getWindowImageRect function
Implementation
Rect getWindowImageRect(String winName) {
final cWinName = winName.toNativeUtf8().cast<ffi.Char>();
final p = calloc<cvg.CvRect>();
cvRun(() => chighgui.cv_getWindowImageRect(cWinName, p));
calloc.free(cWinName);
return Rect.fromPointer(p);
}