HTML is not the problem.

Light Table doesn't have any issues with large files, and is built on essentially the same stack (Electron + native HTML/JS/CSS for Atom vs Electron + ClojureScript compiled HTML/JS/CSS for Light Table).

Visual Studio Code doesn't have any issues with large files, and is also built on web technologies (no source available but I assume some variant of Electron + TypeScript?).

The problem is somewhere in Atom itself.

> Visual Studio Code

It is based on Visual Studio Online. Its text editor component is non-trivial and Microsoft spent a lot of money on it. The editor (codename "Monaco") is from Erich Gamma (ex-IBM/Rational), the "Design Patterns" book author from Switzerland. Microsoft bought the Monaco editor with him and its the single reason why TypeScript exists and why JavaScript ES6 looks like it looks ("class" syntax) and why he leads the Visual Studio team: http://en.wikipedia.org/wiki/Erich_Gamma

The Monaco editor (coded in TypeScript) will never be open source, its their competitive advantage. The same reason why HTML5's contentEditable API will never be fixed in IE/Chrome/Safari as a web office suite is their competitive advantage of Microsoft Office365 Web Word , Google Docs and Apple iCloud Pages. With a bug-free contentEditable API would render also Monaco editor and many other web based rich text editors obsolete: https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement...

> Visual Studio Code

Virtual lines in action.

1. Open VS Code with a file that extends below the bottom of your screen.

2. Press F12 to open the dev tools.

3. Use the magnifying glass to inspect the final visible line of code (it should be the predecessor sibling of <div class="contentWidgets">).

4. Scroll the text editor up and down and watch as the lines are added and removed from the HTML.

Edit: Looked at Atom and, yep, all the lines are kept in the HTML all the time. They seem to be chunked into "tiles" but those tiles always exist in the document.

Edit2: Actually it seems as though there only ever exist 3 tiles (partially obscured by top, fully visible, partially obscured by bottom) containing a dynamic list of lines. So this isn't why Atom is slow, arguably this is a better approach than appending/removing single lines at a time (which is what VSCode does).

I've actually done not 3D, but 2D animation in Powerpoint (as a kid, with access to an office suite, but not the internet and thereby more appropriate software). Each slide contains a frame of animation (drawn in Paint, of course), and slides advance automatically in milliseconds. You can attach an mp3 to play in the background for the soundtrack. Save it as a .pps and you have a cartoon that you can share with your friends.

That made me wonder whether the demoscene had ever done something with Powerpoint... and indeed it has:

http://www.pouet.net/prod.php?which=54670

http://www.pouet.net/prod.php?which=30319

Excel too:

http://www.pouet.net/prod.php?which=53021

Completely impractical and very silly, but that's what the demoscene is for...

Because of extensibility concerns and the sheer number of JavaScript developers? I'd agree if you say it's not a good compromise, but it is one nevertheless.

"Imagine if designers tried to do everything in PowerPoint for some unknown reason."

A fair percentage of the employees where I work seem to have reached that point already - reports, training material, data for general discussion, GANTT charts with individual symbols that I guess must be manually moved every week. Gah!