Resizable MKOverlay using MKOverlayRenderer

Question

I want to have a custom MKOverlay that's a circle anchored to the user location annotation that the user can resize by pinching. I was able to successfully achieve this using MKOverlayPathRenderer and a custom MKOverlay object by overriding the createPath method and making an arc. The resizing and moving of the overlay was handled by using KVO on the radius and coordinate properties of my overlay. However the resizing was incredibly choppy and the boundingMapRect wasn't correctly calculated.

I've also tried using an image and instead of subclassing MKOverlayPathRenderer just MKOverlayRenderer, overriding - (void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context but when I resize my CPU percentage jumps to 160% usage (not great yeah?) and the boundingRect is again being drawn incorrectly.

I really think the way to do it is with MKOverlayPathRenderer and maybe having an atomic counter of some kind so that a redraw only gets called say every 5 or 10 times the pinch gesture is triggered.

Does anyone have any suggestions? I've also considered but haven't tried making a UIView and adding it as a subview to the map view and putting the pinch gesture on that but that seems hacky and dirty.

Please describe for the first case with KVO and MKOverlayPathRenderer how did you forced recalculation of your path. — Eugene Dudnyk, Feb 26 '14 at 00:30
Instead of the circle shrinking and expanding, I made it so that the circle is always the same visual width and the map zooms in and out. — barndog, Mar 14 '14 at 20:06

score 0 · Answer 1 · answered Feb 26 '14 at 00:32

0

When you computed new boundingMapRect on the Overlay, you must invoke invalidatePath on your Renderer. After that, system will invoke createPath for you when appropriate.

answered Feb 26 '14 at 00:32

Eugene Dudnyk

5,553
1
23
48

Resizable MKOverlay using MKOverlayRenderer

1 Answers1

Linked