When I draw lines and shapes etc I get the " current graphics context" in iOS.
What exactly though is " current graphics context" - I'm looking for the 30,000 foot description.
Right now I just copy and paste UI code, not exactly sure what it's doing.
The OS needs a place to save information, such as drawing state, which you don't want to specify in every single CG drawing command, such as in which bitmap or view to draw, the scale or other transform to use, the last color you specified, etc.
The context tells each CG call where to find all this "stuff" for your current drawing call. Give a different context to the exact same drawing call, and that call might draw to a different bitmap in a completely different view, with a different color, different scale, etc.