what is display's logical resolution?

Question

I encountered this concept: device pixel ration, some said it is the ratio between physical pixels and logical pixels.

For example iPhone has:

Physical resolution: 960 x 640
Logical resolution: 480 x 320

so does it mean that the height of each physical pixel is the screen height/960 ? And the height of each logical pixel is equal to twice the height of the Physical pixel?

On that post, they say the opposite: stackoverflow.com/questions/8785643/… — user1835565
The problem is those pesky new high resolution screens -- or, rather, legacy web pages (and to a lesser extent, applications) that specify positions and sizes in px pixels. When taken literally, every web page would appear way too small. So Apple invented the "logical pixel" measurement unit, whereas "physical pixels" are the ones you would see. (If only they weren't so darn small.) — Jongware
@Jongware thanks! How about the device independent pixels, is it something similar to logical pixel? — Blake
@Jongware LOL, I got it from msdn.microsoft.com/en-us/library/windows/desktop/… , and I still don't quite get it after reading the article... — Blake

Luca Detomi Luca Detomi · Accepted Answer · 2014-07-31T12:13:46

We can say that 4 physical pixels make 1 logical pixel ;-)

In other words: most recent retina displays have much more pixels than original iPhone, but to maintain compatibility and "visual size" software use 4 physical pixel to render a unique logical pixel.

what is display's logical resolution?

2 Answers