When application developers draw images to the screen, there are two ways to do it. They can use Canvas or OpenGL. Beginning in Android 4.0, both methods use hardware acceleration by default. To use hardware acceleration, we need to use Open GL libraries and eventually the Gralloc module will be loaded as part of the graphics system initialization. As we saw in Chapter 3, Discovering Kernel, HAL, and Virtual Hardware, each HAL module has a reference ID that can be used by the hw_get_module function to load it to memory. The hw_get_module function is defined in the $AOSP/hardware/libhardware/hardware.c file:
int hw_get_module(const char *id, const struct hw_module_t **module) { return hw_get_module_by_class(id, ...
