Nitrogen Fingers Paint

File Format
Name	Nitrogen Fingers Paint
Ontology	Electronic File Formats Graphics Nitrogen Fingers Paint
Extension(s)	.nfp
Compression	None
Reference Implementation	CC:T's paintutils (lua)
Error Resilience	None

Nitrogen Fingers Paint (NFP) is a simple text file format used by ComputerCraft to store images.

CraftOS's paint program allows for easy editing of these files with a GUI.

Format

An NFP file consists of a text file containing a hex character for each pixel.

Each pixel's character must be in the range 0-f and be lowercase, any other characters (including capital A-F) are treated as fully transparent pixels.

The newline (\n) character moves to the beginning of the next row.^{[End file with newline or not?]} Due to the nature of this, it is possible to have rows of different length and therefore means that nonsquare images can be created.

Whilst any unrecognised character is treated as a transparent pixel, it is recommended that a space be used. CraftOS's paint program automatically converts all transparent pixels to a space when saved.

Colours

To calculate a colour for a given value do 2x and then treat it as a 24-bit RGB value (8 bits for each of red, green and blue).

It is recommended that a lookup table be generated for performance.

Pixel aspect ratio

CraftOS's paintutils library (and therefore paint) uses character mode for displaying images, meaning one image "pixel" is a character cell. Character cells are at a 2:3 aspect ratio, 12×18 real pixels in size.

Example

house.nfp

represents a transparent pixel.

NFP	PNG	PNG (nonsquare)
c␤ eeeeec␤ eeeeeee␤ eeeeeeeee␤ ccccccc␤ c33cc5c␤ ccccc5c␤ fffffffffff␤

External links

• ComputerCraft:Tweaked's CraftOS paintutils Implementation (lua)

  Note: Lua lists start at 1 so 2x-1 is used when generating the lookup table.

• ComputerCraft:Tweaked Wiki's Colour table (Paint/Blit column)
• CraftOS-Standards (Poorly documented)