* Fixed colour conversion routines so that they work with ARGB too.

cucul/colour.c

@@ -29,24 +29,64 @@ static const uint16_t ansitab[16] =
     0xf444, 0xf44f, 0xf4f4, 0xf4ff, 0xff44, 0xff4f, 0xfff4, 0xffff,
 };
 
-/* FIXME: could this be inlined? */
+static uint8_t nearest_ansi(uint16_t argb16, uint8_t def)
+{
+    unsigned int i, best, dist;
+
+    if(argb16 < CUCUL_COLOR_DEFAULT)
+        return argb16;
+
+    if(argb16 == CUCUL_COLOR_DEFAULT || argb16 == CUCUL_COLOR_TRANSPARENT)
+        return def;
+
+    if(argb16 < 0x5fff) /* too transparent, return default colour */
+        return def;
+
+    dist = 0xffff;
+    for(i = 0; i < 16; i++)
+    {
+        unsigned int d = 0;
+        int a, b;
+
+        a = (ansitab[i] >> 8) & 0xf;
+        b = (argb16 >> 8) & 0xf;
+        d += (a - b) * (a - b);
+
+        a = (ansitab[i] >> 4) & 0xf;
+        b = (argb16 >> 4) & 0xf;
+        d += (a - b) * (a - b);
+
+        a = ansitab[i] & 0xf;
+        b = argb16 & 0xf;
+        d += (a - b) * (a - b);
+
+        if(d < dist)
+        {
+            dist = d;
+            best = i;
+        }
+    }
+
+    return best;
+}
 
 uint8_t _cucul_argb32_to_ansi8(uint32_t c)
 {
-    /* FIXME: we need nearest colour handling for non-ANSI */
-    return (c & 0x0000000f) | ((c & 0x000f0000) >> 12);
+    uint16_t fg = c & 0xffff;
+    uint16_t bg = c >> 16;
+
+    return nearest_ansi(fg, CUCUL_COLOR_LIGHTGRAY)
+            | (nearest_ansi(bg, CUCUL_COLOR_BLACK) << 4);
 }
 
 uint8_t _cucul_argb32_to_ansi4fg(uint32_t c)
 {
-    /* FIXME: we need nearest colour handling for non-ANSI */
-    return c & 0x0000000f;
+    return nearest_ansi(c & 0xffff, CUCUL_COLOR_LIGHTGRAY);
 }
 
 uint8_t _cucul_argb32_to_ansi4bg(uint32_t c)
 {
-    /* FIXME: we need nearest colour handling for non-ANSI */
-    return (c & 0x000f0000) >> 16;
+    return nearest_ansi(c >> 16, CUCUL_COLOR_BLACK);
 }
 
 void _cucul_argb32_to_argb4(uint32_t c, uint8_t argb[8])
@@ -54,11 +94,19 @@ void _cucul_argb32_to_argb4(uint32_t c, uint8_t argb[8])
     uint16_t fg = c & 0xffff;
     uint16_t bg = c >> 16;
 
-    if(fg < 0x0016)
+    if(fg < CUCUL_COLOR_DEFAULT)
         fg = ansitab[fg];
+    else if(fg == CUCUL_COLOR_DEFAULT)
+        fg = ansitab[CUCUL_COLOR_LIGHTGRAY];
+    else if(fg == CUCUL_COLOR_TRANSPARENT)
+        fg = 0x0fff;
 
-    if(bg < 0x0016)
+    if(bg < CUCUL_COLOR_DEFAULT)
         bg = ansitab[bg];
+    else if(bg == CUCUL_COLOR_DEFAULT)
+        bg = ansitab[CUCUL_COLOR_BLACK];
+    else if(bg == CUCUL_COLOR_TRANSPARENT)
+        bg = 0x0fff;
 
     argb[0] = bg >> 12;
     argb[1] = (bg >> 8) & 0xf;