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Relax color parser based on the current and upcoming CSS specs
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This adds supports for:
- fractional RGB values, e.g. "rgb(255.0, 0.0, 0.0)"
- fractional percentages, e.g. "rgb(1e2%, 34.5%, .6%)"
- more clamping, e.g. "hsla(0, -10%, 120%, 1.5)"
- hue angle units, e.g. "turn", "rad"
- case-insensitive function names, e.g. "Rgb(0, 0, 0)"

This throws an error when mixing percentages and numbers, e.g. "rgb(100%, 128, 0%)".
This also changes the type of the errors from `ErrorException` to `ArgumentError`.
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@kimikage
kimikage committed May 29, 2021
1 parent 81aaf1e commit 6b437ab
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192 changes: 117 additions & 75 deletions src/parse.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -5,124 +5,144 @@ include("names_data.jl")
# Color Parsing
# -------------

const col_pat_hex = r"^\s*(#|0x)([[:xdigit:]]{3,8})\s*$"
const col_pat_rgb = r"^\s*rgb\(\s*(\d+%?)\s*[,\s]\s*(\d+%?)\s*[,\s]\s*(\d+%?)\s*\)\s*$"
const col_pat_hsl = r"^\s*hsl\(\s*(\d+%?)\s*[,\s]\s*(\d+%?)\s*[,\s]\s*(\d+%?)\s*\)\s*$"
const col_pat_rgba = r"^\s*rgba?\(\s*(\d+%?)\s*[,\s]\s*(\d+%?)\s*[,\s]\s*(\d+%?)\s*[,/]\s*((?:\d+|(?=\.\d))(?:\.\d*)?%?)\s*\)\s*$"
const col_pat_hsla = r"^\s*hsla?\(\s*(\d+%?)\s*[,\s]\s*(\d+%?)\s*[,\s]\s*(\d+%?)\s*[,/]\s*((?:\d+|(?=\.\d))(?:\.\d*)?%?)\s*\)\s*$"
const col_pat_func3 = r"^\s*(?:rgba?|hsla?)
\(\s*([^\s,/\)]+)\s*
[,\s]\s*([^\s,/\)]+)\s*
[,\s]\s*([^\s,/\)]+)\s*
(?:[,/]\s*([^\s,/\)]+)\s*)?\)\s*$"ix
const col_pat_hex = r"^\s*(?:#|0x)([[:xdigit:]]{3,8})\s*$"
const col_pat_unitful = r"^([+-]?(?:\d+\.?\d*|\.\d+)(?:e[+-]?\d+)?)(.*)$"i

chop1(x) = SubString(x, 1, lastindex(x) - 1) # `chop` is slightly slow

function parse_hex(hex::SubString{String}) # It is guaranteed to be a valid hex string.
digits = UInt32(0)
for d in codeunits(hex)
dl = d | 0x20
digits = (digits << 0x4) + dl - (dl < UInt8('a') ? UInt8('0') : UInt8('a') - 0xa)
end
return digits
end

function tryparse_dec(dec::SubString{String})
de = 0
for d in codeunits(dec)
dx = d - UInt8('0')
0x0 <= dx <= 0x9 || return nothing
de = de * 10 + dx
end
return de
end

function parse_f32(dec::SubString{String})
v = tryparse_dec(dec)
v === nothing && return parse(Float32, dec)
Float32(v)
end

# Parse a number used in the "rgb()" or "hsl()" color.
function parse_rgb(num::AbstractString)
if @inbounds num[end] == '%'
return N0f8(clamp(parse(Int, chop1(num), base=10) / 100, 0, 1))
else
v = clamp(parse(Int, num, base=10), 0, 255)
return reinterpret(N0f8, unsafe_trunc(UInt8, v))

function parse_rgb(num::SubString{String})
@inbounds num[end] == '%' && throw_rgb_unification_error()
v = tryparse_dec(num)
if v === nothing
v = round(Int, parse(Float32, num))
end
return reinterpret(N0f8, unsafe_trunc(UInt8, clamp(v, 0, 255)))
end

