Algorithms used in android.graphics.Canvas

问题

I am trying to find out what drawing algorithms android.graphics.Canvas is using, and especialy for drawLine and drawCircle. I have managed to find Canvas_Delegate.java, but I cannot understand which algorithm is used in each occasion.

Any idea?

回答1:

Summarizing the comments:

• There are at least two implementations of the drawing functions, one purely in software (the Skia library), and one that uses the GPU when hardware acceleration is enabled.

• The Skia implementation is written in C++, not Java. Because it has to take into account Paint features like stroke width, the code may not appear as straightforward as the classic implementation you found.

• The implementation of a given algorithm is often much faster when written in C++ than it is when written in the Java programming language. This is something of a religious issue, with various benchmarks periodically thrown around to dispel the "Java is slow" notion. I think C++ is a bit more expressive, allowing you to tell the compiler more exactly what you want it to do, and on Android in particular the NDK C++ compiler is significantly better than the Dalvik or Art compilers.

来源：https://stackoverflow.com/questions/27871855/algorithms-used-in-android-graphics-canvas