How do you calculate the size of a loaded image

Issue

I have a an image image.png in the drawable folder (not any of the other drawable-hdpi, etc. folders).

This image's size is 50x50. But when I load it from my application like so: BitmapFactory.decodeResource(getResources(), R.drawable.image)

and then I check the size with getWidth() and getHeight(), I get 150x150.

Can anyone please explain how to calculate this 150x150 loaded size? (Not programmatically, I just want to know if there's a formula I could have used to tell that the image would be loaded to 150x150)

Also, is this 150x150 in pixels?

Thanks!

Solution

• Yes, the value is in pixel unit, make use of the java doc my friend~
• If you want the image size to stay unchanged, put it into drawable-nodpi
• If you put the image in the drawable, it is the same as in the drawable-mdpi, as the first Android-powered device, the T-Mobile G1 is a normal size and mdpi (medium) density :)

• And the no magic formula :

  ldpi (low) ~120dpi
  mdpi (medium) ~160dpi
  hdpi (high) ~240dpi
  xhdpi (extra-high) ~320dpi
  xxhdpi (extra-extra-high) ~480dpi
  xxxhdpi (extra-extra-extra-high) ~640dpi
  

  That is, in your case, likely developing on a xxhdpi device, 480/160*50=150, remember android is designed to be visualize all the ui elements at the same size on all screens, so the higher density , the larger scaled image .

Answered By - Neil