NCurses: better support for 256 color terminals that cannot change colors

1 files changed, 68 insertions, 13 deletions

diff --git a/src/ncurses.cc b/src/ncurses.cc
index cd5bfde4..eba9a911 100644
--- a/src/ncurses.cc
+++ b/src/ncurses.cc
@@ -81,29 +81,84 @@ static int nc_color(Color color)
     else
     {
         kak_assert(color.color == Colors::RGB);
-        // project to closest color.
-        struct BuiltinColor { int id; unsigned char r, g, b; };
-        static constexpr BuiltinColor builtins[] = {
-            { COLOR_BLACK,   0,   0,   0 },
-            { COLOR_RED,     255, 0,   0 },
-            { COLOR_GREEN,   0,   255, 0 },
-            { COLOR_YELLOW,  255, 255, 0 },
-            { COLOR_BLUE,    0,   0,   255 },
-            { COLOR_MAGENTA, 255, 0,   255 },
-            { COLOR_CYAN,    0,   255, 255 },
-            { COLOR_WHITE,   255, 255, 255 }
+        static const struct { unsigned char r, g, b; } builtin_colors[] = {
+            {0x00,0x00,0x00}, {0x80,0x00,0x00}, {0x00,0x80,0x00}, {0x80,0x80,0x00},
+            {0x00,0x00,0x80}, {0x80,0x00,0x80}, {0x00,0x80,0x80}, {0xc0,0xc0,0xc0},
+            {0x80,0x80,0x80}, {0xff,0x00,0x00}, {0x00,0xff,0x00}, {0xff,0xff,0x00},
+            {0x00,0x00,0xff}, {0xff,0x00,0xff}, {0x00,0xff,0xff}, {0xff,0xff,0xff},
+            {0x00,0x00,0x00}, {0x00,0x00,0x5f}, {0x00,0x00,0x87}, {0x00,0x00,0xaf},
+            {0x00,0x00,0xd7}, {0x00,0x00,0xff}, {0x00,0x5f,0x00}, {0x00,0x5f,0x5f},
+            {0x00,0x5f,0x87}, {0x00,0x5f,0xaf}, {0x00,0x5f,0xd7}, {0x00,0x5f,0xff},
+            {0x00,0x87,0x00}, {0x00,0x87,0x5f}, {0x00,0x87,0x87}, {0x00,0x87,0xaf},
+            {0x00,0x87,0xd7}, {0x00,0x87,0xff}, {0x00,0xaf,0x00}, {0x00,0xaf,0x5f},
+            {0x00,0xaf,0x87}, {0x00,0xaf,0xaf}, {0x00,0xaf,0xd7}, {0x00,0xaf,0xff},
+            {0x00,0xd7,0x00}, {0x00,0xd7,0x5f}, {0x00,0xd7,0x87}, {0x00,0xd7,0xaf},
+            {0x00,0xd7,0xd7}, {0x00,0xd7,0xff}, {0x00,0xff,0x00}, {0x00,0xff,0x5f},
+            {0x00,0xff,0x87}, {0x00,0xff,0xaf}, {0x00,0xff,0xd7}, {0x00,0xff,0xff},
+            {0x5f,0x00,0x00}, {0x5f,0x00,0x5f}, {0x5f,0x00,0x87}, {0x5f,0x00,0xaf},
+            {0x5f,0x00,0xd7}, {0x5f,0x00,0xff}, {0x5f,0x5f,0x00}, {0x5f,0x5f,0x5f},
+            {0x5f,0x5f,0x87}, {0x5f,0x5f,0xaf}, {0x5f,0x5f,0xd7}, {0x5f,0x5f,0xff},
