[tomsmeding]

> Each time we draw a bit of graphical content to a scroll view, we first allocate the tiles necessary to display the corresponding visual area.

I get the intent here, to avoid the issue of not knowing how large a buffer to allocate for your scroll view in the first place. But doesn't this still use way too much memory? Especially for something like an irc client, the scroll view will only grow as the program is used longer, and as such the number of tiles of rendered content will also only grow. You'll of course need to keep the textual history in memory, but that's far smaller than the rendered screen contents.

Proper GUI toolkits (disclaimer: I have worked with few, and only a little at that) handle this, I think, by not considering the scroll view a canvas to draw stuff on, but instead a thing that you can place widgets on. Each widget has access to some data that allows it to re-draw its graphical content at some position on-screen, and the scroll view forgets rendered content far outside the visible area, and asks widgets to re-draw their content whenever they get scrolled onto the screen again.

Of course, you could expect requests for even more over-engineering ;)

Cool stuff! As someone else mentioned, you missed April 1st.

[codyd51]

Yes, you're absolutely correct! The design here totally suffers from unbounded memory use if you draw onto a large canvas. (Restating parts of your comment for confirmation that this is also how I think about it.)

To resolve this while maintaining the spirit of the design, I think two representations need to be kept: one for the rendered pixel data, and one 'out of band' representation (such as the textual data - you also highlighted this in your comment).

The idea is that, when the pixel buffer memory gets too large, some of it can be dropped. When it scrolls back into view again, it can be repopulated by the secondary representation. What I don't like about this is how it doesn't feel like it generalises well - you always need to be able to store the secondary representation, and have code to redraw it.

I think the concept you suggested is a really good one: just make sure everything that's drawn is its own 'encapsulated' widget with its own drawing logic, and you can ask it to render itself whenever that's convenient. I'm grateful for the input here, and think I will end up switching to this sort of approach in the future.

[tomsmeding]

I'm not sure "correct" engineering really fits UEFIRC, somehow :p

But if it's fun, go ahead! Perhaps it's helpful for axle too. :)