There are two ways to handle drawing and animation:CPU (central processing unit) and GPU (graphics processor). In modern iOS devices, there are programmable chips that can run different software, but for historical reasons, we can say that the CPU does all the work at the software level, while the GPU is at the hardware level. in general, we can do anything with software (using the CPU), but for image processing, it is usually faster to use hardware because the GPU optimizes for highly parallel floating-point arithmetic using images. For some reason, we want to give the screen rendering work to the hardware as much as possible. The problem is that the GPU does not have unlimited performance, and once the resources are exhausted, performance starts to fall (even if the CPU is not fully occupied)
From here we can see that using the GPU will improve the performance of our app, but that the optimal solution is definitely smart allocation of GPU and CPU in iOS graphics core graphics with CPU and OpenGL ES with GPU in view of my Caishuxueqian We're only using the core graphics to make 2D drawings, but we should know that.
GPU CPU Differences in drawing