From fbd4dd97f1263eb69bbb969e22d39e921aa91c20 Mon Sep 17 00:00:00 2001
From: Alexandre Bury <alexandre.bury@gmail.com>
Date: Sat, 27 Jan 2018 18:14:37 -0800
Subject: [PATCH] Add grayscale color matching for ncurses backend

---
 src/backend/curses/mod.rs | 23 ++++++++++++++++++-----
 src/backend/curses/n.rs   |  1 +
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/src/backend/curses/mod.rs b/src/backend/curses/mod.rs
index 25be9a6..c4dfe42 100644
--- a/src/backend/curses/mod.rs
+++ b/src/backend/curses/mod.rs
@@ -34,11 +34,24 @@ fn find_closest(color: &Color) -> i16 {
         Color::Light(BaseColor::Cyan) => 14,
         Color::Light(BaseColor::White) => 15,
         Color::Rgb(r, g, b) => {
-            let r = 6 * u16::from(r) / 256;
-            let g = 6 * u16::from(g) / 256;
-            let b = 6 * u16::from(b) / 256;
-            (16 + 36 * r + 6 * g + b) as i16
+            // If r = g = b, it may be a grayscale value!
+            if r == g && g == b && r != 0 && r < 250 {
+                // (r = g = b) = 8 + 10 * n
+                // (r - 8) / 10 = n
+                //
+                let n = (r - 8) / 10;
+                (232 + n) as i16
+            } else {
+                let r = 6 * u16::from(r) / 256;
+                let g = 6 * u16::from(g) / 256;
+                let b = 6 * u16::from(b) / 256;
+                (16 + 36 * r + 6 * g + b) as i16
+            }
+        }
+        Color::RgbLowRes(r, g, b) => {
+            let a = i16::from(16 + 36 * r + 6 * g + b);
+            eprintln!("{:?} => {}", color, a);
+            a
         }
-        Color::RgbLowRes(r, g, b) => i16::from(16 + 36 * r + 6 * g + b),
     }
 }
diff --git a/src/backend/curses/n.rs b/src/backend/curses/n.rs
index 66ba074..c5c322d 100644
--- a/src/backend/curses/n.rs
+++ b/src/backend/curses/n.rs
@@ -213,6 +213,7 @@ impl backend::Backend for Concrete {
     }
 
     fn with_color<F: FnOnce()>(&self, colors: ColorPair, f: F) {
+        eprintln!("Color used: {:?}", colors);
         let current = self.current_style.get();
         if current != colors {
             self.set_colors(colors);