function parse_hsl_hue(num::AbstractString)
if @inbounds num[end] == '%'
error("hue cannot end in %")
else
return parse(Int, num, base=10)
function parse_rgb_pc(num::SubString{String})
@inbounds num[end] == '%' || throw_rgb_unification_error()
v = round(Int, parse_f32(chop1(num)) * 2.55f0)
return reinterpret(N0f8, unsafe_trunc(UInt8, clamp(v, 0, 255)))
end

function throw_rgb_unification_error()
throw(ArgumentError("RGB values should be unified in numbers in [0,255] or percentages."))
end

function parse_hue(num::SubString{String})
mat = match(col_pat_unitful, num)
if mat !== nothing
v0, unit0 = mat.captures
v = parse_f32(v0)
isempty(unit0) && return v
unit = lowercase(unit0)
if unit == "deg"
return v
elseif unit == "turn"
return v * 360f0
elseif unit == "rad"
return rad2deg(v)
elseif unit == "grad"
return v * 0.9f0
end
end
throw(ArgumentError("invalid hue notation: $num"))
end

function parse_hsl_sl(num::AbstractString)
function parse_hsl_pc(num::SubString{String})
if @inbounds num[end] != '%'
error("saturation and lightness must end in %")
else
return parse(Int, chop1(num), base=10) / 100
throw(ArgumentError("saturation and lightness must end in %"))
end
return clamp(parse_f32(chop1(num)) / 100f0, 0.0f0, 1.0f0)
end

# Parse a number used in the alpha field of "rgba()" and "hsla()".
function parse_alpha_num(num::AbstractString)
function parse_alpha(num::SubString{String})
if @inbounds num[end] == '%'
return parse(Int, chop1(num), base=10) / 100f0
v = parse_f32(chop1(num)) / 100f0
else
# `parse(Float32, num)` is somewhat slow on Windows(x86_64-w64-mingw32).
# However, the following has the opposite effect on Linux.
# m = match(r"0?\.(\d{1,9})", num)
# if m != nothing
# d = m.captures[1]
# return parse(Int, d, base=10) / Float32(exp10(length(d)))
# end
return parse(Float32, num)
v = parse(Float32, num)
end
return clamp(v, 0.0f0, 1.0f0)
end

function _parse_colorant(desc::String)
n0f8(x) = reinterpret(N0f8, unsafe_trunc(UInt8, x))
mat = match(col_pat_hex, desc)
if mat !== nothing
prefix, len = mat.captures[1], length(mat.captures[2])
digits = parse(UInt32, mat.captures[2], base=16)
len = ncodeunits(mat[1])
digits = parse_hex(mat[1])
if len == 6
return convert(RGB{N0f8}, reinterpret(RGB24, digits))
elseif len == 3
return RGB(n0f8((digits>>8) & 0xF * 0x11),
n0f8((digits>>4) & 0xF * 0x11),
n0f8((digits>>0) & 0xF * 0x11))
elseif len == 8
if prefix[1] == '0'
return ARGB{N0f8}(n0f8(digits>>16),
n0f8(digits>> 8),
n0f8(digits>> 0),
n0f8(digits>>24))
else
if occursin('#', desc)
return RGBA{N0f8}(n0f8(digits>>24),
n0f8(digits>>16),
n0f8(digits>> 8),
n0f8(digits>> 0))
else
return ARGB{N0f8}(n0f8(digits>>16),
n0f8(digits>> 8),
n0f8(digits>> 0),
n0f8(digits>>24))
end
elseif len == 4
if prefix[1] == '0'
return ARGB{N0f8}(n0f8((digits>> 8) & 0xF * 0x11),
n0f8((digits>> 4) & 0xF * 0x11),
n0f8((digits>> 0) & 0xF * 0x11),
n0f8((digits>>12) & 0xF * 0x11))
else
if occursin('#', desc)
return RGBA{N0f8}(n0f8((digits>>12) & 0xF * 0x11),
n0f8((digits>> 8) & 0xF * 0x11),
n0f8((digits>> 4) & 0xF * 0x11),
n0f8((digits>> 0) & 0xF * 0x11))
else
return ARGB{N0f8}(n0f8((digits>> 8) & 0xF * 0x11),
n0f8((digits>> 4) & 0xF * 0x11),
n0f8((digits>> 0) & 0xF * 0x11),
n0f8((digits>>12) & 0xF * 0x11))
end
end
end
mat = match(col_pat_rgb, desc)
if mat !== nothing
return RGB{N0f8}(parse_rgb(mat.captures[1]),
parse_rgb(mat.captures[2]),
parse_rgb(mat.captures[3]))
end

