mu/505colors.mu

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fn nearest-color-euclidean r: int, g: int, b: int -> _/eax: int {
var result/edi: int <- copy 0x100/invalid
var max-distance/esi: int <- copy 0x30000/max # 3 * 0x100*0x100
var r2/ecx: int <- copy 0
var g2/edx: int <- copy 0
var b2/ebx: int <- copy 0
var color/eax: int <- copy 0
{
compare color, 0x100
break-if->=
$nearest-color-euclidean:body: {
r2, g2, b2 <- color-rgb color
{
var curr-distance/eax: int <- euclidean-distance-squared r, g, b, r2, g2, b2
compare curr-distance, max-distance
break-if->= $nearest-color-euclidean:body
max-distance <- copy curr-distance
}
result <- copy color
}
color <- increment
loop
}
return result
}
fn euclidean-distance-squared r1: int, g1: int, b1: int, r2: int, g2: int, b2: int -> _/eax: int {
var result/edi: int <- copy 0
# red
var tmp/eax: int <- copy r1
tmp <- subtract r2
tmp <- multiply tmp
result <- add tmp
# green
tmp <- copy g1
tmp <- subtract g2
tmp <- multiply tmp
result <- add tmp
# blue
tmp <- copy b1
tmp <- subtract b2
tmp <- multiply tmp
result <- add tmp
return result
}
# Hue/saturation/luminance for an rgb triple.
# rgb are in [0, 256)
# hsl are also returned in [0, 256)
# from https://www.niwa.nu/2013/05/math-behind-colorspace-conversions-rgb-hsl
fn hsl r: int, g: int, b: int -> _/ecx: int, _/edx: int, _/ebx: int {
var _max/eax: int <- maximum r, g
_max <- maximum _max, b
var max/ecx: int <- copy _max
var _min/eax: int <- minimum r, g
_min <- minimum _min, b
var min/edx: int <- copy _min
var luminance/ebx: int <- copy min
luminance <- add max
luminance <- shift-right 1 # TODO: round up instead of down
# if rgb are all equal, it's a shade of grey
compare min, max
{
break-if-!=
return 0, 0, luminance
}
# saturation =
# luminance < 128 | 255*(max-min)/ (max+min)
# otherwise | 255*(max-min)/(2*255 - (max+min))
var nr/esi: int <- copy max
nr <- subtract min
var dr/eax: int <- copy 0
compare luminance, 0x80
{
break-if->=
dr <- copy max
dr <- add min
}
{
break-if-<
dr <- copy 0xff
dr <- shift-left 1
dr <- subtract max
dr <- subtract min
}
var q/xmm0: float <- convert nr
var tmp/xmm1: float <- convert dr
q <- divide tmp
var int-255/eax: int <- copy 0xff
tmp <- convert int-255
q <- multiply tmp
var saturation/esi: int <- convert q
# hue =
# red is max | 256.0/6* (g-b)/(max-min)
# green is max | 256.0/6*(2.0 + (b-r)/(max-min))
# blue is max | 256.0/6*(4.0 + (r-g)/(max-min))
var zero/eax: int <- copy 0
var hue-f/xmm0: float <- convert zero
var dr/eax: int <- copy max
dr <- subtract min
var dr-f/xmm1: float <- convert dr
$hsl:compute-hue-normalized: {
compare r, max
{
break-if-!=
var nr/eax: int <- copy g
nr <- subtract b
hue-f <- convert nr
hue-f <- divide dr-f
break $hsl:compute-hue-normalized
}
compare g, max
{
break-if-!=
var nr/eax: int <- copy b
nr <- subtract r
var f/xmm2: float <- convert nr
f <- divide dr-f
var two/ecx: int <- copy 2
hue-f <- convert two
hue-f <- add f
break $hsl:compute-hue-normalized
}
compare b, max
{
break-if-!=
var nr/eax: int <- copy r
nr <- subtract g
var f/xmm2: float <- convert nr
f <- divide dr-f
var two/ecx: int <- copy 4
hue-f <- convert two
hue-f <- add f
break $hsl:compute-hue-normalized
}
}
var int-256/eax: int <- copy 0x100
var scaling-factor/xmm1: float <- convert int-256
var int-6/eax: int <- copy 6
var six-f/xmm2: float <- convert int-6
