We are developing screen capture utility which allows users to capture selected area on screen. Which works on 10.7 and above. As per apple Technical Q&A QA1741 we have used below API to capture screen.
CGDisplayCreateImageForRect(displayId,selectedArea)
This API works fine for normal scenario. Howerver there is one issue with systen screen zoom feature(cmd+shift+=)
Whenever we try to capture zoomed area, we are not getting correct output.
I know that we need to apply screen zoom factor to selected rect. But I am not finding any API to get screen zoom level. Can any one show me some pointers to resolve this issue.