[Bf-committers] HiDPI notes for other OS'es

[Ton Roosendaal]

Hi,

As I explained before, I made MacBook retina to work for HiDPI in the least intrusive way for our code. But I also had to do it in a way it would work for everyone.

That meant I had to make two things work independently:

- DPI scaling for UIs in general.
- Apple's HiDPI implementation

Unfortunately these two features were not following an identical specification. That meant I had to seperate it in a Mac-only value (Pixelsize for now) and DPI.

For example, a retins "dot" is default set to be two pixels large. If you start Blender with 72 DPI, it will show visually the same button sizes whether you are in retina mode or not.

An important design decision from Apple was to decouple Desktop coordinates from pixels.
You can have retina desktops of 1024, 1440, 1920 "wide" which all get mapped to the actual 2880 screen pixels. But for each desktop width, a "dot" and standard line widths stay 2 pixels. Still following? :)

Mind boggling... especially if you draw the whole UI in OpenGL.

I'm still waiting for information how Linux or Windows will address HiDPI. Hopefully in the same way, but probably not...

-Ton-

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Ton Roosendaal  -  ton at blender.org   -   www.blender.org
Chairman Blender Foundation - Producer Blender Institute
Entrepotdok 57A  -  1018AD Amsterdam  -  The Netherlands