Re: Best way to do static overlay over scrolling content?
Re: Best way to do static overlay over scrolling content?
- Subject: Re: Best way to do static overlay over scrolling content?
- From: "Gary L. Wade" <email@hidden>
- Date: Wed, 20 Jul 2011 07:11:52 -0700
You may be better served to consider doing something like the way rulers are used in relation to a scroll view. If you choose an overlay that needs to keep synchronized with another view, look at how WebKit does this for its Inspect Element feature.
- Gary L. Wade (Sent from my iPhone)
On Jul 20, 2011, at 12:55 AM, Daniel Vollmer <email@hidden> wrote:
> Hello,
>
> I have a visualisation application that displays multiple graphs (currently using NSCollectionView, but possibly switching to an NSView-based NSTableView in the future) that looks like this: http://www.maven.de/code/wowplot/example_chains.png
>
> When you scroll sideways, the "title" of each graph stays in place, whereas the rest of the content scrolls as usual. Currently, I simply redraw the whole graph (well, the visible bit). This strikes me as rather inefficient, because I essentially need to redraw the complete visible portion onScroll instead of only the freshly revealed bit.
> There are some things I can think of, but I'm unsure on which would be the most appropriate way:
> - Put an NSTextLabel inside the NSScrollView's contentView and dynamically reposition it into the visibleRect.
> - Add a largely transparent subview to the NSScrollView (so it's the same size as the visible portion) and draw all titles in there, transforming coordinates as needed.
>
> Preferably, the compositing would only happen once when the visibleRect changes, not each frame (so the transparent blend doesn't each too much graphics memory bandwidth).
>
> Has anyone got any experience with this or suggestions on which way would be most appropriate?
>
> Thanks,
> Daniel.
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