scaling-factor <- divide six-f
hue-f <- multiply scaling-factor
var hue/eax: int <- convert hue-f
# if hue < 0, hue = 256 - hue
compare hue, 0
{
break-if->=
var tmp/ecx: int <- copy 0x100
tmp <- subtract hue
hue <- copy tmp
}
return hue, saturation, luminance
}
fn test-hsl-black {
var h/ecx: int <- copy 0
var s/edx: int <- copy 0
var l/ebx: int <- copy 0
h, s, l <- hsl 0, 0, 0
check-ints-equal h, 0, "F - test-hsl-black/hue"
check-ints-equal s, 0, "F - test-hsl-black/saturation"
check-ints-equal l, 0, "F - test-hsl-black/luminance"
}
fn test-hsl-white {
var h/ecx: int <- copy 0
var s/edx: int <- copy 0
var l/ebx: int <- copy 0
h, s, l <- hsl 0xff, 0xff, 0xff
check-ints-equal h, 0, "F - test-hsl-white/hue"
check-ints-equal s, 0, "F - test-hsl-white/saturation"
check-ints-equal l, 0xff, "F - test-hsl-white/luminance"
}
fn test-hsl-grey {
var h/ecx: int <- copy 0
var s/edx: int <- copy 0
var l/ebx: int <- copy 0
h, s, l <- hsl 0x30, 0x30, 0x30
check-ints-equal h, 0, "F - test-hsl-grey/hue"
check-ints-equal s, 0, "F - test-hsl-grey/saturation"
check-ints-equal l, 0x30, "F - test-hsl-grey/luminance"
}
# red hues: 0-0x54
fn test-hsl-slightly-red {
var h/ecx: int <- copy 0
var s/edx: int <- copy 0
var l/ebx: int <- copy 0
h, s, l <- hsl 0xff, 0xfe, 0xfe
check-ints-equal h, 0, "F - test-hsl-slightly-red/hue"
check-ints-equal s, 0xff, "F - test-hsl-slightly-red/saturation"
check-ints-equal l, 0xfe, "F - test-hsl-slightly-red/luminance" # TODO: should round up
}
fn test-hsl-extremely-red {
var h/ecx: int <- copy 0
var s/edx: int <- copy 0
var l/ebx: int <- copy 0
h, s, l <- hsl 0xff, 0, 0
check-ints-equal h, 0, "F - test-hsl-extremely-red/hue"
check-ints-equal s, 0xff, "F - test-hsl-extremely-red/saturation"
check-ints-equal l, 0x7f, "F - test-hsl-extremely-red/luminance" # TODO: should round up
}
# green hues: 0x55-0xaa
fn test-hsl-slightly-green {
var h/ecx: int <- copy 0
var s/edx: int <- copy 0
var l/ebx: int <- copy 0
h, s, l <- hsl 0xfe, 0xff, 0xfe
check-ints-equal h, 0x55, "F - test-hsl-slightly-green/hue"
check-ints-equal s, 0xff, "F - test-hsl-slightly-green/saturation"
check-ints-equal l, 0xfe, "F - test-hsl-slightly-green/luminance" # TODO: should round up
}
fn test-hsl-extremely-green {
var h/ecx: int <- copy 0
var s/edx: int <- copy 0
var l/ebx: int <- copy 0
h, s, l <- hsl 0, 0xff, 0
check-ints-equal h, 0x55, "F - test-hsl-extremely-green/hue"
check-ints-equal s, 0xff, "F - test-hsl-extremely-green/saturation"
check-ints-equal l, 0x7f, "F - test-hsl-extremely-green/luminance" # TODO: should round up
}
# blue hues: 0xab-0xff
fn test-hsl-slightly-blue {
var h/ecx: int <- copy 0
var s/edx: int <- copy 0
var l/ebx: int <- copy 0
h, s, l <- hsl 0xfe, 0xfe, 0xff
check-ints-equal h, 0xab, "F - test-hsl-slightly-blue/hue"
check-ints-equal s, 0xff, "F - test-hsl-slightly-blue/saturation"
check-ints-equal l, 0xfe, "F - test-hsl-slightly-blue/luminance" # TODO: should round up
}
fn test-hsl-extremely-blue {
var h/ecx: int <- copy 0
var s/edx: int <- copy 0
var l/ebx: int <- copy 0
h, s, l <- hsl 0, 0, 0xff
check-ints-equal h, 0xab, "F - test-hsl-extremely-blue/hue"
check-ints-equal s, 0xff, "F - test-hsl-extremely-blue/saturation"
check-ints-equal l, 0x7f, "F - test-hsl-extremely-blue/luminance" # TODO: should round up
}
# cyan: 0x7f
fn test-hsl-cyan {
var h/ecx: int <- copy 0
var s/edx: int <- copy 0
var l/ebx: int <- copy 0
