What should I do about the display content area of the image?

It is difficult to understand the stretch area of the image at. What is the display content area?
. 9 is a special image format in the application software development of the andriod platform. The file extension is .9.png.

The smart phone has the automatic horizontal screen function. The same interface will change the display direction with the parameter of the direction sensor in the mobile phone (or tablet). After the interface changes the direction, the image on the interface is stretched due to the variation of the length and width, resulting in distortion and deformation of the image.
We all know that the Android platform has a variety of different resolutions. After the cut image files of many controls are enlarged and stretched, the corners are blurred and distorted.
OK. Using the PNG technology on the Android platform, you can stretch the image horizontally and vertically at the same time to achieve a perfect Display Effect in multiple resolutions.

For example:

Use the draw9patch tool in SDK tools to open an image.

Click Show patches. The pink area is the area to be stretched.

Click Show content. The blue shadow area on the right is the content display area.

As shown in the figure, the content display area is on the top left of the image. How can it be easier to understand?

If the image is used as the background of the button, the text of the button is "give a try ",

The display status of this button should be:

The text of the button is not displayed across the shadow part.