Does anyone know why the performance of canvas on mobile safari in iOS 6 drops significantly in landscape mode?

Question

I created a webapp (app.neoscores.com) which generally performs really well on all devices/platforms (still beta).
Except on iOS 6 in landscape(!?). When you turn your iPad/iPhone in landscape, the pager below (to turn the pages ;-) ) is significant slower...

This certainly was not the case on iOS 5!!! What happened? iOS 6 Safari bug???

Does someone has the answer?

Thx.

Answer 1

First off, showing music scores on different devices using canvas - I love it.

Second - Are you using the same device, or did you get the iPhone 5? It has a larger resolution and that may slow down rendering times.

Third - If you're rendering from a larger image, this may help - https://github.com/stomita/ios-imagefile-megapixel . There is some subsampling change (bug?) going on in iOS6 that may be affecting you.