Recently I tried once more to read a pdf file on n900. And as usual, it worked bad. Not only because of small screen – that particular pdf had two-column formatting, and n900′s screen is wide enough to display one of these two columns with a readable font. Much worse was extremely slow redrawing.
Finger scrolling on a touch screen is cool – but only if system has enough power to immediately show content as it is scrolled to be visible. In practice I try to scroll with finger, then a second or two pass, then page on the screen starts to move, replaying all my finger movement during that second or two (which was not very direct because of no quick visual feedback), by the way text at borders goes out of screen for a moment, and that area becomes broken and is redrawn only after several more seconds. And then, in less than a minute (after reading displayed content), all that has to be repeated. In total, this makes UI almost unusable.
While looking at this, I thought – why not use GPU here? This device has a powerful GPU, enough even for non-trivial games. So why not convert a pdf page into a scene description for GPU, and then get zero-delay scrolling and scaling at least?
This could be useful even on desktops – sometimes pdf viewers do have interactivity problems, especially at very-large scale (400% or more) which is needed to view board schematics diagrams.
Anyone ever implemented this? Or maybe wants to implement?.. 
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