gd-icon-renderer

A (WIP) Crystal Geometry Dash icon renderer library, utilizing libvips

Why?

Server-side rendering of icons. This functionality doesn't need to be restricted to an HTTP server, so I figured I could just move it into a library.

Pre-requisites

You'll need to install libvips, alongside a devel package for building if available. Be sure to leave this note in the README of the application you're making too.

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     gd-icon-renderer:
       github: oatmealine/gd-icon-renderer
   

2. Run shards install

Usage

Currently, for most examples under examples/, you'll have to plug the icons folder of your GD install in data/. Otherwise, the process for rendering an icon is as follows:

1. Load spritesheets:

   # Replace the filepaths here with whatever is relevant for your usecase
   sheet = IconRenderer::Assets.load_spritesheet("data/icons/ship_44-uhd.plist")
   

2. Render the icon out:

   icon_img = IconRenderer::Renderer.render_icon("ship_44", [0.0, 0.0, 0.0, 1.0], [255/255, 125/255, 125/255, 1.0], nil, true, sheet)
   

   You'll now be given a Vips::Image.

3. (Optional) You might find it useful to now trim the whitespace out, as Geometry Dash icons usually have lots of surrounding blank space:

   alpha = icon_img.extract_band(3)
   left, top, width, height = alpha.find_trim(threshold: 0, background: [0])
   icon_img = icon_img.crop(left, top, width, height)
   

4. You'll most likely want to save the resulting image somewhere:

   icon_img.write_to_file("icon_rendered.png")