Question/feedback regarding Windows Hi DPI support and how it will affect applications

Werner Lehmann lehmann at
Wed Feb 18 10:13:16 UTC 2015

Hi Jim,

interesting read. I guess I learned more about the topic than I can 
help. Also found this resource interesting:

Some thoughts. Obviously it is less desirable to require every 
application to do their own scaling. I can't imagine that this would 
work on a larger basis. As to the question of integer vs float 
coordinates, there is a lot of snapToPixel stuff going on. And one of 
the reasons is to get crisp pixel-aligned lines. Snapping to logical 
coordinates could then snap to non-integer physical coordinates (if the 
scaling factor is 125% or somesuch). Which may be ok if hidpi makes up 
for it...

As to em-based styling, I was under the impression that there was a 
constant factor for 1em. Reading section "RESIZING FOR DIFFERENT SCREEN 
DPI" in modena.css I am not so sure anymore. The resource above also is 
unsure (FWIW):

"JavaFX em handling is inconsistent, sometimes referring to the 
automatically acquired system font but at other times yielding a 
hard-coded default size."

Finally, it would be nice to get information about the actual screen 
DPI. In my tests Screen.getDpi always returns 96, regardless of what it 
actually is...


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