Cgfloat, cgpoint, cgsize, and cgrect in IOS

Cggeometry class defines the structure of geometric elements and functions for operating geometric elements.

1. Data Type:

Cgfloat: basic type of floating point value
Cgpoint: points in a two-dimensional coordinate system
Cgsize: indicates the width and height of a rectangle.
Cgrect: the position and size of a rectangle.

typedef float CGFloat;// 32-bittypedef double CGFloat;// 64-bitstruct CGPoint {    CGFloat x;    CGFloat y;};typedef struct CGPoint CGPoint;struct CGSize {    CGFloat width;    CGFloat height;};typedef struct CGSize CGSize;struct CGRect {    CGPoint origin;    CGSize size;};typedef struct CGRect CGRect;

Note: the height and width of the cgrect data structure can be negative. For example, the origin of a rectangle is [0.0, 0.0] And the size is [10.0, 10.0]. This rectangle is exactly the same as the rectangle where the source is [10.0, 10.0] And the size is [-10.0,-10.0.

2. Use values to create geometric elements

Cgpointmake

Cgrectmake

Cgsizemake

CGPoint CGPointMake (   CGFloat x,   CGFloat y);CGSize CGSizeMake (   CGFloat width,   CGFloat height);CGRect CGRectMake (   CGFloat x,   CGFloat y,   CGFloat width,   CGFloat height);

    CGFloat ten=10.0f;    CGPoint point = CGPointMake(0.0f, 0.0f);    CGSize size = CGSizeMake(10.0f, 10.0f);    CGRect rect = CGRectMake(point.x, point.y, size.width, size.height);    NSLog(@"ten: %f", ten);    NSLog(@"point: %@", NSStringFromCGPoint(point));    NSLog(@"size: %@", NSStringFromCGSize(size));    NSLog(@"rect: %@", NSStringFromCGRect(rect));

Address: http://www.cnblogs.com/chivas/archive/2012/05/16/2504006.html