Documention for: oneliner-image-to-ppm.r
Created by: vincentecuye
 on: 29-Jan-2013
Last updated by: vincentecuye on: 29-Jan-2013
Format: text/editable
Downloaded on: 30-Apr-2025

oneliner-image-to-ppm.r
    Author: Vincent Ecuyer
    Date: 30-Jan-2013

===Purpose

Short code to save an image! as a color image in PPM binary (P6) format. It's mostly useful for interacting with the Netpbm tools. No alpha information is saved, use 'alpha-to-pgm too (in one-liner-image-to-pgm.r) if you need it.

===Usage

    to-ppm value (image!)

===Example

REBOL 2:
    write/binary %imageTest.ppm to-ppm make image! [320x256 255.0.0] 

REBOL3 always write in binary, so:
    write %imageTest.ppm to-ppm make image! [320x256 255.0.0]

===Commented Code

    to-ppm: func [
        "Converts an image to a PPM binary file format"
        value [image!] "Image source"
    ] [
        ; equivalent to "to-binary rejoin" : we want a binary! resul
        join #{} [

            ; the binary PPM file header, followed by a <space>
            "P6 " 

            ; the image size, in the form width <space> height
            replace form value/size "x" " " 

            ; a <space>, the max component value, and a <newline>
            " 255^(0A)" 

            : the image data as RGB bytes sequences
            value/rgb
        ]
    ]