addyosmani / robinson

A toy web rendering engine

Robinson

A toy web rendering engine written in the Rust language, by Matt Brubeck ([email protected]).

I'm writing this code purely for educational purposes. My goal is to create an incomplete but extremely simple engine as a way to learn more about basic implementation techniques, without worrying about complications like:

• Real-world usability
• Standards compliance
• Performance and efficiency
• Interoperability

These are all important goals, but there are other projects working on them. By ignoring them completely, this project can focus on being as simple and easy-to-understand as possible.

Why create a simple—but useless—toy rendering engine? Mostly because I personally want to learn how to do it. If I succeed, I also hope that other people can learn from my code by reading or modifying it, or learn from my experience as they set out to build their own toy browser engines.

For more details see Let's build a browser engine!, a series of how-to articles based on this project.

Status

Currently implemented:

• Parse a small subset of HTML and build a DOM tree.
• Parse a small subset of CSS.
• Perform selector matching to apply styles to elements.
• Basic block layout.

Coming soon, I hope:

• Inline layout.
• Paint text and boxes.
• Load resources from network or filesystem.

Instructions

1. Install Cargo and Rust.

2. Clone the robinson source code from https://github.com/mbrubeck/robinson

3. Run cargo build to build robinson, and cargo run to run it.

By default, robinson will load test.html and test.css from the examples directory. You can use the --html and --css arguments to the robinson executable to change the input files:

./target/robinson --html file.html --css file.css

The rendered page will be saved to a file named output.png. To change the output filename, use the -o option.