Slow scrolling in iPod music selection window in iTunes8

Question

Hi,
Since the update to iTunes 8 I've noticed that scrolling/dragging the scroll bar in the iPod Music selection window has become very very slow, to the point where clicking on the scroll bar and dragging it causes a CPU load spike on my Centrino vPro dual-core Lenovo T61 (4GB RAM 32-bit Windows) and very jerky responses.
This is only happening when selecting Music/Podcasts on both iPods. The Grid view/Coverflow etc is not showing ths behaviour.
This used to be smooth and quick - anyone else seeing this?
Tim

Answer 1

You are comparing apples and oranges - or further afield horses and carts.
The Portable Document Format is a rendered format. A layout engine has mapped character codes to glyph codes and the geometry of the line layout has been computed. What remains is to draw on the colour desktop display.
Apple Pages in layout mode and Microsoft Word in layout mode have to do the rendering, that is, map from character specifications to glyph shapings while composing ligatures in the line, decomposing ligatures at the end of the line and in tracked line layout, and much, much more.
It is proprietary information when Pages and Microsoft use which parts of the operating system to do what, and when they do whatever they do themselves. Nominally, there is ATSUI Apple Type Services for Unicode Imaging and there is CoreText.
Apple in its developer discussions is saying that ATSUI is slower than CoreText, by about fifty percent if memory serves. All of this again involves further parameter, namely whether the layout is by line or is by paragraph.
In the implementation of Apple TrueType 2 in 1994, the layout is by line hence the LLM Line Layout Manager. At that time, URW in Hamburg had an algorithm for paragraph level layout developed by Dr Peter Karow and Prof Hermann Zapf.
One of the reasons type developers gave for having hesitations about the composition model in Mac OS 7.5 in 1994 was that the layout was limited to the line level. Of course, so was QuarkXPress, PageMaker and every other application available at the time.
Anyway, OS X 10.4 and OS X 10.5 is still line level for speed, but if CoreText boosts rendering speed in OS X 10.6 it will also be possible to provide support for paragraph level layout (?). Alongside support for smart typographic scaling that is in the OS, but is not in Apple applications at this point.
hh