Several questions about QMLWeb architecture.

[rafal-tarnow]

Hi, I'm very interested in the project (it's a pity it's not actively developed). I have a question regarding the rendering backend. What do you use in the project? Does QmlWeb use canvas for rendering buttons, images, etc.? Or is it done differently? Another thing, would transitioning from a rendering backend to Three.js (based on WebGL) be a challenging task for this project? (I am a C/C++ programmer, I have very little knowledge of web technologies.)

[Plaristote]

There is no rendering backend ! We took the path of least resistance, which was probably best in terms of performances as well. QMLWeb is just plain DOM, CSS and JavaScript. No canvas involved. QMLWeb doesn't really render stuff: rather it serves as a layer between QML and the DOM API.

The history of the project is important there. Two things have changed since the beginnings:

• QtQuick.Controls was replaced with QtQuick.Controls 2, which had a more complete approach. There were many equivalent between Controls 1 and what the DOM API provides. Controls 2 took things a step forward, and I've been unable to implement most of it: it's a huge amount of work compared to what Controls 1 would've required.

• CSS has evolved plenty, with the introduction of flex, grid, and animations. Back when this project started, these things were hard to do using the technologies natively provided by the web browser. You'd need a lot of JavaScript to implement such behaviours. QMLWeb was a way to implement such features easily in the browser using an already defined language.

Basically, QMLWeb is a lot less relevant than it was 10 years ago, both from the perspective of compatibility with QML and providing features that web browsers don't. It could still be relevant, had we a complete implementation of Controls 2... but our team never got to that. I made an attempt at it a couple of years ago, on my own, but it's a lot of work, and without eyes behind my back to check out my work and discuss my decisions, I feel like I might be wasting a lot of time over something that might never be worth it.

Feel free to ask anything else.