Objective-C, Core-Plot Real Time Graph vs CPU
I've been working on implementing a real time Core Plot graph into my application on OS X. To my dismay I noticed a fairly significant issue. Once the line gets to the end of the X-Axis and it starts scrolling to keep up with the line the CPU load hits 30-35% non-stop.
I figured before I proceed any further I had better go back and see if I had made some type of mistake in my code for the CPU to spike like that. There wasn't anything out of the ordinary that I noticed, and I tried to adjust the framerate and updating frequency but without luck. I decided to go back to the real time example project they include and it has the same effect on the CPU.
Is there anything I can do about this, or is that just the nature of real time graphing on
OS X?. .
Everything is fine for the first 50 frames (indicated by the line with arrows), but once it gets to the end of it that's where things turn for the worse.
Side Note: I noticed Swift does graphing in the Playground, and even though it's apparently not real time (and I'm using Obj-C) it looks really sharp. Is the Swift graphing feature only available within playgrounds, or is there a way to implement that into a project? I'm only mentioning this because I'm looking to find something soon that is efficient.
That's the expected behavior with Core Plot. Once the graph starts to scroll, it has to redraw the plot, both axes, and all of the grid lines for each animation frame. You could reduce the drawing load by decreasing the number of grid lines and/or axis tick marks.
The playground graphs are a private part of the playground environment.