Button's 9-patch bitmap resolution

[Pantelis]

I want to make a 9-patch image for one button. What is the right resolution in pixel for that image?

Acording to this link
9-Patch Image – Designers Vs Developers - shubhayu.com

9-patch images can scale up but not scale down. Scaling down results in visual artifacts.
Always design for the smallest size possible. This will increase its re-usability.
...
Do not use a 9-patch image that is bigger than your View.

So, if a have a 40/40dip button, the right size in pixels for the 9-patch image must be defined having in mind a device with scale 1 in order to have the smallest size possible and so 40/40 pixels?

 

[thedesolatesoul]

Scale can be 0.75

 

[Pantelis]

Thank you thedesolatesoul.

So, i guess the above logic is correct? Isn't it?
9-patch image must be as small as possible? And in scale 1, one dip is equal to one pixel?

 

[thedesolatesoul]

I guess so. Do test on a 0.75 device though (thats the one I am unsure of).
The 9patch i have done so far have a fixed border and not much to stretch in the middle so they look okay.
I am not sure how yours look like.

 

[Pantelis]

OK. I will try that. Thank you.