I’ve been using MacOSLib to write code that creates PDF annotations via PDFKit (written by Charles, but I don’t think he ever integrated it with the main trunk). PDFKit is very buggy in Sierra (well documented) and code that worked in all earlier versions of macOS now either malfunctions or crashes my app. I’ve filed a radar, and the Apple engineer has asked me several questions, one about Xojo. I realize that the answer depends upon how MacOSLib works with PDFKit, and I can answer questions here about that. One thing I can say is that the crash requires installing an instance method (via MacOSLib) for the drawPage event – if I avoid that no crash, but also no callback when the page needs redrawing. The question is:
"I noticed the crash log also included references to the XojoFramework. With respect to the XojoFramework code inside your overloaded method, is this framework sensitive to the main thread? PDFKit renders its pages on multiple background threads and I wonder if your Xojo calls are trying to access the page when it hasnt fully finished rendering.
FWIW, the problem doesn’t just occur with MacOSLib. The MBS PDFKit code has the same issues.
Thanks for any insight