mirror of
https://github.com/mbirth/wiki.git
synced 2024-12-27 23:24:06 +00:00
118 lines
3.2 KiB
Markdown
118 lines
3.2 KiB
Markdown
|
---
|
||
|
|
title: Display density on Android
|
||
|
|
language: en
|
||
|
|
layout: default
|
||
|
|
created: 2015-12-02 17:19:42 +0200
|
||
|
|
updated: 2015-12-02 17:19:42 +0200
|
||
|
|
toc: false
|
||
|
|
tags:
|
||
|
|
- know-how
|
||
|
|
- hacking
|
||
|
|
- android
|
||
|
|
- display
|
||
|
|
- resolution
|
||
|
|
- lcd
|
||
|
|
---
|
||
|
|
Methods
|
||
|
|
=======
|
||
|
|
|
||
|
|
Android supports changing the display resolution in 2 different ways.
|
||
|
|
|
||
|
|
wm density
|
||
|
|
----------
|
||
|
|
|
||
|
|
This method works without root and changes the density of the *window manager*.
|
||
|
|
You can call this command only from the adb shell.
|
||
|
|
|
||
|
|
The syntax is:
|
||
|
|
|
||
|
|
wm density [ppi]
|
||
|
|
|
||
|
|
E.g. the Nexus 9 has a real display density of 288ppi, so you would run:
|
||
|
|
|
||
|
|
wm density 288
|
||
|
|
|
||
|
|
To reset the value to the factory setting (for the N9 that is 320), just run:
|
||
|
|
|
||
|
|
wm density reset
|
||
|
|
|
||
|
|
|
||
|
|
build.prop
|
||
|
|
----------
|
||
|
|
|
||
|
|
The other way to change the display density is to edit the `build.prop`. This
|
||
|
|
only works with root access.
|
||
|
|
|
||
|
|
To edit the file, first make the `system` partition writable by remounting it.
|
||
|
|
|
||
|
|
Then find the file `/system/build.prop` and open it in a text editor. I use
|
||
|
|
my favourite file manager [FX File Explorer](https://play.google.com/store/apps/details?id=nextapp.fx)
|
||
|
|
with its integrated editor for that.
|
||
|
|
|
||
|
|
Find the following line (Example from Nexus 9 with currently 320ppi):
|
||
|
|
|
||
|
|
ro.sf.lcd_density=320
|
||
|
|
|
||
|
|
And change the number to your desired value. BE SURE TO NOT CHANGE ANYTHING ELSE.
|
||
|
|
Save the file and reboot your device.
|
||
|
|
|
||
|
|
|
||
|
|
Advantages
|
||
|
|
==========
|
||
|
|
|
||
|
|
Setting the correct density value makes the display appear sharper and it may
|
||
|
|
even make your device run better.
|
||
|
|
|
||
|
|
Android knows different *densities* and if an app supplies graphics in different
|
||
|
|
qualities, it loads them according to the detected density. This means: The
|
||
|
|
higher the density, the larger graphics Android has to load and keep in
|
||
|
|
memory. So reducing the density (to the real value) can make Android load
|
||
|
|
a bit less detailed graphics and thus save RAM.
|
||
|
|
|
||
|
|
Android knows these quality classes:
|
||
|
|
|
||
|
|
| Class | PPI |
|
||
|
|
|------:|:-------:|
|
||
|
|
| ldpi | 100-140 |
|
||
|
|
| mdpi | 141-199 |
|
||
|
|
| hdpi | 200-319 |
|
||
|
|
| xhdpi | 320-340 |
|
||
|
|
| xxhdpi| ~480 |
|
||
|
|
|xxxhdpi| ~640 |
|
||
|
|
|
||
|
|
As you can see, the 320ppi of the Nexus 9 makes Android use *xhdpi* resources.
|
||
|
|
If you change the density to 318, you won't notice anything, but Android will
|
||
|
|
suddenly use the *hdpi* resources and save memory when running apps.
|
||
|
|
|
||
|
|
|
||
|
|
Problems
|
||
|
|
========
|
||
|
|
|
||
|
|
If you don't have root access and try to change the density using the `wm density`
|
||
|
|
command only, it might seem to work on the first glance, but you will notice
|
||
|
|
strange effects.
|
||
|
|
|
||
|
|
If you're using SwiftKey, you'll notice it right away:
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
Other problems are more subtle (Nexus 9 at 288ppi):
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
Compare this to the same screen at the original 320ppi:
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
(If you're still searching: Notice the huge "chevron" icon after the
|
||
|
|
developer's name. And also the **huge** background image.)
|
||
|
|
|
||
|
|
<p><div class="noteimportant" markdown="1">
|
||
|
|
These problems only occur if you use only one method to change the density. If
|
||
|
|
you use **both** methods and set them to the same value, everything will look
|
||
|
|
just fine.
|
||
|
|
</div></p>
|
||
|
|
|
||
|
|
More info at the [xda forum](http://forum.xda-developers.com/nexus-9/general/guide-little-trick-improvimg-nexus-9-t3224931).
|