(Move QT_FORWARD_DECLARE_CG to qglobal.h)
This function converts to CGImage for supported formats. This
is done by creating a CGImageRef that reuses the QImage data.
The CGImage and QImage ref counting systems are bridged, implemented
by using CGDataProvider that holds a copy of the QImage.
Unlike the previous internal implementation this public version
does not implicitly convert unsupported formats to ARGB32_Premultiplied.
See included documentation for the complete description.
Change-Id: Ie3984a7a8331e02a6f1c42943caaf76854e93538
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@qt.io>