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Programming-Idioms

# 154 Halfway between two hex color codes
Find color c, the average between colors c1, c2.

c, c1, c2 are strings of hex color codes: 7 chars, beginning with a number sign # .
Assume linear computations, ignore gamma corrections.
New implementation

Be concise.

Be useful.

All contributions dictatorially edited by webmasters to match personal tastes.

Please do not paste any copyright violating material.

Please try to avoid dependencies to third-party libraries and frameworks.

Other implementations 
using System.Drawing;
Color color1 = ColorTranslator.FromHtml(c1);
Color color2 = ColorTranslator.FromHtml(c2);
c = string.Format($"#{((color1.R + color2.R) / 2):X2}{((color1.G + color2.G) / 2):X2}{((color1.B + color2.B) / 2):X2}");
import std.algorithm, std.range; 
import std.conv, std.array, std.format;
string c = roundRobin(c1.dropOne.chunks(2), c2.dropOne.chunks(2))
    .map!(a => a.to!int(16)).array
    .chunks(2)
    .map!(a => ((a[0] + a[1]) / 2))
    .fold!((a,b) => a ~= "%.2X".format(b))("#");
character (len=7) :: c, c1, c2
integer, dimension(3) :: v, v1, v2

read (unit=c1,fmt='(X,3Z2)') v1
read (unit=c2,fmt='(X,3Z2)') v2
v = (v1 + v2)/2
write (unit=c,fmt='("#",3Z2)') v
import "fmt"
import "strconv"
var buf [7]byte
buf[0] = '#'
for i := 0; i < 3; i++ {
	sub1 := c1[1+2*i : 3+2*i]
	sub2 := c2[1+2*i : 3+2*i]
	v1, _ := strconv.ParseInt(sub1, 16, 0)
	v2, _ := strconv.ParseInt(sub2, 16, 0)
	v := (v1 + v2) / 2
	sub := fmt.Sprintf("%02X", v)
	copy(buf[1+2*i:3+2*i], sub)
}
c := string(buf[:])
import "fmt"
import "strconv"
r1, _ := strconv.ParseInt(c1[1:3], 16, 0)
r2, _ := strconv.ParseInt(c2[1:3], 16, 0)
r := (r1 + r2) / 2

g1, _ := strconv.ParseInt(c1[3:5], 16, 0)
g2, _ := strconv.ParseInt(c2[3:5], 16, 0)
g := (g1 + g2) / 2

b1, _ := strconv.ParseInt(c1[5:7], 16, 0)
b2, _ := strconv.ParseInt(c2[5:7], 16, 0)
b := (b1 + b2) / 2

c := fmt.Sprintf("#%02X%02X%02X", r, g, b)
var c = "#";
for(var i = 0; i<3; i++) {
  var sub1 = c1.substring(1+2*i, 3+2*i);
  var sub2 = c2.substring(1+2*i, 3+2*i);
  var v1 = parseInt(sub1, 16);
  var v2 = parseInt(sub2, 16);
  var v = Math.floor((v1 + v2) / 2);
  var sub = v.toString(16).toUpperCase();
  var padsub = ('0'+sub).slice(-2);
  c += padsub;
}
c = "#" + (() => {
  const [p1, p2] = [c1, c2].map((color) => parseInt(color.slice(1), 16)),
    a = [];

  for (let i = 0; i <= 2; i += 1) {
    a.push(Math.floor(((p1 >> (i * 8) & 0xff) + (p2 >> (i * 8) & 0xff)) / 2));
  }

  return a.reverse().map((num) => num.toString(16).padStart(2, "0")).join("");
})();
String r1 = c1.substring(1,3);
String g1 = c1.substring(3,5);
String b1 = c1.substring(5,7);

String r2 = c2.substring(1,3);
String g2 = c2.substring(3,5);
String b2 = c2.substring(5,7);

String r = String.format("%02X", (Integer.parseInt(r1, 16)+Integer.parseInt(r2, 16))/2 );
String g = String.format("%02X", (Integer.parseInt(g1, 16)+Integer.parseInt(g2, 16))/2 );
String b = String.format("%02X", (Integer.parseInt(b1, 16)+Integer.parseInt(b2, 16))/2 );

String c = "#" + r + g + b;
StringBuilder sb = new StringBuilder("#");
for(int i=0;i<3;i++) {
  String sub1 = c1.substring(1+2*i,3+2*i);
  String sub2 = c2.substring(1+2*i,3+2*i);
  int v1 = Integer.parseInt(sub1, 16);
  int v2 = Integer.parseInt(sub2, 16);
  int v = (v1 + v2)/2;
  String sub = String.format("%02X", v);
  sb.append(sub);
}
String c = sb.toString();
import static java.awt.Color.decode;
import java.awt.Color;
Color x = decode(c1), y = decode(c2);
int r = (x.getRed()   + y.getRed())   / 2,
    g = (x.getGreen() + y.getGreen()) / 2,
    b = (x.getBlue()  + y.getBlue())  / 2,
    z = (r << 16) + (g << 8) + b;
String c = "#%06x".formatted(z);
local c = "#"
for i=2,#c1,2 do
	local avg = (tonumber(c1:sub(i,i+1), 16) + tonumber(c2:sub(i,i+1), 16)) / 2
	c = c .. string.format("%02x", math.floor(avg))
end

SysUtils, Graphics
var
  c1, c2: string;
  RGB1, RGB2: LongInt;
  R1, G1, B1, R2, G2, B2: Byte;
  c: TColor;
begin
  RGB1 := ColorToRGB(StrToInt(StringReplace(c1,'#','$',[])));
  RGB1 := ColorToRGB(StrToInt(StringReplace(c2,'#','$',[])));
  RedGreenBlue(RGB1, R1, G1, B1);
  RedGreenBlue(RGB2, R2, G2, B2);
  c := RGBToColor(R1+R2 div 2, G1+G2 div 2, B1+B2 div 2);
end.
use List::SomeUtils qw(pairwise);
my @c1 = unpack 'xA2A2A2', $c1;
my @c2 = unpack 'xA2A2A2', $c2;
my $c = sprintf '#%02X%02X%02X', pairwise { (hex($a) + hex($b)) / 2 } @c1, @c2
import numpy
class RGB(numpy.ndarray):
  @classmethod
  def from_str(cls, rgbstr):
    return numpy.array([
      int(rgbstr[i:i+2], 16)
      for i in range(1, len(rgbstr), 2)
    ]).view(cls)
 
  def __str__(self):
    self = self.astype(numpy.uint8)
    return '#' + ''.join(format(n, 'x') for n in self)
 
c1 = RGB.from_str('#a1b1c1')
print(c1)
c2 = RGB.from_str('#1A1B1C')
print(c2)

print((c1 + c2) / 2)
r1, g1, b1 = [int(c1[p:p+2], 16) for p in range(1,6,2)]
r2, g2, b2 = [int(c2[p:p+2], 16) for p in range(1,6,2)]
c = '#{:02x}{:02x}{:02x}'.format((r1+r2) // 2, (g1+g2) //2, (b1+b2)// 2)
s = slice(1, 7)
x = bytes.fromhex(c1[s])
y = bytes.fromhex(c2[s])
f = lambda x: sum(x) // 2
r, g, b = map(f, zip(x, y))
c = (r << 16) + (g << 8) + b
c = f'#{c:06x}'
rgbs = c1[1..-1].scan(/../), c2[1..-1].scan(/../)
c = "#%02X%02X%02X" % rgbs.transpose.map{|h1, h2| (h1.hex + h2.hex)/2 }
use std::str::FromStr;
use std::fmt;
"Too long for text box, see online demo"

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