カラー名検索

// Euclidean distance in RGB space
function nearestCssColor(hex) {
  const r = parseInt(hex.slice(1, 3), 16)
  const g = parseInt(hex.slice(3, 5), 16)
  const b = parseInt(hex.slice(5, 7), 16)

  let bestName = ''
  let bestDist = Infinity

  for (const [name, value] of Object.entries(cssColors)) {
    const r2 = parseInt(value.slice(1, 3), 16)
    const g2 = parseInt(value.slice(3, 5), 16)
    const b2 = parseInt(value.slice(5, 7), 16)
    const dist = Math.sqrt((r - r2) ** 2 + (g - g2) ** 2 + (b - b2) ** 2)
    if (dist < bestDist) { bestDist = dist; bestName = name }
  }
  return bestName
}

nearestCssColor('#6366f1') // → "SlateBlue"
nearestCssColor('#1e293b') // → "DarkSlateGray"

import math

CSS_COLORS = {
    "Crimson": (220, 20, 60), "SlateBlue": (106, 90, 205),
    "Tomato": (255, 99, 71), "Teal": (0, 128, 128),
    # ... full list of 148 entries
}

def hex_to_rgb(hex_str: str) -> tuple[int, int, int]:
    h = hex_str.lstrip("#")
    return (int(h[0:2], 16), int(h[2:4], 16), int(h[4:6], 16))

def nearest_css_color(hex_str: str) -> str:
    r, g, b = hex_to_rgb(hex_str)
    best = min(
        CSS_COLORS.items(),
        key=lambda item: math.dist((r, g, b), item[1])
    )
    return best[0]

print(nearest_css_color("#6366f1"))  # → SlateBlue
print(nearest_css_color("#ff6347"))  # → Tomato (exact match, distance 0)

package main

import (
	"fmt"
	"math"
	"strconv"
)

type CSSColor struct {
	Name    string
	R, G, B int
}

var colors = []CSSColor{
	{"Crimson", 220, 20, 60},
	{"SlateBlue", 106, 90, 205},
	{"Tomato", 255, 99, 71},
	// ... full list
}

func hexToRGB(hex string) (int, int, int) {
	r, _ := strconv.ParseInt(hex[1:3], 16, 64)
	g, _ := strconv.ParseInt(hex[3:5], 16, 64)
	b, _ := strconv.ParseInt(hex[5:7], 16, 64)
	return int(r), int(g), int(b)
}

func nearest(hex string) string {
	r, g, b := hexToRGB(hex)
	best := ""
	bestDist := math.MaxFloat64
	for _, c := range colors {
		d := math.Sqrt(float64((r-c.R)*(r-c.R) + (g-c.G)*(g-c.G) + (b-c.B)*(b-c.B)))
		if d < bestDist {
			bestDist = d
			best = c.Name
		}
	}
	return best
}

func main() {
	fmt.Println(nearest("#6366f1")) // → SlateBlue
}