Posted on 2/13/2022
Tags: Programming, Art
I recently needed to make pixel art for a game and wanted to define the images in code rather than having separate image asset files.

Defining the images in code comes with some benefits:
- I don't need separate versions of the images for different resolutions. I can easily scale them up automatically.
- I can easily slice the sprites to animate them programmatically
- I can make minor tweaks with a text editor (my tool of choice! I am much more at home in a text editor than image editing software)
- I get useful diffs when changing images in source control

To achieve this, I created a simple format I'm calling "PCEImage" (which is short for "Pixel-Character Encoded Image"). Here's what it looks like:


Here's that image as a PNG (drawn with scale 10):
A neat benefit of this encoding is that the images are also ASCII art -- it's easy to see what a PCEImage looks like even without coloring. In fact, this format is a combination of ASCII art and indexed color.

PCEImage Format Specification

The first section of a PCEImage defines what color each character represents. Each line in this section looks like: CHARACTER:HEXCOLOR
Then there's one blank line.
Then the second section is the image itself. Every character in this section (except for the newline at the end of each line) represents a pixel in the image. Every line in this section should be the same length (the width of the image).
There should not be a newline character after the last pixel character on the last line.

PCEImage Reference Implementation

I wrote a reference implementation of this specification in JavaScript here.

I had a little fun and also added a wobble mode (similar to Wobblepaint, mentioned in my PICO-8 post).

See it in action in my PCEImage Editor.

Read more about the editor here.