update palette.vim

autoload/quickui/palette.vim

@@ -466,6 +466,209 @@ function! quickui#palette#blend(c1, c2, alpha)
 endfunc
 
 
+"----------------------------------------------------------------------
+" palette search in desert256
+"----------------------------------------------------------------------
+
+" returns an approximate grey index for the given grey level
+function! s:grey_number(x)
+	if &t_Co == 88
+		if a:x < 23
+			return 0
+		elseif a:x < 69
+			return 1
+		elseif a:x < 103
+			return 2
+		elseif a:x < 127
+			return 3
+		elseif a:x < 150
+			return 4
+		elseif a:x < 173
+			return 5
+		elseif a:x < 196
+			return 6
+		elseif a:x < 219
+			return 7
+		elseif a:x < 243
+			return 8
+		else
+			return 9
+		endif
+	else
+		if a:x < 14
+			return 0
+		else
+			let l:n = (a:x - 8) / 10
+			let l:m = (a:x - 8) % 10
+			if l:m < 5
+				return l:n
+			else
+				return l:n + 1
+			endif
+		endif
+	endif
+endfunc
+
+" returns the actual grey level represented by the grey index
+function! s:grey_level(n)
+	if &t_Co == 88
+		if a:n == 0
+			return 0
+		elseif a:n == 1
+			return 46
+		elseif a:n == 2
+			return 92
+		elseif a:n == 3
+			return 115
+		elseif a:n == 4
+			return 139
+		elseif a:n == 5
+			return 162
+		elseif a:n == 6
+			return 185
+		elseif a:n == 7
+			return 208
+		elseif a:n == 8
+			return 231
+		else
+			return 255
+		endif
+	else
+		if a:n == 0
+			return 0
+		else
+			return 8 + (a:n * 10)
+		endif
+	endif
+endfunc
+
+" returns the palette index for the given grey index
+function! s:grey_color(n)
+	if &t_Co == 88
+		if a:n == 0
+			return 16
+		elseif a:n == 9
+			return 79
+		else
+			return 79 + a:n
+		endif
+	else
+		if a:n == 0
+			return 16
+		elseif a:n == 25
+			return 231
+		else
+			return 231 + a:n
+		endif
+	endif
+endfunc
+
+" returns an approximate color index for the given color level
+function! s:rgb_number(x)
+	if &t_Co == 88
+		if a:x < 69
+			return 0
+		elseif a:x < 172
+			return 1
+		elseif a:x < 230
+			return 2
+		else
+			return 3
+		endif
+	else
+		if a:x < 75
+			return 0
+		else
+			let l:n = (a:x - 55) / 40
+			let l:m = (a:x - 55) % 40
+			if l:m < 20
+				return l:n
+			else
+				return l:n + 1
+			endif
+		endif
+	endif
+endfunc
+
+" returns the actual color level for the given color index
+function! s:rgb_level(n)
+	if &t_Co == 88
+		if a:n == 0
+			return 0
+		elseif a:n == 1
+			return 139
+		elseif a:n == 2
+			return 205
+		else
+			return 255
+		endif
+	else
+		if a:n == 0
+			return 0
+		else
+			return 55 + (a:n * 40)
+		endif
+	endif
+endfunc
+
+" returns the palette index for the given R/G/B color indices
+function! s:rgb_color(x, y, z)
+	if &t_Co == 88
+		return 16 + (a:x * 16) + (a:y * 4) + a:z
+	else
+		return 16 + (a:x * 36) + (a:y * 6) + a:z
+	endif
+endfunc
+
+" returns the palette index to approximate the given R/G/B color levels
+function! quickui#palette#color_match(r, g, b)
+	" get the closest grey
+	let l:gx = s:grey_number(a:r)
+	let l:gy = s:grey_number(a:g)
+	let l:gz = s:grey_number(a:b)
+
+	" get the closest color
+	let l:x = s:rgb_number(a:r)
+	let l:y = s:rgb_number(a:g)
+	let l:z = s:rgb_number(a:b)
+
+	if l:gx == l:gy && l:gy == l:gz
+		" there are two possibilities
+		let l:dgr = s:grey_level(l:gx) - a:r
+		let l:dgg = s:grey_level(l:gy) - a:g
+		let l:dgb = s:grey_level(l:gz) - a:b
+		let l:dgrey = (l:dgr * l:dgr) + (l:dgg * l:dgg) + (l:dgb * l:dgb)
+		let l:dr = s:rgb_level(l:gx) - a:r
+		let l:dg = s:rgb_level(l:gy) - a:g
+		let l:db = s:rgb_level(l:gz) - a:b
+		let l:drgb = (l:dr * l:dr) + (l:dg * l:dg) + (l:db * l:db)
+		if l:dgrey < l:drgb
+			" use the grey
+			return s:grey_color(l:gx)
+		else
+			" use the color
+			return s:rgb_color(l:x, l:y, l:z)
+		endif
+	else
+		" only one possibility
+		return s:rgb_color(l:x, l:y, l:z)
+	endif
+endfun
+
+function! quickui#palette#rgb_match(rgb) abort
+	if a:rgb =~ '^#'
+		let r = ("0x" . strpart(a:rgb, 1, 2)) + 0
+		let g = ("0x" . strpart(a:rgb, 3, 2)) + 0
+		let b = ("0x" . strpart(a:rgb, 5, 2)) + 0
+	else
+		let r = ("0x" . strpart(a:rgb, 0, 2)) + 0
+		let g = ("0x" . strpart(a:rgb, 2, 2)) + 0
+		let b = ("0x" . strpart(a:rgb, 4, 2)) + 0
+	endif
+	return quickui#palette#color_match(r, g, b)
+endfunc
+
+
 "----------------------------------------------------------------------
 " benchmark
 "----------------------------------------------------------------------