Merge pull request #72 from idbrii/color

Overhaul color: fix bugs, change to 0-1
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shakesoda 2022-04-21 10:47:54 -07:00 committed by GitHub
commit 4350c25d0c
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2 changed files with 249 additions and 75 deletions

View File

@ -2,6 +2,7 @@
-- @module color
local modules = (...):gsub('%.[^%.]+$', '') .. "."
local constants = require(modules .. "constants")
local utils = require(modules .. "utils")
local precond = require(modules .. "_private_precond")
local color = {}
@ -10,7 +11,7 @@ local color_mt = {}
local function new(r, g, b, a)
local c = { r, g, b, a }
c._c = c
return setmetatable(c, color)
return setmetatable(c, color_mt)
end
-- HSV utilities (adapted from http://www.cs.rit.edu/~ncs/color/t_convert.html)
@ -21,7 +22,7 @@ local function hsv_to_color(hsv)
local i
local f, q, p, t
local h, s, v
local a = hsv[4] or 255
local a = hsv[4] or 1
s = hsv[2]
v = hsv[3]
@ -29,10 +30,10 @@ local function hsv_to_color(hsv)
return new(v, v, v, a)
end
h = hsv[1] / 60
h = hsv[1] * 6 -- sector 0 to 5
i = math.floor(h)
f = h - i
f = h - i -- factorial part of h
p = v * (1-s)
q = v * (1-s*f)
t = v * (1-s*(1-f))
@ -52,7 +53,7 @@ local function color_to_hsv(c)
local r = c[1]
local g = c[2]
local b = c[3]
local a = c[4] or 255
local a = c[4] or 1
local h, s, v
local min = math.min(r, g, b)
@ -72,7 +73,12 @@ local function color_to_hsv(c)
-- r = g = b = 0 s = 0, v is undefined
s = 0
h = -1
return { h, s, v, 255 }
return { h, s, v, 1 }
end
-- Prevent division by zero.
if delta == 0 then
delta = constants.DBL_EPSILON
end
if r == max then
@ -83,10 +89,10 @@ local function color_to_hsv(c)
h = 4 + ( r - g ) / delta -- magenta/cyan
end
h = h * 60 -- degrees
h = h / 6 -- normalize from segment 0..5
if h < 0 then
h = h + 360
h = h + 1
end
return { h, s, v, a }
@ -94,12 +100,12 @@ end
--- The public constructor.
-- @param x Can be of three types: </br>
-- number red component 0-255
-- number red component 0-1
-- table {r, g, b, a}
-- nil for {0,0,0,0}
-- @tparam number g Green component 0-255
-- @tparam number b Blue component 0-255
-- @tparam number a Alpha component 0-255
-- @tparam number g Green component 0-1
-- @tparam number b Blue component 0-1
-- @tparam number a Alpha component 0-1
-- @treturn color out
function color.new(r, g, b, a)
-- number, number, number, number
@ -126,17 +132,17 @@ function color.new(r, g, b, a)
end
--- Convert hue,saturation,value table to color object.
-- @tparam table hsva {hue 0-359, saturation 0-1, value 0-1, alpha 0-255}
-- @tparam table hsva {hue 0-1, saturation 0-1, value 0-1, alpha 0-1}
-- @treturn color out
color.hsv_to_color_table = hsv_to_color
--- Convert color to hue,saturation,value table
-- @tparam color in
-- @treturn table hsva {hue 0-359, saturation 0-1, value 0-1, alpha 0-255}
-- @treturn table hsva {hue 0-1, saturation 0-1, value 0-1, alpha 0-1}
color.color_to_hsv_table = color_to_hsv
--- Convert hue,saturation,value to color object.
-- @tparam number h hue 0-359
-- @tparam number h hue 0-1
-- @tparam number s saturation 0-1
-- @tparam number v value 0-1
-- @treturn color out
@ -145,10 +151,10 @@ function color.from_hsv(h, s, v)
end
--- Convert hue,saturation,value to color object.