mat = match(col_pat_hsl, desc)
if mat !== nothing
T = ColorTypes.eltype_default(HSL)
return HSL{T}(parse_hsl_hue(mat.captures[1]),
parse_hsl_sl(mat.captures[2]),
parse_hsl_sl(mat.captures[3]))
end

mat = match(col_pat_rgba, desc)
if mat !== nothing
return RGBA{N0f8}(parse_rgb(mat.captures[1]),
parse_rgb(mat.captures[2]),
parse_rgb(mat.captures[3]),
parse_alpha_num(mat.captures[4]))
end

mat = match(col_pat_hsla, desc)
if mat !== nothing
T = ColorTypes.eltype_default(HSLA)
return HSLA{T}(parse_hsl_hue(mat.captures[1]),
parse_hsl_sl(mat.captures[2]),
parse_hsl_sl(mat.captures[3]),
parse_alpha_num(mat.captures[4]))
mat = match(col_pat_func3, desc)
if mat !== nothing #&& mat[1] !== nothing && mat[2] !== nothing && mat[3] !== nothing
if occursin(r"^\s*rgb"i, desc)
return _parse_colorant_rgb(mat[1], mat[2], mat[3], mat[4])
else # occursin(r"^\s*hsl"i, desc)
return _parse_colorant_hsl(mat[1], mat[2], mat[3], mat[4])
end
end

sdesc = strip(desc)
Expand All @@ -142,7 +162,29 @@ function _parse_colorant(desc::String)
return RGB{N0f8}(n0f8(c[1]), n0f8(c[2]), n0f8(c[3]))
end

error("Unknown color: ", desc)
throw(ArgumentError("Unknown color: $desc"))
end

function _parse_colorant_rgb(p1, p2, p3, alpha)
if @inbounds p1[end] == '%'
r, g, b = parse_rgb_pc(p1), parse_rgb_pc(p2), parse_rgb_pc(p3)
else
r, g, b = parse_rgb(p1), parse_rgb(p2), parse_rgb(p3)
end
if alpha === nothing
return RGB{N0f8}(r, g, b)
else
return RGBA{N0f8}(r, g, b, parse_alpha(alpha) % N0f8)
end
end

function _parse_colorant_hsl(p1, p2, p3, alpha)
h, s, l = parse_hue(p1), parse_hsl_pc(p2), parse_hsl_pc(p3)
if alpha === nothing
return typeof(HSL(0,0,0))(h, s, l)
else
return typeof(HSLA(0,0,0))(h, s, l, parse_alpha(alpha))
end
end

"""
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25 changes: 15 additions & 10 deletions test/parse.jl
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Original file line number Diff line number Diff line change
@@ -1,3 +1,4 @@
using Test, Colors
using FixedPointNumbers

@testset "Parse" begin
Expand All @@ -10,7 +11,7 @@ using FixedPointNumbers
@test redN0f8 === RGB{N0f8}(1,0,0)
@test parse(RGB{Float64}, "red") === RGB{Float64}(1,0,0)
@test isa(parse(HSV, "blue"), HSV)
@test_throws ErrorException parse(Colorant, "p ink")
@test_throws ArgumentError parse(Colorant, "p ink")
@test parse(Colorant, "transparent") === RGBA{N0f8}(0,0,0,0)
@test parse(Colorant, "\nSeaGreen ") === RGB{N0f8}(r8(0x2E),r8(0x8B),r8(0x57))
@test parse(Colorant, "sea GREEN") === colorant"seagreen"
Expand All @@ -23,29 +24,33 @@ using FixedPointNumbers
@test parse(Colorant, "0xFB0A") === ARGB(r8(0xBB),r8(0x00),r8(0xAA),r8(0xFF))
@test parse(Colorant, "#FFBB00AA") === RGBA(r8(0xFF),r8(0xBB),r8(0x00),r8(0xAA))
@test parse(Colorant, "0xFFBB00AA") === ARGB(r8(0xBB),r8(0x00),r8(0xAA),r8(0xFF))
@test_throws ErrorException parse(Colorant, "#BAD05")
@test_throws ErrorException parse(Colorant, "#BAD0007")
@test_throws ErrorException parse(Colorant, "#BAD000009")
@test_throws ArgumentError parse(Colorant, "#BAD05")
@test_throws ArgumentError parse(Colorant, "#BAD0007")
@test_throws ArgumentError parse(Colorant, "#BAD000009")

