Fastest / most efficient way to draw moving speech bubbles on screen - CoreAnimation, Quartz2D?

I am adding some functionality to an iPhone app, and could use some help in picking the fastest / most efficient / best practice approach for solving this problem:

At the upper-half of my screen, I have speech bubbles (think comic book) that are UIImageViews translating across the screen (dynamic x & y position). It is a UIImageView because there is an image as the 开发者_Python百科background of the speech bubble.

Each speech bubble has a matching image moving around the bottom of the screen (elsewhere in the layer tree)

I would like to draw a tail (that triangle bit from a speech bubble) so the point of the triangle is tracking the lower image, with the base of the triangle being attached to the bottom of the upper UIImageView. (technically the base doesn't have to be butted against, it can overlap as long as I can match the color of my background image to the triangle).

I have already done all the tracking & drawn a line with CGContextStrokePath methods, and now I am stuck on how to replace the line with a triangle.

I have looked at drawing a triangle in Quartz and filling it. My concern is the speech bubbles are repositioned every 1/10th of a second, and it looks like drawing just the line used for proof of concept had a pretty severe performance / visual smoothness impact.

One idea I have is to do the trigonometry myself, and stretch & rotate an image of a triangle to connect each of these speech bubbles with the lower spot. Something is telling me there is a more efficient / more elegant solution, but I am not able to see it looking through the documentation. Any help on how you have or would approach this issue is appreciated. Thanks.

If the speech bubbles are fixed in size, just use a static UIImage. Set the image view's layer.position property at the point of the triangle. Then you can use view animation to move the bubbles around.

If you need the speech bubbles to be different sizes, I'd create a resizeable image using resizableImageWithCapInsets. Then I'd do the same as above to position it.

If there was something special about the speech bubble that I could't achieve with either a static image or a resizable image, I'd probably create a custom CA Layer or layers to get the effect I wanted (Like a gradient layer with a shape layer as it's mask layer)