MacOS: When initializing an openGL view with an existing window, call finishInit

[jkeller51]

I had some long-standing bugs in my software dealing with SFML not receiving certain window notifications. I had worked around them outside of SFML but during a recent dig through the code I found the cause. When creating an sf::RenderWindow with a frame size (e.g. telling SFML to make its own window), it makes its SFOpenGLView receive certain window notifications, including NSWindowDidChangeScreenNotification and NSWindowDidChangeScreenProfileNotification.

But when instantiating an sf::RenderWindow inside of an existing window, the SFOpenGLView is never set up to receive these notifications, so certain events are "missed" by SFML. For DPI-aware applications, this can cause unexpected behavior.

I'm not sure if there was a reason for leaving this out, but adding it back in makes more sense to me and more cleanly solves the problems I was having.

Your environment

• MacOS 11
• SFML 252d26a
• Xcode 12.4

Steps to reproduce

Create an NSWindow manually, then create an sf::RenderWindow by passing the NSWindow handle.

Expected behavior

When DPI scaling changes occur (e.g. passing between windows or changing display scaling), the sf::RenderWindow should receive an event. Currently this is supposed to be passed to the Event::Resized event.

Actual behavior

When the sf::RenderWindow is instantiated inside of an existing NSWindow, this notification is not received.

[eXpl0it3r]

Fixed with #1760