How to compare two CGSize variables?

To check for equality you can use, CGSizeEqualToSize function by Apple.

CGSize firstSize = CGSizeMake(1.0,1.0);CGSize secondSize = CGSizeMake(5.0,3.0);if(CGSizeEqualToSize(firstSize, secondSize)) {    //they are equal}else{    //they aren't equal}

Determine whether firstSize fits into secondSize without rotating:

if(firstSize.width <= secondSize.width && firstSize.height <= secondSize.height)

The following function determines if the rectangle of the CGSize in the first parameter fits wholly within or at the extent of the rectangle of the CGSize in the second parameter.

- (BOOL)size:(CGSize)smallerSize isSmallerThanOrEqualToSize:(CGSize)largerSize {    return CGRectContainsRect(        CGRectMake(0.0f, 0.0f, largerSize.width, largerSize.height),        CGRectMake(0.0f, 0.0f, smallerSize.width, smallerSize.height)    );}

Instead of writing the full logic yourself with difficult to read conditional statements, you can use the built-in, inline helper functions whose names are descriptive.

While I haven't done the research, this method is probably slower in execution than the accepted answer since it involves converting the two CGSizes to two CGRects C structs. Though it does have the advantage of being quicker to comprehend by the reader.