Suggested all-platform solution for "Support for Hi-DPI displays"
JavaFX 2.2 assumes that coordinates are specified in physical screen pixels. Given the broad variety of existing display resolutions, this necessitates laborious manual scaling of layout coordinates, based on DPI or default font size. Otherwise, applications that should run on more than one system risk appearing too large or too small, or even with defective layout when some parts are scaled while others are not. This is what currently happens on Windows, as I've demonstrated with some Oracle tutorials: http://news.kynosarges.org/2013/08/09/javafx-dpi-scaling/
JavaFX 8 introduces automatic coordinate scaling for Mac "Retina" HiDPI mode, but we really need this feature on all platforms. For example, a call such as Screen.setScale could set a scale of Screen.getDpi()/96 by default, and perhaps accept an argument for custom scaling. All coordinates subsequently specified in code, CSS, or FXML should be scaled accordingly, unless the program explicitly disables scaling at some point, e.g. to precisely draw bitmaps.
JavaFX 2.2 on Windows correctly picks up the DPI-scaled default font, correctly scales built-in controls around that font size, and also correctly reports the Screen.getDPI() value. What remains to be done is automatically scaling any explicitly specified coordinates, too, so as to avoid the clash between scaled and unscaled layout parts demonstrated in my linked post.
Note that Windows has supported DPI scaling in this fashion since Windows XP. I'm mentioning this because e.g. https://javafx-jira.kenai.com/browse/RT-27960 seems to assume that DPI scaling is new to Windows 8, but that's merely when this feature gained greater public awareness due to MS Surface Pro defaulting to 144 DPI.
Also note that Windows 8.1 will introduce a new relevant API, namely per-monitor DPI scaling. A global scaling solution for JavaFX should probably this into account and likewise maintain distinct DPI scaling for each screen, if supported by the OS.