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# CGRectUnion(_:_:)

Returns the smallest rectangle that contains the two source rectangles.

```
func CGRectUnion(_ r1: CGRect, _ r2: CGRect) -> CGRect
```

## Parameters

`r1`

The first source rectangle.

`r2`

The second source rectangle.

## Return Value

The smallest rectangle that completely contains both of the source rectangles.

## Discussion

Both rectangles are standardized prior to calculating the union. If either of the rectangles is a null rectangle, a copy of the other rectangle is returned (resulting in a null rectangle if both rectangles are null). Otherwise a rectangle that completely contains the source rectangles is returned.

---

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