-- @tparam number h hue 0-359
-- @tparam number h hue 0-1
-- @tparam number s saturation 0-1
-- @tparam number v value 0-1
-- @tparam number a alpha 0-255
-- @tparam number a alpha 0-1
-- @treturn color out
function color.from_hsva(h, s, v, a)
return hsv_to_color { h, s, v, a }
@ -158,35 +164,60 @@ end
-- @tparam color to invert
-- @treturn color out
function color.invert(c)
return new(255 - c[1], 255 - c[2], 255 - c[3], c[4])
return new(1 - c[1], 1 - c[2], 1 - c[3], c[4])
end
--- Lighten a color by a component-wise fixed amount (alpha unchanged)
-- @tparam color to lighten
-- @tparam number amount to increase each component by, 0-255 scale
-- @tparam number amount to increase each component by, 0-1 scale
-- @treturn color out
function color.lighten(c, v)
return new(
utils.clamp(c[1] + v * 255, 0, 255),
utils.clamp(c[2] + v * 255, 0, 255),
utils.clamp(c[3] + v * 255, 0, 255),
utils.clamp(c[1] + v, 0, 1),
utils.clamp(c[2] + v, 0, 1),
utils.clamp(c[3] + v, 0, 1),
c[4]
)
end
--- Interpolate between two colors.
-- @tparam color at start
-- @tparam color at end
-- @tparam number s in 0-1 progress between the two colors
-- @treturn color out
function color.lerp(a, b, s)
return a + s * (b - a)
end
--- Unpack a color into individual components in 0-1.
-- @tparam color to unpack
-- @treturn number r in 0-1
-- @treturn number g in 0-1
-- @treturn number b in 0-1
-- @treturn number a in 0-1
function color.unpack(c)
return c[1], c[2], c[3], c[4]
end
--- Unpack a color into individual components in 0-255.
-- @tparam color to unpack
-- @treturn number r in 0-255
-- @treturn number g in 0-255
-- @treturn number b in 0-255
-- @treturn number a in 0-255
function color.as_255(c)
return c[1] * 255, c[2] * 255, c[3] * 255, c[4] * 255
end
--- Darken a color by a component-wise fixed amount (alpha unchanged)
-- @tparam color to darken
-- @tparam number amount to decrease each component by, 0-255 scale
-- @tparam number amount to decrease each component by, 0-1 scale
-- @treturn color out
function color.darken(c, v)
return new(
utils.clamp(c[1] - v * 255, 0, 255),
utils.clamp(c[2] - v * 255, 0, 255),
utils.clamp(c[3] - v * 255, 0, 255),
utils.clamp(c[1] - v, 0, 1),
utils.clamp(c[2] - v, 0, 1),
utils.clamp(c[3] - v, 0, 1),
c[4]
)
end
@ -207,7 +238,7 @@ end
-- directly set alpha channel
-- @tparam color to alter
-- @tparam number new alpha 0-255
-- @tparam number new alpha 0-1
-- @treturn color out
function color.alpha(c, v)
local t = color.new()
@ -215,7 +246,7 @@ function color.alpha(c, v)
t[i] = c[i]
end
t[4] = v * 255
t[4] = v
return t
end
@ -235,17 +266,17 @@ end
--- Set a color's hue (saturation, value, alpha unchanged)
-- @tparam color to alter
-- @tparam hue to set 0-359
-- @tparam hue to set 0-1
-- @treturn color out
function color.hue(col, hue)
local c = color_to_hsv(col)
c[1] = (hue + 360) % 360
c[1] = (hue + 1) % 1
return hsv_to_color(c)
end
--- Set a color's saturation (hue, value, alpha unchanged)
-- @tparam color to alter
-- @tparam hue to set 0-359
-- @tparam saturation to set 0-1
-- @treturn color out
function color.saturation(col, percent)
local c = color_to_hsv(col)
@ -255,7 +286,7 @@ end
--- Set a color's value (saturation, hue, alpha unchanged)
-- @tparam color to alter
-- @tparam hue to set 0-359
-- @tparam value to set 0-1
