).
++ Compatibility with Emacs 27.
** 0.2.1
diff --git a/ement-lib.el b/ement-lib.el
index dfcb433114..31d5bb48e8 100644
--- a/ement-lib.el
+++ b/ement-lib.el
@@ -61,6 +61,49 @@
(defvar ement-room-prism-color-adjustment)
(defvar ement-room-prism-minimum-contrast)
+;;;; Compatibility
+
+;; These workarounds should be removed when they aren't needed.
+
+;;;;; Emacs 28 color features.
+
+;; Copied from Emacs 28. See
<https://github.com/alphapapa/ement.el/issues/99>.
+
+;; FIXME: Remove this workaround when possible.
+
+(eval-and-compile
+ (unless (boundp 'color-luminance-dark-limit)
+ (defconst ement--color-luminance-dark-limit 0.325
+ "The relative luminance below which a color is considered 'dark'.
+A 'dark' color in this sense provides better contrast with white
+than with black; see `color-dark-p'.
+This value was determined experimentally.")))
+
+(defalias 'ement--color-dark-p
+ (if (fboundp 'color-dark-p)
+ 'color-dark-p
+ (lambda (rgb)
+ "Whether RGB is more readable against white than black.
+RGB is a 3-element list (R G B), each component in the range [0,1].
+This predicate can be used both for determining a suitable (black or white)
+contrast colour with RGB as background and as foreground."
+ (unless (<= 0 (apply #'min rgb) (apply #'max rgb) 1)
+ (error "RGB components %S not in [0,1]" rgb))
+ ;; Compute the relative luminance after gamma-correcting (assuming sRGB),
+ ;; and compare to a cut-off value determined experimentally.
+ ;; See https://en.wikipedia.org/wiki/Relative_luminance for details.
+ (let* ((sr (nth 0 rgb))
+ (sg (nth 1 rgb))
+ (sb (nth 2 rgb))
+ ;; Gamma-correct the RGB components to linear values.
+ ;; Use the power 2.2 as an approximation to sRGB gamma;
+ ;; it should be good enough for the purpose of this function.
+ (r (expt sr 2.2))
+ (g (expt sg 2.2))
+ (b (expt sb 2.2))
+ (y (+ (* r 0.2126) (* g 0.7152) (* b 0.0722))))
+ (< y ement--color-luminance-dark-limit)))))
+
;;;; Functions
;;;;; Commands
@@ -556,7 +599,7 @@ avatars, etc."
"white"))
(_
;; The `contrast-with` color is
usable: test it.
- (if (color-dark-p
(color-name-to-rgb contrast-with))
+ (if (ement--color-dark-p
(color-name-to-rgb contrast-with))
"white" "black")))))))
(apply #'color-rgb-to-hex (append color-rgb (list 2))))))
diff --git a/ement-notify.el b/ement-notify.el
index b73eb605b9..d929d0022f 100644
--- a/ement-notify.el
+++ b/ement-notify.el
@@ -325,7 +325,7 @@ If ROOM has no existing buffer, do nothing."
(let ((color (color-desaturate-name
(ement--prism-color (ement-room-id room)
:contrast-with (face-foreground 'default))
50)))
- (if (color-dark-p (color-name-to-rgb (face-background 'default)))
+ (if (ement--color-dark-p (color-name-to-rgb (face-background
'default)))
(color-darken-name color 25)
(color-lighten-name color 25))))))
diff --git a/ement-room.el b/ement-room.el
index 3a65731d0f..30f025d6f9 100644
--- a/ement-room.el
+++ b/ement-room.el
@@ -895,7 +895,7 @@ spec) without requiring all events to use the same margin
width."
(setf (ement-user-message-color sender)
(let ((message-color
(color-desaturate-name (ement--user-color sender)
ement-room-prism-message-desaturation)))
- (if (color-dark-p
(color-name-to-rgb (face-background 'default)))
+ (if (ement--color-dark-p
(color-name-to-rgb (face-background 'default)))
(color-lighten-name
message-color ement-room-prism-message-lightening)
(color-darken-name message-color
ement-room-prism-message-lightening))))))))
(redacted-face (when (or local-redacted-by unsigned-redacted-by)