+            {0x5f,0x87,0x00}, {0x5f,0x87,0x5f}, {0x5f,0x87,0x87}, {0x5f,0x87,0xaf},
+            {0x5f,0x87,0xd7}, {0x5f,0x87,0xff}, {0x5f,0xaf,0x00}, {0x5f,0xaf,0x5f},
+            {0x5f,0xaf,0x87}, {0x5f,0xaf,0xaf}, {0x5f,0xaf,0xd7}, {0x5f,0xaf,0xff},
+            {0x5f,0xd7,0x00}, {0x5f,0xd7,0x5f}, {0x5f,0xd7,0x87}, {0x5f,0xd7,0xaf},
+            {0x5f,0xd7,0xd7}, {0x5f,0xd7,0xff}, {0x5f,0xff,0x00}, {0x5f,0xff,0x5f},
+            {0x5f,0xff,0x87}, {0x5f,0xff,0xaf}, {0x5f,0xff,0xd7}, {0x5f,0xff,0xff},
+            {0x87,0x00,0x00}, {0x87,0x00,0x5f}, {0x87,0x00,0x87}, {0x87,0x00,0xaf},
+            {0x87,0x00,0xd7}, {0x87,0x00,0xff}, {0x87,0x5f,0x00}, {0x87,0x5f,0x5f},
+            {0x87,0x5f,0x87}, {0x87,0x5f,0xaf}, {0x87,0x5f,0xd7}, {0x87,0x5f,0xff},
+            {0x87,0x87,0x00}, {0x87,0x87,0x5f}, {0x87,0x87,0x87}, {0x87,0x87,0xaf},
+            {0x87,0x87,0xd7}, {0x87,0x87,0xff}, {0x87,0xaf,0x00}, {0x87,0xaf,0x5f},
+            {0x87,0xaf,0x87}, {0x87,0xaf,0xaf}, {0x87,0xaf,0xd7}, {0x87,0xaf,0xff},
+            {0x87,0xd7,0x00}, {0x87,0xd7,0x5f}, {0x87,0xd7,0x87}, {0x87,0xd7,0xaf},
+            {0x87,0xd7,0xd7}, {0x87,0xd7,0xff}, {0x87,0xff,0x00}, {0x87,0xff,0x5f},
+            {0x87,0xff,0x87}, {0x87,0xff,0xaf}, {0x87,0xff,0xd7}, {0x87,0xff,0xff},
+            {0xaf,0x00,0x00}, {0xaf,0x00,0x5f}, {0xaf,0x00,0x87}, {0xaf,0x00,0xaf},
+            {0xaf,0x00,0xd7}, {0xaf,0x00,0xff}, {0xaf,0x5f,0x00}, {0xaf,0x5f,0x5f},
+            {0xaf,0x5f,0x87}, {0xaf,0x5f,0xaf}, {0xaf,0x5f,0xd7}, {0xaf,0x5f,0xff},
+            {0xaf,0x87,0x00}, {0xaf,0x87,0x5f}, {0xaf,0x87,0x87}, {0xaf,0x87,0xaf},
+            {0xaf,0x87,0xd7}, {0xaf,0x87,0xff}, {0xaf,0xaf,0x00}, {0xaf,0xaf,0x5f},
+            {0xaf,0xaf,0x87}, {0xaf,0xaf,0xaf}, {0xaf,0xaf,0xd7}, {0xaf,0xaf,0xff},
+            {0xaf,0xd7,0x00}, {0xaf,0xd7,0x5f}, {0xaf,0xd7,0x87}, {0xaf,0xd7,0xaf},
+            {0xaf,0xd7,0xd7}, {0xaf,0xd7,0xff}, {0xaf,0xff,0x00}, {0xaf,0xff,0x5f},
+            {0xaf,0xff,0x87}, {0xaf,0xff,0xaf}, {0xaf,0xff,0xd7}, {0xaf,0xff,0xff},
+            {0xd7,0x00,0x00}, {0xd7,0x00,0x5f}, {0xd7,0x00,0x87}, {0xd7,0x00,0xaf},
+            {0xd7,0x00,0xd7}, {0xd7,0x00,0xff}, {0xd7,0x5f,0x00}, {0xd7,0x5f,0x5f},
+            {0xd7,0x5f,0x87}, {0xd7,0x5f,0xaf}, {0xd7,0x5f,0xd7}, {0xd7,0x5f,0xff},
