# Idiom #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.

```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)```
```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 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))("#");```
```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();
}```
```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();```
```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;```
`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.```
```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)```
`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)```
```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"`

#### Idiom created by

programming-idioms.org