Questions tagged [color]

Challenge involving processing colors. It can be either for graphical output or manipulation on color codes.

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3 votes
4 answers

A randomly colored walk

Given two inputs, a distance \$d\$ and a number \$n\$ output a list of \$n\$ random colors which each have distance \$d\$ from the previous. Background A random walk is a path which is defined by ...
20 votes
50 answers

RGB to hexadecimal

Based off a Scratch project The pen extension in Scratch has a set pen color to () block. The () is normally a color dropdown, ...
-5 votes
6 answers

I'm Blue, Da ba dee da ba die

Write a program, which outputs I'm Blue, and then Da, Ba, Dee, Da, Ba, Die, forever, the words must be space-seperated in one ...
42 votes
15 answers

IE's Extra Robust Color Parsing®

Recently, I've found a rant from 2004 about Internet Explorer's color parsing. Turns out, MS made sure that just about anything will be parsed as a color somehow and I think it makes for a neat ...
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0 votes
0 answers

Invert colors given a hex color code [duplicate]

So the challenge is, given a string containing a hex color code, write a function in any programming language that takes the string and inverts the color, e.g., ...
8 votes
1 answer

Colorize a diff in unified format

Introduction git diff is a great way to export patches of the source code, and its outputs are colorized if you don't pass extra arguments to it. However, when you ...
  • 241
19 votes
5 answers

Generate Green Spray Paint Patterns

This challenge is about creating these neat "green spray paint" patterns: (more pictures below) Loosely explained, they are generated by starting with a black image and a point in the center. ...
15 votes
8 answers

Decorate Pascal's Triangle

Although what is a Pascal's triangle is well-known and we already can generate it, the task is now different: Output \$n\$ first lines of the Pascal's triangle as colored bricks. Color number is ...
13 votes
7 answers

Find the closest HTML colour name

Input A single hex 6-digit colour code, capital letter, without #. Can also be a 24-bit integer if you prefer. Output The closest HTML color name (e.g ...
24 votes
23 answers

Find the closest three-digit hex colour

In CSS, colours can be specified by a "hex triplet" - a three byte (six digit) hexadecimal number where each byte represents the red, green, or blue components of the colour. For instance, ...
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8 votes
11 answers

Color of a Pixel

Write a program that prints the RGB color of a given pixel on the screen. The program should read a line from stdin in the format x,y, where x and y are unsigned ...
  • 223
-2 votes
4 answers

Find the closest RGB color [closed]

Input: A valid 6 HEX digit color code wihout a # prefix Valid: 000000 FF00FF ABC123 Your job is to find to which one of these: ...
  • 437
13 votes
33 answers

True color code

True color (24-bit) at Wikipedia is described in pertinent part as 24 bits almost always uses 8 bits of each of R, G, B. As of 2018 24-bit color depth is used by virtually every computer and ...
18 votes
19 answers

Read color in my way

Different systems have different ways to describe colors, even if all of them are speaking in R-G-B-A space. A front-end developer who is familiar with CSS may prefer ...
  • 32.8k
21 votes
42 answers

The next colour

Challenge Consider the rainbow as seven colours, represented by strings as Red Orange Yellow Green Blue Indigo Violet. Your task is to create a program that ...
  • 846
14 votes
6 answers

RGB to Xterm Color Converter

256-color Xterm-compatible terminals add 240 colors on top of the usual 16 system colors. Colors 16-231 use 6 levels (0, 95, 135, 175, 215, 255) of red, green, and blue, ordered lexicographically. ...
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18 votes
10 answers

HSL to RGB values

The main purpose of the RGB (Red Green Blue) color model is for the sensing, representation and display of images in electronic systems, such as televisions and computers HSL (Hue Saturation Lightness)...
  • 346
4 votes
18 answers

Convert RGB color to websafe

Web safe colors are in intervals of 51, they include 0, 3, 6, 9, c, and, f as digits in hex (such as #993333), or 0, 51, 102, 153, 204, 255 in decimal. Your task today is convert a given color to a ...
  • 443
9 votes
16 answers

Convert CMYK values to RGB

Given Color codes in CMYK, convert it to RGB value. Input: string of 4 integers(ranging from 0-100) separated by space 86 86 0 43 28 14 0 6 0 41 73 4 Output: ...
  • 1,750
13 votes
21 answers

How to convert HEX2 to RGBA?

The world of art is full of colour, but the world of the network is even fuller than the world of art of diferent colours and it's renderings. That's why we need to know how to convert one type of ...
  • 165
49 votes
50 answers

Display random colored pixels

I've always liked screens full of randomly colored pixels. They're interesting to look at and the programs that draw them are fun to watch. The challenge Fill your screen, or a graphical window, ...
  • 13.5k
46 votes
25 answers

Better Hex Color Codes for Your Internet

Hex triplets such as #ffffff (white) or #3764ef (blueish) are often used to denote RGB colors. They consist of ...
17 votes
21 answers

Vacancy or no vacancy?

We've all seen the signs on motels telling us if there's a vacancy or not: Typically, these will permanently have the letters of VACANCY lit up, and have the letters of NO lit up if there isn't any ...
  • 13.5k
22 votes
16 answers

Extract an RGB channel of an image

Given an image, either as input (possibly in RGB triplets) or with the filename as input (you may assume the image has a specific filename, possibly without an extension), output an image representing ...
  • 7,710
23 votes
10 answers

Two-Coloring Overlapping Circles

Write a program or function that takes in the following input in a reasonable format of your choice: Two positive integers W and H that define the width and height of the image you'll be generating. ...
117 votes
62 answers


Today is November 8th, 2016, Election Day in the United States of America. If you are a U.S. citizen eligible to vote, then go out and vote if you haven't already before answering this challenge. Do ...
19 votes
10 answers

RGB Gradients Generation

The Challenge Given the two uppercase hexadecimal strings (both 6 characters long, XXXXXX and YYYYYY) representing RGB values (ranging from 000000 to ...
7 votes
14 answers

Use 16 colors while writing Hey! 4 times

i.e each byte appears in a different ANSI shell colour. Rules Resetting the color of the shell after output is not required Must be output in STDOUT or the primary colour text output of your language....
  • 737
19 votes
14 answers

The Camouflage Color Changing Chameleon Challenge

Chameleon challenges are a bad thing, apparently. Too bad, chameleons are beautiful creatures. Time for a change! As we all know, many chameleons posses a remarkable ability to blend in with their ...
  • 2,046
9 votes
13 answers

From Rgb to Cmyk

Given 3 bytes or RGB as input, calculate the nearest CMYK values, and output them. create either a function with parameters and return value or a program that operates on stdin/stdout use the color ...
  • 14.6k
15 votes
11 answers

Color count, sorted by occurences

This one is simple to describe and I could hardly believe that this was not golfed before: For a given image (whatever format is supported by your language), find the unique colors and output a list ...
25 votes
3 answers

Rainbowlify An Image

This challenge is about gradually shifting hues in an image to make pretty pictures like this: (original) Challenge Write a program or function that takes in two non-negative integers and an image in ...
385 votes
36 answers

American Gothic in the palette of Mona Lisa: Rearrange the pixels

You are given two true color images, the Source and the Palette. They do not necessarily have the same dimensions but it is guaranteed that their areas are the same, i.e. they have the same number of ...
460 votes
50 answers

Images with all colors

Similar to the images on, make images where each pixel is a unique color (no color is used twice and no color is missing). Give a program that generates such an image, along with a ...