log: respect the NO_COLOR environment variable

http://no-color.org/

2 files changed, 9 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 210d363..f2290cc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@
 
 * Nanosvg updated to 93ce879dc4c04a3ef1758428ec80083c38610b1f
 * JPEG XL support ([#14][14])
+* Log output now respects the [`NO_COLOR`](http://no-color.org/)
+  environment variable.
 
 [14]: https://codeberg.org/dnkl/wbg/pulls/14
 
diff --git a/log.c b/log.c
index c5d9093..950e641 100644
--- a/log.c
+++ b/log.c
@@ -30,7 +30,13 @@ log_init(enum log_colorize _colorize, bool _do_syslog,
         [LOG_CLASS_DEBUG] = LOG_DEBUG,
     };
 
-    colorize = _colorize == LOG_COLORIZE_NEVER ? false : _colorize == LOG_COLORIZE_ALWAYS ? true : isatty(STDERR_FILENO);
+    /* Don't use colors if NO_COLOR is defined and not empty */
+    const char *no_color_str = getenv("NO_COLOR");
+    const bool no_color = no_color_str != NULL && no_color_str[0] != '\0';
+
+    colorize = _colorize == LOG_COLORIZE_NEVER
+        ? false : _colorize == LOG_COLORIZE_ALWAYS
+            ? true : !no_color && isatty(STDERR_FILENO);
     do_syslog = _do_syslog;
 
     if (do_syslog) {