Forces all pending drawing operations in a window context to be rendered immediately to the destination device.
- iOS 2.0+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
- Core Graphics
The window context to flush. If you pass a PDF context or a bitmap context, this function does nothing.
When you call this function, Core Graphics immediately flushes the current drawing to the destination device (for example, a screen). Because the system software flushes a context automatically at the appropriate times, calling this function could have an adverse effect on performance. Under normal conditions, you do not need to call this function.