any2coloring

Create pixel-art like coloring pages from any pictures.

Description

This program allows to create coloring pages with a pixel-art look from any picture supported by G'MIC.

The low-resolution 'pixel-art' picture is obtained with G'MIC, using a ministeck-inspired procedure. The colors used to map the picture are provided by the user.

Palette file

The colors used to index the coloring page are extracted from the palette file. This file must have two columns, separated by a blank character (tab or space). The first column contains the RGB code of the color as a 6-digit hexadecimal number (web-like formatted, without the leading #). The second column contains a color identifier, printed on the pixel-art picture. Works best if the identifier is made of one or two caracters.

art_grip_aquarelle_36.csv is an example for the Art GRIP Aquerelle 36 pencil box from Faber-Castell (see here). The RGB values were extracted from the pdf palette and may not reflect the real color of every pencil... The last two numbers printed on each pencil are used as the color code.

Installation

Dependencies

• G'MIC as a library. You may have to modify the provided pro file if qmake doesn't find it.
• CImg (it's a build-time dependency of G'MIC)
• Qt version 5 is supported, 6 may be compatible but not tested.
• pkg-config, used to resolve gmic libX11 dependency.

Build

This has only be tested on Linux/x86_64. May run on other systems with the requirements above.

• If required, edit the qmake project file: any2col.pro
• qmake
• make

Usage

Typical usage

any2coloring -i input_picture.jpg -o output_picture.pdf -p palette.csv

any2coloring -i input_picture.jpg -s -o output_picture_soluce.pdf -p palette.csv

Options

Unless specified, sizes are given in millimeters.

Flag	Long Option	Argument	Description
-h	--help	none	print help and exits
-v	--version	none	print software version and exits
-p	--palette	palette.csv	file providing the colors used to index the pixel-art picture (mandatory option)
-i	--input	input.png	input file, can be any picture supported by CImg/G'MIC. If the file contains multiple pictures, like animated gif, only the first one is processed. (mandatory option)
-o	--output	output.pdf	output coloring as a PDF file
-k	--text-color	color	text color, expects an integer value from 0 to 255, rendered gray
-g	--line-color	color	line color, expects an integer value from 0 to 255, rendered gray
-x	--pixel-size	pixel size	the size of one pixel, as rendered on the pdf file
-w	--page-width	page width	defaults to A4 width (210 mm)
-f	--page-height	page height	defaults to A4 height (297 mm)
-t	--margin-top	top margin	minimal top margin, defaults to 5 mm. May be larger due to input file geometry
-b	--margin-bottom	bottom margin	minimal bottom margin, defaults to 5 mm. May be larger due to input file geometry
-l	--margin-left	left margin	minimal left margin, defaults to 5 mm. May be larger due to input file geometry
-r	--margin-right	right margin	minimal right margin, defaults to 5 mm. May be larger due to input file geometry
-c	--color-output	none	colored output (color labels are replaced by the color they actually represents)

Some parameters are hard-coded and may only be changed by recompiling the program. This includes:

• the thickness of the grid;
• the size of the text;
• the font.

Example

Original

European robin, picture adapted from mediawiki (Author: Charlesjsharp, license: CC BY-SA 3.0)

Processed pictures

Coloring page	Answer

(Both picture under license CC BY-SA 3.0)

Colored picture

(Picture under license CC BY-SA 3.0)