General sluggishness on iPhone

I noticed that whatever is drawn in JUCE on my iPhone, and no matter how big it is, there always seems to be a kind of lag while redrawing.

Example: When you move the “slide to unlock” slider when the iPhone is locked, you can see that it follows the finger very quickly & smoothly, you feel its responsiveness. When you move the slider in a JUCE app or whatever control that follows the finger’s movement, you can feel that the repainting is by far not as quick and constant as it is with the “slide to unlock” slider.

I don’t think it has anything to do with the rendering time itself, because I’ve checked in an example I did, and the rendering time was so high that it allowed about 80fps. Furthermore, even in big apps like Safari, the scrolling is still much faster than anything in JUCE.

Why is that, and how can I make it better? From the source codes I couldn’t immediately see the reason.


Unless there’s a secret trick that I don’t know about, the rendering all happens as efficiently as possible…

I know this post is old but this has been bothering me a bit too-- could using the ComponentAnimator to the value you slide to fix this problem? (also deleting the old animations every time a new value is entered) I’m probably going to test that soon, just figured I’d mention it in this old post, haha.