What should i use for better performance, nine-patch or drawable xml resource?

android, android-drawable, nine-patch, performance, xml-drawable

Solution

My guess is, `NinePatch` would be slightly faster in most cases. Here's what I found.

`GradientDrawable` (the one used for rects in xml) uses this code to call through to `Canvas` which in turn uses native call leading to `SkCanvas`, `SkDraw` and eventually `SkScan` and `SkBlitter`.

On the other hand, `NinePatch`'s draw() has almost zero Java code before the native call to `NinePatch.cpp` which shortly calls `NinePatchImpl.cpp` -- `NinePatch_draw()` --- and that's where the magic is. The code there iterates over the marked regions and after a number of subsequent calls draws stuff using roughly the same logic in `SkDraw` (only `drawRect()` instead of `drawPath()`) but in the end it's the same `SkScan` and `SkBlitter` that do the work.

All that code is pretty hard to wrap my head around instantly, but what did catch my eye is that `GradientDrawable` makes two calls to the whole native stack if it has both background and stroke (look here), while in any scenario a `NinePatch` only makes one.

So, without actually measuring times for both approaches I get a feeling in most cases `NinePatch` wins the race: if we [awfully] roughly assume that native call stacks for `drawRect()` and `drawPath()` use pretty much the same logic and [another awful simplification] the parameter sets that get passed around there and are created by `NinePatch` and `GradientDrawable` don't affect complexity of the methods that much, then `NinePatch` turns out to be roughly 2 times faster than `GradientDrawable` with filling and outline. Well, provided you use a regular, 9-section 9-Patch (i.e. don't shred you 9-Patch by an awful lot of markers, making the iteration over the pieces overly effort-expensive).

Anyone who'll stumble upon this and knows more on the subject (and/or better at estimating complexity of native code), please, correct me if I'm wrong.

PS yeah, I know this is not much of a straight answer

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