An exciting technology has been gaining attention among developers recently. It's an animation technique that moves like a GIF but is actually an SVG file. This technology, introduced by Vincent D. Warmerdam, is truly revolutionary in that it can create surprisingly high-resolution moving images with just 256KB of file size.
Limitations of Traditional GIFs and Advantages of SVG Animation
Traditionally, developers used GIF files to visually demonstrate terminal workflows. However, GIFs have several critical drawbacks. First, they have large file sizes. Second, their resolution is limited. Third, they have constraints in color representation.
SVG-based animations elegantly solve these problems. Being vector-based, they don't pixelate when scaled up, text remains selectable, and file sizes are much smaller. The fact that they're directly supported in GitHub's README.md files is particularly appealing to developers.
Implementation Method: asciinema and svg-term-cli
There are two key tools for implementing this technology. First, record terminal sessions with `asciinema`, then convert them to SVG files using `svg-term-cli`.
asciinema rec a.cast //Perform desired tasks in terminal, then exit with ctrl-d cat a.cast | svg-term --out=a.svg
This process is surprisingly simple. asciinema records all terminal input and output with timestamps, then svg-term-cli converts this into SVG animation. The result can be added directly to README files with drag and drop.
The fact that SVG supports animation is itself a new discovery for many developers. However, animation capabilities have been included in the SVG specification from the beginning.
The core elements of SVG animation include:
- `animate `: Changes individual properties over time
- `animateTransform `: Animates transformations like rotation, scaling, and translation
- `animateMotion `: Moves elements along specific paths
svg-term-cli leverages these built-in SVG animation features to replay terminal output chronologically. It precisely calculates the timing of each character's output and converts it into SVG animation.
Real-World Use Cases
Vincent mentions extensively using this technology in his project called bespoken. Indeed, this approach is extremely useful in various situations.
For example, when explaining how to use CLI tools, developers previously had to take multiple screenshots or create complex GIFs. Now they can record actual terminal sessions and convert them directly to SVG. Users can copy actual commands and see all details in high resolution.
A New Standard for Development Documentation
This technology is particularly noteworthy because it can fundamentally change how we document development processes. Instead of static code examples or screenshots, we can vividly show actual execution processes.
Furthermore, direct GitHub support is tremendously helpful for open-source projects. If users can see working demos directly in README files, their understanding and engagement will significantly increase.
Technical Considerations and Limitations
Of course, this technology has some considerations. First, browser compatibility - not all browsers perfectly support SVG animations. Second, for complex terminal output, SVG files can still be large.
However, even considering these limitations, the benefits this technology provides are far greater. Particularly in the developer community, this approach is already spreading rapidly.
Future Prospects and Expansion Possibilities
This technology shows broader application possibilities beyond simple terminal recording. For example, code editor workflows or web application usage could be recorded in similar ways.
Considering SVG's extensibility, adding interactive elements is also possible. Features could be implemented where clicking specific parts shows detailed command explanations or links to related documentation.
In conclusion, SVG-based terminal animation presents a new paradigm for development documentation. This technology, which combines high quality, small file sizes, and GitHub support, will likely be adopted by more projects in the future. It's definitely worth trying for any developer.