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@delphinus delphinus/colorwheel.vim

Last active Nov 20, 2019
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Draw color wheel in NeoVim
const s:pi2 = 2 * 3.14159265
" pixel_ratio means the ratio of the character size.
const s:pixel_ratio = 2.0 / 1.0
" ColorWheel draws a color wheel
function! ColorWheel() abort
const [center_x, center_y] = [&columns / 2.0, &lines / 2.0]
const radius = min([&columns, &lines]) / 8.0 * 3
" loop over the distance multiplied by pixel_ratio in the horizontal
" direction because the character has a rectangular shape.
let col = center_x - radius * s:pixel_ratio
while col < center_x + radius * s:pixel_ratio
let row = center_y - radius
while row < center_y + radius
" calculate the coordinate mathematically
let [x, y] = [(col - center_x) / s:pixel_ratio, center_y - row]
" distance from the center max to 1.0
let r = sqrt(x * x + y * y) / radius
if r <= 1.0
let [i_col, i_row] = [float2nr(col), float2nr(row)]
" open a float window with 1x1 size
let winid = nvim_open_win(bufnr(''), v:false, {
\ 'relative': 'win',
\ 'width': 1, 'height': 1,
\ 'col': i_col, 'row': i_row,
\ })
let hl_name = 'CircleBG' . i_col . i_row
execute 'hi' hl_name 'guibg=' . PositionToRGB(x, y, r)
call nvim_win_set_option(winid, 'winhighlight', 'Normal:' . hl_name)
endif
let row += 1
endwhile
let col += 1
endwhile
endfunction
" PositionToRGB converts the coordinate into the color in RGB representation.
function! PositionToRGB(x, y, r) abort
const theta = atan2(a:y, a:x)
const angle = theta >= 0 ? theta : theta + s:pi2
" TODO: enable to change v
const [h, s, v] = [angle / s:pi2, a:r, 1.0]
" Convert HSV to RGB
if v == 0
let rgb = [0, 0, 0]
elseif s == 0
let rgb = [v, v, v]
else
const chroma = s * v
const min_v = v - chroma
if h >= 2.0 / 3
const temp = (h - 2.0 / 3) * 6
let rgb = temp < 1 ? [v * temp, 0, v] : [v, 0, v * (2 - temp)]
elseif h >= 1.0 / 3
const temp = (h - 1.0 / 3) * 6
let rgb = temp < 1 ? [0, v, v * temp] : [0, v * (2 - temp), v]
else
const temp = h * 6
let rgb = temp < 1 ? [v, v * temp, 0] : [v * (2 - temp), v, 0]
endif
for i in [0, 1, 2]
let rgb[i] = rgb[i] / v * (v - min_v) + min_v
endfor
endif
let color = '#'
for c in rgb
let color .= printf('%02x', float2nr(c * 255))
endfor
return color
endfunction
@delphinus

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delphinus commented Jun 29, 2019

This script needs the latest NeoVim with features: floating windows.

スクリーンショット 0001-06-30 10 05 43

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