-- @treturn color out
function color.value(col, percent)
local c = color_to_hsv(col)
@ -263,7 +294,7 @@ function color.value(col, percent)
return hsv_to_color(c)
end
-- http://en.wikipedia.org/wiki/SRGB#The_reverse_transformation
-- https://en.wikipedia.org/wiki/SRGB#From_sRGB_to_CIE_XYZ
function color.gamma_to_linear(r, g, b, a)
local function convert(c)
if c > 1.0 then
@ -280,17 +311,17 @@ function color.gamma_to_linear(r, g, b, a)
if type(r) == "table" then
local c = {}
for i = 1, 3 do
c[i] = convert(r[i] / 255) * 255
c[i] = convert(r[i])
end
c[4] = convert(r[4] / 255) * 255
c[4] = r[4]
return c
else
return convert(r / 255) * 255, convert(g / 255) * 255, convert(b / 255) * 255, a or 255
return convert(r), convert(g), convert(b), a or 1
end
end
-- http://en.wikipedia.org/wiki/SRGB#The_forward_transformation_.28CIE_xyY_or_CIE_XYZ_to_sRGB.29
-- https://en.wikipedia.org/wiki/SRGB#From_CIE_XYZ_to_sRGB
function color.linear_to_gamma(r, g, b, a)
local function convert(c)
if c > 1.0 then
@ -307,13 +338,13 @@ function color.linear_to_gamma(r, g, b, a)
if type(r) == "table" then
local c = {}
for i = 1, 3 do
c[i] = convert(r[i] / 255) * 255
c[i] = convert(r[i])
end
c[4] = convert(r[4] / 255) * 255
c[4] = r[4]
return c
else
return convert(r / 255) * 255, convert(g / 255) * 255, convert(b / 255) * 255, a or 255
return convert(r), convert(g), convert(b), a or 1
end
end
@ -341,24 +372,7 @@ function color.to_string(a)
return string.format("[ %3.0f, %3.0f, %3.0f, %3.0f ]", a[1], a[2], a[3], a[4])
end
function color_mt.__index(t, k)
if type(t) == "cdata" then
if type(k) == "number" then
return t._c[k-1]
end
end
return rawget(color, k)
end
function color_mt.__newindex(t, k, v)
if type(t) == "cdata" then
if type(k) == "number" then
t._c[k-1] = v
end
end
end
color_mt.__index = color
color_mt.__tostring = color.to_string
function color_mt.__call(_, r, g, b, a)

View File

@ -1,24 +1,184 @@
local color = require "modules.color"
local DBL_EPSILON = require("modules.constants").DBL_EPSILON
local function assert_is_float_equal(a, b)
if math.abs(a - b) > DBL_EPSILON then
assert.is.equal(a, b)
end
end
local function assert_is_approx_equal(a, b)
if math.abs(a - b) > 0.001 then
assert.is.equal(a, b)
end
end
describe("color:", function()
it("operators: add, subract, multiply", function()
local c = color(1, 1, 1, 1)
assert.is_true(c:is_color())
local r = c + c
assert.is_true(r:is_color())
assert_is_float_equal(r[1], 2)
assert_is_float_equal(r[2], 2)
assert_is_float_equal(r[3], 2)
r = c - c
assert.is_true(r:is_color())
assert_is_float_equal(r[1], 0)
assert_is_float_equal(r[2], 0)
assert_is_float_equal(r[3], 0)
r = c * 5
assert.is_true(r:is_color())
assert_is_float_equal(r[1], 5)
assert_is_float_equal(r[2], 5)
assert_is_float_equal(r[3], 5)
end)
it("rgb -> hsv -> rgb", function()
local c = color(1,1,1,1)
local hsv = c:color_to_hsv_table()
local c1 = color.hsv_to_color_table(hsv)
local c2 = color.from_hsva(hsv[1], hsv[2], hsv[3], hsv[4])
local c3 = color.from_hsv(hsv[1], hsv[2], hsv[3])
c3[4] = c[4]
for i=1,4 do
assert_is_float_equal(c[i], c1[i])
assert_is_float_equal(c[i], c2[i])
assert_is_float_equal(c[i], c3[i])
end
assert.is_true(c:is_color())
assert.is_true(c1:is_color())
assert.is_true(c2:is_color())
assert.is_true(c3:is_color())