+            {0xd7,0x87,0x00}, {0xd7,0x87,0x5f}, {0xd7,0x87,0x87}, {0xd7,0x87,0xaf},
+            {0xd7,0x87,0xd7}, {0xd7,0x87,0xff}, {0xd7,0xaf,0x00}, {0xd7,0xaf,0x5f},
+            {0xd7,0xaf,0x87}, {0xd7,0xaf,0xaf}, {0xd7,0xaf,0xd7}, {0xd7,0xaf,0xff},
+            {0xd7,0xd7,0x00}, {0xd7,0xd7,0x5f}, {0xd7,0xd7,0x87}, {0xd7,0xd7,0xaf},
+            {0xd7,0xd7,0xd7}, {0xd7,0xd7,0xff}, {0xd7,0xff,0x00}, {0xd7,0xff,0x5f},
+            {0xd7,0xff,0x87}, {0xd7,0xff,0xaf}, {0xd7,0xff,0xd7}, {0xd7,0xff,0xff},
+            {0xff,0x00,0x00}, {0xff,0x00,0x5f}, {0xff,0x00,0x87}, {0xff,0x00,0xaf},
+            {0xff,0x00,0xd7}, {0xff,0x00,0xff}, {0xff,0x5f,0x00}, {0xff,0x5f,0x5f},
+            {0xff,0x5f,0x87}, {0xff,0x5f,0xaf}, {0xff,0x5f,0xd7}, {0xff,0x5f,0xff},
+            {0xff,0x87,0x00}, {0xff,0x87,0x5f}, {0xff,0x87,0x87}, {0xff,0x87,0xaf},
+            {0xff,0x87,0xd7}, {0xff,0x87,0xff}, {0xff,0xaf,0x00}, {0xff,0xaf,0x5f},
+            {0xff,0xaf,0x87}, {0xff,0xaf,0xaf}, {0xff,0xaf,0xd7}, {0xff,0xaf,0xff},
+            {0xff,0xd7,0x00}, {0xff,0xd7,0x5f}, {0xff,0xd7,0x87}, {0xff,0xd7,0xaf},
+            {0xff,0xd7,0xd7}, {0xff,0xd7,0xff}, {0xff,0xff,0x00}, {0xff,0xff,0x5f},
+            {0xff,0xff,0x87}, {0xff,0xff,0xaf}, {0xff,0xff,0xd7}, {0xff,0xff,0xff},
+            {0x08,0x08,0x08}, {0x12,0x12,0x12}, {0x1c,0x1c,0x1c}, {0x26,0x26,0x26},
+            {0x30,0x30,0x30}, {0x3a,0x3a,0x3a}, {0x44,0x44,0x44}, {0x4e,0x4e,0x4e},
+            {0x58,0x58,0x58}, {0x60,0x60,0x60}, {0x66,0x66,0x66}, {0x76,0x76,0x76},
+            {0x80,0x80,0x80}, {0x8a,0x8a,0x8a}, {0x94,0x94,0x94}, {0x9e,0x9e,0x9e},
+            {0xa8,0xa8,0xa8}, {0xb2,0xb2,0xb2}, {0xbc,0xbc,0xbc}, {0xc6,0xc6,0xc6},
+            {0xd0,0xd0,0xd0}, {0xda,0xda,0xda}, {0xe4,0xe4,0xe4}, {0xee,0xee,0xee},
         };
         int lowestDist = INT_MAX;
         int closestCol = -1;
-        for (auto& col : builtins)
+        for (int i = 0; i < std::min(256, COLORS); ++i)
         {
+            auto& col = builtin_colors[i];
             int dist = sq(color.r - col.r)
                      + sq(color.g - col.g)
                      + sq(color.b - col.b);
             if (dist < lowestDist)
             {
                 lowestDist = dist;
-                closestCol = col.id;
+                closestCol = i;
             }
         }
         return closestCol;