COcodetrotter·Apr 8, 2023
I am reminded also of Opera Mini back in the day. It did not stream the DOM, but they were rendering pages on their servers and then using fancy compression techniques to deliver the rendered page to your mobile phone. This was a godsend back in the bad old days of slow mobile phone internet.
I am talking about the Java ME application. Not the more recent browsers they’ve made.
> It was primarily designed for the Java ME platform, as a low-end sibling for Opera Mobile
> […]
> The functionality of the Mini mode is somewhat different from a conventional Web browser, with the amount of data which has to be transferred much reduced, but with some loss to functionality. Unlike straightforward web browsers, Opera Mini fetches all content through a proxy server, renders it using the Presto layout engine, and reformats web pages into a format mor
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e suitable for small screens. A page is compressed, then delivered to the phone in a markup language called Opera Binary Markup Language (OBML), which Opera Mini can interpret. According to Opera Software, the data compression makes transfer time about two to three times faster, and the pre-processing improves the display of web pages not designed for small screens.
https://en.wikipedia.org/wiki/Opera_Mini
Interestingly I found that someone has written a script to convert OBML to HTML. Their intended use-case for the script is to make pages saved with Opera Mini viewable in other browsers. But to me the main interest is that I would like some day to make something similar to Opera Mini on my own, and the README of the conversion script has some technical details about OBML.
> because OBML files are the output of Opera's HTML rendering engine, many elements are pixel-positioned according to the original device's screen size and font metrics. Because many J2ME devices had custom fonts (optimized for low-res screens), it's possible that your computer will show the same text as too-tall or too-wide, and lines may overlap.
> […]
> OBML does not have <a href=...>, i.e. you cannot actually have text that is also a link. Instead the engine outputs text and links as two separate layers – first it places the actual text at position (X,Y), then overlays it with "link" rectangles at position (X,Y,W,H).
> […]
> OBML does not have styled widgets the way HTML would. The style is actually pre-rendered, and those pretty 3D effects are made out of pixel-positioned lines and rectangles. Even button gradients are pre-rendered and drawn as a series of 1-pixel thin lines.
https://github.com/grawity/obml-parser