Added more differenciation between rgb1 and rgb255.

colors.lua

@@ -2,9 +2,19 @@
 	This is a collection of functions for performing color operations,
 	designed to work with the LÖVE game engine.
 
-	See `README_COLOR_TOOLS.md` for full documentation.
-
 	LICENSE is BEER-WARE.
+
+    # Documentation #
+
+    Supports following color formats:
+
+    - `rgb255`: The standard computer representation, with each
+      channel (red, green, blue, alpha) in the [0-255] range. Alpha
+      channel (index 4), can either be explicit or implicit (and taken
+      to be 255.)
+    - `rgb1`: As above, except channels are in the [0-1] range.
+    - `hsl`: Hue-saturation-lightness representation (does not support alpha).
+      Hue channel is in the [0-1] range, instead of the standard [0-2*pi] range.
 ]]
 
 local GAMMA = 2.2
@@ -12,11 +22,59 @@ local GAMMA_INV = 1/GAMMA
 
 local colors = {}
 
+--------------------------------------------------------------------------------
+-- Formats
+
+local function is_rgb255 (c)
+    -- Assert table with certain length
+    if type(c) ~= 'table' or #c < 3 then
+        return false
+    end
+
+    -- Check that entries are numbers
+    for i = 1, math.min(#c, 3) do
+        if type(c[i]) ~= 'number' then  return false  end
+    end
+
+    --
+    return true
+end
+
+is_rgb1 = is_rgb255
+
+local function is_hsl (c)
+    -- Assert table with certain length
+    if type(c) ~= 'table' or #c < 3 then
+        return false
+    end
+
+    -- Check that entries are numbers
+    for i = 1, math.min(#c, 3) do
+        if type(c[i]) ~= 'number' then  return false  end
+    end
+
+    --
+    return true
+end
+
 --------------------------------------------------------------------------------
 -- Conversion
 
-colors.rgb255_to_rgb1 = function (color)
+local function mult_channels (multiplier, default, color, ...)
-    return { color[1]/255, color[2]/255, color[3]/255, (color[4] or 255)/255 }
+    local r, g, b, a  =  color, ...
+    if type(color) == 'table' then
+        r, g, b, a  =  unpack(color)
+    end
+
+    return { r*multiplier, g*multiplier, b*multiplier, a and a*multiplier or default }
+end
+
+colors.rgb255_to_rgb1 = function (...)
+    return mult_channels(1/255, 1, ...)
+end
+
+colors.rgb1_to_rgb255 = function (...)
+    return mult_channels(255, 255, ...)
 end
 
 colors.rgb_to_hsl = function (color)