Draws a frame around the inside of the specified rectangle.
- iOS 2.0+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
The rectangle defining the area in which to draw.
This function draws a frame around the inside of
rect in the stroke color of the current graphics context and using the
k blend mode. The width is equal to 1.0 in the current coordinate system. Because the frame is drawn inside the rectangle, it is visible even if drawing is clipped to the rectangle. If the current graphics context is
nil, this function does nothing.
This function may be called from any thread of your app.