h, s, l <- hsl 0, 0xff, 0xff
check-ints-equal h, 0x80, "F - test-hsl-cyan/hue"
check-ints-equal s, 0xff, "F - test-hsl-cyan/saturation"
check-ints-equal l, 0x7f, "F - test-hsl-cyan/luminance" # TODO: should round up
}
fn nearest-color-euclidean-hsl h: int, s: int, l: int -> _/eax: int {
var result/edi: int <- copy 0x100/invalid
var max-distance/esi: int <- copy 0x30000/max # 3 * 0x100*0x100
var a/ecx: int <- copy 0
var b/edx: int <- copy 0
var c/ebx: int <- copy 0
var color/eax: int <- copy 0
{
compare color, 0x100
break-if->=
$nearest-color-euclidean-hsl:body: {
a, b, c <- color-rgb color
a, b, c <- hsl a, b, c
{
var curr-distance/eax: int <- euclidean-hsl-squared a, b, c, h, s, l
compare curr-distance, max-distance
break-if->= $nearest-color-euclidean-hsl:body
max-distance <- copy curr-distance
}
result <- copy color
}
color <- increment
loop
}
return result
}
fn test-nearest-color-euclidean-hsl {
# red from lightest to darkest
var red/eax: int <- nearest-color-euclidean-hsl 0, 0xff, 0xff
check-ints-equal red, 0x58/88, "F - test-nearest-color-euclidean-hsl/full-red1"
red <- nearest-color-euclidean-hsl 0, 0xff, 0xc0
check-ints-equal red, 0x40/64, "F - test-nearest-color-euclidean-hsl/full-red2"
red <- nearest-color-euclidean-hsl 0, 0xff, 0x80
check-ints-equal red, 0x28/40, "F - test-nearest-color-euclidean-hsl/full-red3"
red <- nearest-color-euclidean-hsl 0, 0xff, 0x40
check-ints-equal red, 0x28/40, "F - test-nearest-color-euclidean-hsl/full-red4"
red <- nearest-color-euclidean-hsl 0, 0xff, 0
check-ints-equal red, 0x28/40, "F - test-nearest-color-euclidean-hsl/full-red5"
# try a number really close to red but on the other side of the cylinder
red <- nearest-color-euclidean-hsl 0xff, 0xff, 0xff
#? draw-int32-decimal-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, red, 7/fg 0/bg
check-ints-equal red, 0x57/87, "F - test-nearest-color-euclidean-hsl/other-end-of-red" # still looks red
# half-saturation red from lightest to darkest
red <- nearest-color-euclidean-hsl 0, 0x80, 0xff
check-ints-equal red, 0xf/15, "F - test-nearest-color-euclidean-hsl/half-red1" # ?? grey ??
red <- nearest-color-euclidean-hsl 0, 0x80, 0xc0
check-ints-equal red, 4, "F - test-nearest-color-euclidean-hsl/half-red2"
red <- nearest-color-euclidean-hsl 0, 0x80, 0x80
check-ints-equal red, 4, "F - test-nearest-color-euclidean-hsl/half-red3"
red <- nearest-color-euclidean-hsl 0, 0x80, 0x40
check-ints-equal red, 4, "F - test-nearest-color-euclidean-hsl/half-red4"
red <- nearest-color-euclidean-hsl 0, 0x80, 0
check-ints-equal red, 0x70/112, "F - test-nearest-color-euclidean-hsl/half-red5"
}
fn euclidean-hsl-squared h1: int, s1: int, l1: int, h2: int, s2: int, l2: int -> _/eax: int {
var result/edi: int <- copy 0
# hue
var tmp/eax: int <- copy h1
tmp <- subtract h2
tmp <- multiply tmp
# TODO: should we do something to reflect that hue is a cylindrical space?
# I can't come up with a failing test.
result <- add tmp
# saturation
tmp <- copy s1
tmp <- subtract s2
tmp <- multiply tmp
result <- add tmp
# luminance
tmp <- copy l1
tmp <- subtract l2
tmp <- multiply tmp
result <- add tmp
return result
}
###
fn maximum a: int, b: int -> _/eax: int {
var a2/eax: int <- copy a
compare a2, b
{
break-if-<
return a
}
return b
}
fn minimum a: int, b: int -> _/eax: int {
var a2/eax: int <- copy a
compare a2, b
{
break-if->
return a
}
return b
}