DPI

Introduction

We try to synchronize the DPI from the client to the server, so that applications will render with the correct settings and "look right" on the client. This may affect fonts, window sizes, cursors sizes, etc.

Caveats:

• support varies greatly depending on the operating system and version, desktop environment, number of monitors attached and their resolution, etc
• DPI support is much improved in version 0.16
• with X11, there are far too many places where the DPI can be looked up, many places where it can be overriden
• for virtualized "hardware DPI" which some applications calculate from the virtual monitor dimensions, you will need a patched wiki/Xdummy driver and wiki/FakeXinerama
• many applications will not reload the DPI settings, so they must be started after the client connects to get the correct DPI value

Links

• ​Of DPIs, desktops, and toolkits
• win32 API:
  • ​WM_DPICHANGED
  • ​GetDpiForMonitor
  • ​SetProcessDpiAwareness
  • ​Writing DPI-Aware Desktop and Win32 Applications
• ​Scaling Windows - The DPI Arms Race, in particular: ​Windows 8.1 - More DPI Changes
• ​About High Resolution for OS X
• ​Qt: Retina display support for Mac OS, iOS and X11
• ​xserver forces 96 DPI on randr-1.2-capable drivers, overriding correct autodetection
• ​please add option to avoid forcing of 96dpi

Related xpra tickets

• #697 gtk screen dimension detection is broken with high dpi displays on windows7 and later
• #163 pass client DPI preference to server (and use sane defaults of 96dpi)
• #976 client display scaling
• #919 frame extents synchronization

Data

TODO!