5K retina & HiDPI

Discussion in 'iMac' started by nicwilson, Dec 29, 2014.

  1. nicwilson macrumors newbie

    May 28, 2010

    I am asking this question out of pure interest, being a technician a very long time I like to understand how things work and so far this partially escapes me. From past experience I have found this site seems to have answers to questions. ;)

    Having been playing with my new 5K Retina iMac for about a week now I have been mainly impressed with it, especially the way it handles hi-res screen and normal desktop use which brings me to my question.

    Can anyone explain how HiDPI works technically? The reason I ask this is I thought I knew but the following sparked my curiosity to check.

    My 5K iMac is in Best (retina) mode, so desktop looks as if its 2560x1440 and looks very nice in this mode, very usable and quite fast.

    If I do a screenshot, the resulting image is 5120x2880 so full 5K res as expected, however if I use various remote access apps they it display as 2560x1440 and work well so you would not know otherwise. This I suppose was unexpected unless I have misunderstood something.

    Going by info I had found it was basically described as 5K res with desktop UI, widgets, icons etc scaled 200%, so I was surprised to see the all remote access display as 2560x1440, so HiDPI is obviously catering for this too. This is great no complaints, an makes it easy to access from a lower res machine at work, it was just unexpected. This left me puzzled as to how it works, so I thought I would ask


  2. redheeler macrumors 604


    Oct 17, 2014
    HiDPI still operates off a standard pixel grid where one pixel on the grid equals four actual pixels. Therefore, images and text appear the same size as they would on a non-retina, but are actually rendered at twice the size.
  3. leman macrumors G3

    Oct 14, 2008

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