end)
it("hsv -> rgb -> hsv", function()
local hsv1 = { 0, 0.3, 0.8, 0.9 }
for h=0,1, 0.1 do
hsv1[1] = h
local cc = color.hsv_to_color_table(hsv1)
local hsv2 = cc:color_to_hsv_table()
for i=1,4 do
assert_is_approx_equal(hsv1[i], hsv2[i])
end
end
end)
it("unpack", function()
local c = color(122/255, 20/255, 122/255, 255/255)
local r, g, b, a = c:unpack()
assert_is_float_equal(c[1], r)
assert_is_float_equal(c[2], g)
assert_is_float_equal(c[3], b)
assert_is_float_equal(c[4], a)
r, g, b, a = c:as_255()
assert_is_float_equal(122, r)
assert_is_float_equal(20, g)
assert_is_float_equal(122, b)
assert_is_float_equal(255, a)
end)
it("set hsv", function()
-- hsv value conversion values from http://colorizer.org/
local c = color(122/255, 20/255, 122/255, 1)
local hsv = c:color_to_hsv_table()
assert_is_approx_equal(hsv[1], 300/360)
assert_is_approx_equal(hsv[2], 0.8361)
assert_is_approx_equal(hsv[3], 0.4784)
local r = c:hue(200/360)
assert_is_approx_equal(r[1], 20/255)
assert_is_approx_equal(r[2], 88/255)
assert_is_approx_equal(r[3], 122/255)
r = c:saturation(0.2)
assert_is_approx_equal(r[1], 122/255)
assert_is_approx_equal(r[2], 97.6/255)
assert_is_approx_equal(r[3], 122/255)
r = c:value(0.2)
assert_is_approx_equal(r[1], 51/255)
assert_is_approx_equal(r[2], 8.36/255)
assert_is_approx_equal(r[3], 51/255)
end)
it("lighten a color", function()
local c = color(0, 0, 0, 0)
local r = c:lighten(0.1)
assert.is.equal(r[1], 0.1)
r = c:lighten(1000)
assert.is.equal(r[1], 1)
end)
it("darken a color", function()
local c = color(1, 1, 1, 1)
local r = c:darken(0.04)
assert.is.equal(r[1], 0.96)
r = c:darken(1000)
assert.is.equal(r[1], 0)
end)
it("multiply a color by a scalar", function()
local c = color(1, 1, 1, 1)
local r = c:multiply(0.04)
assert.is.equal(r[1], 0.04)
r = c:multiply(0)
for i=1,3 do
assert.is.equal(0, r[i])
end
assert.is.equal(1, r[4])
end)
it("modify alpha", function()
local c = color(1, 1, 1, 1)
local r = c:alpha(0.1)
assert.is.equal(r[4], 0.1)
r = c:opacity(0.5)
assert.is.equal(r[4], 0.5)
r = c:opacity(0.5)
:opacity(0.5)
assert.is.equal(r[4], 0.25)
end)
it("invert", function()
local c = color(1, 0.6, 0.25, 1)
local r = c:invert()
assert_is_float_equal(r[1], 0)
assert_is_float_equal(r[2], 0.4)
assert_is_float_equal(r[3], 0.75)
assert_is_float_equal(r[4], 1)
r = c:invert()
:invert()
for i=1,4 do
assert.is.equal(c[i], r[i])
end
end)
it("lerp", function()
local a = color(1, 0.6, 0.25, 1)
local b = color(1, 0.8, 0.75, 0.5)
local r = a:lerp(b, 0.5)
assert_is_float_equal(r[1], 1)
assert_is_float_equal(r[2], 0.7)
assert_is_float_equal(r[3], 0.5)
assert_is_float_equal(r[4], 0.75)
local r_a = a:lerp(b, 0)
local r_b = a:lerp(b, 1)
for i=1,4 do
assert.is.equal(a[i], r_a[i])
assert.is.equal(b[i], r_b[i])
end
end)
it("linear_to_gamma -> gamma_to_linear round trip", function()
local c = color(0.25, 0.25, 0.25, 1)
local r = color.gamma_to_linear(c:linear_to_gamma())
for i=1,4 do
assert_is_approx_equal(c[i], r[i])
end
end)
end)
--[[
new(r, g, b, a)
from_hsv(h, s, v)
from_hsva(h, s, v, a)
invert(c)
lighten(c, v)
lerp(a, b, s)
darken(c, v)
multiply(c, v)
alpha(c, v)
opacity(c, v)
hue(color, hue)
saturation(color, percent)
value(color, percent)
gamma_to_linear(r, g, b, a)
linear_to_gamma(r, g, b, a)
is_color(a)
to_string(a)
--]]
--]]