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: http://stackoverflow.com/questions/8785643/what-exactly-is-device-pixel-ratio — user1835565, Jul 31 '14 at 12:13
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, Jul 31 '14 at 12:14
@Jongware thanks! How about the `device independent pixels`, is it something similar to logical pixel? — Blake, Jul 31 '14 at 12:19
@Jongware LOL, I got it from http://msdn.microsoft.com/en-us/library/windows/desktop/ff684173(v=vs.85).aspx , and I still don't quite get it after reading the article... — Blake, Jul 31 '14 at 13:02

score 10 · Answer 1 · edited Jan 12 '18 at 05:35

10

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.

edited Jan 12 '18 at 05:35

Kennet Celeste

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answered Jul 31 '14 at 12:13

Luca Detomi

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score 4 · Answer 2 · answered Mar 07 '15 at 13:40

4

You can take a look at the site below:

http://www.iosres.com

For iPhone 4s logical screen resolution is half of the actual resolution (not include in the site above).

answered Mar 07 '15 at 13:40

Vas Giatilis

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more Apple models are available if you click on **`Filter > All`** – Hamza Rashid Oct 23 '17 at 16:35

score 0 · Answer 3 · answered Jun 16 '23 at 23:55

This article refers to what you call logical pixels as points on iPhone and independent pixels (DP) on Android.

It provides formulas on how to convert logical pixels to physical ones.

iOS:

physical pixels = points * DPI / 163

Android:

physical pixels = independent pixels * DPI / 163

DPI (aka PPI) is a Dot Per Inch or Pixel Per Inch is the number of physical pixels per inch.

Physical screen resolution and PPI can be easily obtained from sites like GSMArena. But as developers, we are more interested in logical resolution, and especially logical width.

Let's calculate the logical width for iPhone 14. Its physical resolution and PPI are 1170 x 2532 and 460 respectively:

logical width = 1170 * 163 / 460 = 415

For Samsung S23 (1440 x 3088 and 500 ppi):

logical width = 1440 * 160 / 500 = 460

For iPhone 5 (640 x 1136 and 326)

 logical width = 640 * 163 / 326 = 320

what is display's logical resolution?

3 Answers3