[Lazarus] OS X Retina, TBitmap

[Alex]

I see problem on Retina (OSX) which is not fixed by last patch of Yury 
Sidorov (he posted patch for Retina at mantis)
Problem is with TBitmap
My ATSynEdit creates temp TBitmap of usual resolution (eg 1024*800) and 
in OnPaint it copies bitmap to canvas. It uses TCanvas.CopyRect.
This gives blurred image on mac with Retina: fonts blurred.
What we need is HiDPI bitmap? How to do it? How to fix Carbon widgetset?

Alex