# rgb()
@test parse(Colorant, "rgb(55,217,127)") === RGB{N0f8}(r8(0x37),r8(0xd9),r8(0x7f))
@test colorant" rgb( 55, 217, 127 ) " === RGB{N0f8}(r8(0x37),r8(0xd9),r8(0x7f))
@test colorant" Rgb( 55, 217, 127 ) " === RGB{N0f8}(r8(0x37),r8(0xd9),r8(0x7f))
@test parse(Colorant, "rgb(22%,85%,50%)") === RGB{N0f8}(r8(0x38),r8(0xd9),r8(0x80))
@test parse(Colorant, "rgba(55,217,127,0.5)") === RGBA{N0f8}(r8(0x37),r8(0xd9),r8(0x7f),0.5)
@test parse(Colorant, "rgb( 55,217,127,50%)") === RGBA{N0f8}(r8(0x37),r8(0xd9),r8(0x7f),0.5) # CSS Color Module Level 4
@test parse(Colorant, "rgb( 55 217 127 /.5)") === RGBA{N0f8}(r8(0x37),r8(0xd9),r8(0x7f),0.5) # CSS Color Module Level 4
@test parse(Colorant, "rgb(55, 85%, 50%)") === RGB{N0f8}(r8(0x37),r8(0xd9),r8(0x80)) # this is invalid according to CSS spec.
@test_throws ErrorException parse(Colorant, "rgb(21.6%,85%,50%)") # this is valid but not supported
@test_throws ArgumentError parse(Colorant, "rgb(55, 85%, 50%)") # this is invalid according to CSS spec.
@test parse(Colorant, "rgb(21.6%,85%,50%)") === RGB{N0f8}(r8(0x37),r8(0xd9),r8(0x80))

# hsl()
@test parse(Colorant, "hsl(120, 100%, 50%)") === HSL{Float32}(120,1.0,.5)
@test colorant" hsl( 120, 100%, 50% ) " === HSL{Float32}(120,1.0,.5)
@test colorant" Hsl( 120, 100%, 50% ) " === HSL{Float32}(120,1.0,.5)
@test parse(RGB{N0f8},"hsl(120, 100%, 50%)") === convert(RGB{N0f8}, HSL{Float32}(120,1.0,.5))
@test_throws ErrorException parse(Colorant, "hsl(120, 100, 50)")
@test_throws ErrorException parse(Colorant, "hsl(120%,100%,50%)")
@test_throws ArgumentError parse(Colorant, "hsl(120, 100, 50)")
@test_throws ArgumentError parse(Colorant, "hsl(120%,100%,50%)")
@test parse(Colorant, "hsla(120,50%,7%, .6)") === HSLA{Float32}(120,.5,.07,.6)
@test parse(Colorant, "hsl( 120,50%,7%,60%)") === HSLA{Float32}(120,.5,.07,.6) # CSS Color Module Level 4
@test parse(Colorant, "hsl( 120 50% 7% / 1)") === HSLA{Float32}(120,.5,.07, 1) # CSS Color Module Level 4
@test parse(Colorant, "hsl( 90Deg, 100%, 0%)") === HSL{Float32}(90, 1, 0)
@test parse(Colorant, "hsl( 0.25turn, 120%, 0.0%)") === HSL{Float32}(90, 1, 0)
@test parse(Colorant, "hsl(1.57079633RAD, 100%, -10%)") === HSL{Float32}(90, 1, 0)
@test parse(Colorant, "hsl( 100grad, 100%, 0e2%)") === HSL{Float32}(90, 1, 0)

@test parse(Colorant, :red) === colorant"red"
@test_deprecated parse(Colorant, colorant"red") === colorant"red"
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