CGGeometry中的方法

Creating a Geometric Primitive from Values //创建几何单元（点，尺寸，位置和尺寸）
CGPointMake
CGPoint CGPointMake (
   CGFloat x,
   CGFloat y
);

CGRectMake
CGRect CGRectMake (
   CGFloat x,
   CGFloat y,
   CGFloat width,
   CGFloat height
);

CGSizeMake
CGSize CGSizeMake (
   CGFloat width,
   CGFloat height
);


Modifying Rectangles //编辑矩形
CGRectDivide
Divides a source rectangle into two component rectangles.
//把一个源矩形分成两部分
void CGRectDivide (
   CGRect rect,
   CGRect *slice,
   CGRect *remainder,
   CGFloat amount,
   CGRectEdge edge
);

CGRectInset
Returns a rectangle that is smaller or larger than the source rectangle, with the same center point.
//返回的矩形和原来的矩形相同的中心，但是长和宽改变了
CGRect CGRectInset (
   CGRect rect,
   CGFloat dx,
   CGFloat dy
);


CGRectIntegral
Returns the smallest rectangle that results from converting the source rectangle values to integers.
//返回成整数的矩形
CGRect CGRectIntegral (
   CGRect rect
);

CGRectIntersection
Returns the intersection of two rectangles.
//返回两个矩形的重叠部分
CGRect CGRectIntersection (
   CGRect r1,
   CGRect r2
);

CGRectOffset
Returns a rectangle with an origin that is offset from that of the source rectangle.
//返回的矩形原点和原来的矩形是一样的，然后长和宽发生了变化
CGRect CGRectOffset (
   CGRect rect,
   CGFloat dx,
   CGFloat dy
);

CGRectStandardize
Returns a rectangle with a positive width and height.
//把矩形标准话，也就是说返回的矩形的长和宽是正值
CGRect CGRectStandardize (
   CGRect rect
);

CGRectUnion
Returns the smallest rectangle that contains the two source rectangles.
//返回的矩形是包含了两个矩形的最小矩形
CGRect CGRectUnion (
   CGRect r1,
   CGRect r2
);


Comparing Values 
//比较各种值
CGPointEqualToPoint//判断两个点是否相等
CGSizeEqualToSize
CGRectEqualToRect
CGRectIntersectsRect//判定两个矩形是否相交
bool CGRectIntersectsRect (
   CGRect rect1,
   CGRect rect2
);


Checking for Membership //判断拥有关系
CGRectContainsPoint
CGRectContainsRect


Getting Min, Mid, and Max Values //得到最大最小值
CGRectGetMinX
CGRectGetMinY
CGRectGetMidX
CGRectGetMidY
CGRectGetMaxX
CGRectGetMaxY

Getting Height and Width/ /得到高和宽
CGRectGetHeight
CGRectGetWidth

Checking Rectangle Characteristics //检查矩形的特性
CGRectIsEmpty//检查是否为空
Returns whether a rectangle has zero width or height, or is a null rectangle.

CGRectIsNull//检查是否为Null
Returns whether the rectangle is equal to the null rectangle.

CGRectIsInfinite//检查是否为无边
Returns whether a rectangle is infinite.