android:scaleX

added in API Level 11

scale of the view in the x direction.
A scaleX of 1 means no scaling is applied.

Ensure to change the minSDKVersion to 11, or greater.

       android:scaleX = ".5"

Related Articles:

Resources:
http://developer.android.com/reference/android/view/View.html#attr_android:scaleX
http://developer.android.com/reference/android/R.attr.html#scaleX