How does density value calculate in android

Question

Can anybody explain me what formula android use to calculate screen density?

score 39 · Accepted Answer · edited Oct 03 '14 at 04:18

39

Density can be calculated by the following formula:

Density = sqrt((wp * wp) + (hp * hp)) / di

Where:

wp is width resolution in pixels,

hp is height resolution in pixels, and

di is diagonal size in inches.

edited Oct 03 '14 at 04:18

C0deH4cker

answered Feb 24 '11 at 11:37

Hari Kumar

7

This formula actully for [ppi](http://en.wikipedia.org/wiki/Pixel_density) but android likes the term `dpi` instead. Difference can be read [here](http://www.andrewdaceyphotography.com/articles/dpi/) – Fredrick Gauss Oct 14 '13 at 17:01
what is diagonal size in inches? – Mahdi Aug 22 '16 at 06:42
the distance between two opposite edges of a phone is called diagonal size. – AmiNadimi Sep 17 '16 at 12:48
Don't forget to divide bij 160 afterwards – Hibbem Jun 24 '19 at 09:25

score 6 · Answer 2 · answered Feb 09 '11 at 08:23

6

The formula is actual-dpi / 160. (Everything is scaled to 160 dpi.)

answered Feb 09 '11 at 08:23

Ted Hopp

2

Thanks for respond, Ted. But what is actual value? – teoREtik Feb 09 '11 at 08:30

Labeeb Panampullan · Answer 3 · 2011-02-09T08:54:41.800

1

int pixel = 120;
final float scale = getResources().getDisplayMetrics().density;
int dip = (int) (pixel* scale + 0.5f);

Refer this following links

edited Feb 09 '11 at 08:54

answered Feb 09 '11 at 08:38

Thanks a lot, but i have to repeat my question again. I want to know how does OS Android calculate density. In your code snippet it is scale value. – teoREtik Feb 09 '11 at 08:45
I read a documentation about density, but I didn`t understand it completely. So I want to know, how does it calculate. That`s why I established this question – teoREtik Feb 09 '11 at 09:23
2

I think you need to rephrase your question. Explain a little more what you want to accomplish. Android's concept of density is the ratio of actual number of pixels/inch to the default pixel density of 160 pixels per inch. Take a look at the [DisplayMetrics](http://developer.android.com/reference/android/util/DisplayMetrics.html) class docs. – Ted Hopp Feb 10 '11 at 04:39

score 0 · Answer 4 · answered Aug 17 '19 at 08:15

0

To calculate screen density, you can use this equation:

Screen density = Screen width (or height) in pixels / Screen width (or height) in inches

answered Aug 17 '19 at 08:15

sandes

4 Answers4