9patch 在server端應用過程

two kinds 9patch：

There are two types of ninepatch file formats in the Android world ("source" and "compiled"). The source version is where you add the 1px transparency border everywhere-- when you compile your app into a .apk later, aapt will convert your *.9.png files to the binary format that Android expects. This is where the png file gets its "chunk" metadata. (read more)

client code：

InputStream stream = .. //whatever
Bitmap bitmap = BitmapFactory.decodeStream(stream);
byte[] chunk = bitmap.getNinePatchChunk(); //讀chunk[]
boolean result = NinePatch.isNinePatchChunk(chunk); //判斷是否是編譯後的9Patch
NinePatchDrawable patchy = new NinePatchDrawable(bitmap, chunk, new Rect(), //由流創建9Patch圖片

Server-side:

      you need to prepare your images. You can use the Android Binary Resource Compiler. This automates some of the pain away from creating a new Android project just to compile some *.9.png files into the Android native format. If you were to do this manually, you would essentially make a project and throw in some *.9.png files ("source" files), compile everything into the .apk format, unzip the .apk file, then find the *.9.png file, and that's the one you send to your clients.

tips:

相關源碼在android源碼的aapt目錄下

 If you really, really need to construct your own chunk byte array, I would start by looking atdo_9patch, isNinePatchChunk, Res_png_9patch and Res_png_9patch::serialize() in ResourceTypes.cpp. There's also a home-made npTc chunk reader from Dmitry Skiba. I can't post links, so if someone can edit my answer that would be cool.