deloptes composed on 2016-12-02 19:56 (UTC+0100):
When you have a physical display lets say 21" diagonal. This gives you particular dimensions. Look here https://en.wikipedia.org/wiki/Display_size#Display_sizes_of_common_TVs_and_c...
And this also gives you a specific set of pixels supported. Changing DPI changes how many pixels are involved in displaying whatever you want to display.
I have my own site for those sorts of things: http://fm.no-ip.com/PC/displays.html http://fm.no-ip.com/PC/dpi.xhtml http://fm.no-ip.com/Auth/Font/fonts-pt2px-tabled.html http://fm.no-ip.com/Auth/Font/fonts-pt2px.html and more: http://fm.no-ip.com/Auth/wauth1.html