OC-CoreGraphics - CGGeometry.h详解

/* CoreGraphics - CGGeometry.h

   Copyright (c) 1998-2011 Apple Inc.

   All rights reserved. */

#ifndef CGGEOMETRY_H_

#define CGGEOMETRY_H_

#include <CoreGraphics/CGBase.h>

#include <CoreFoundation/CFDictionary.h>

#include <CoreFoundation/CFBase.h>

#include <CoreFoundation/CFAvailability.h>

#include <stdint.h>

CF_IMPLICIT_BRIDGING_ENABLED

CF_ASSUME_NONNULL_BEGIN

/* Points. */

struct CGPoint {

    CGFloat x;

    CGFloat y;

};

typedef struct CGPoint CGPoint;

/* Sizes. */

struct CGSize {

    CGFloat width;

    CGFloat height;

};

typedef struct CGSize CGSize;

/* Vectors. */

#define CGVECTOR_DEFINED 1

struct CGVector {

    CGFloat dx;

    CGFloat dy;

};

typedef struct CGVector CGVector;

/* Rectangles. */

struct CGRect {

    CGPoint origin;

    CGSize size;

};

typedef struct CGRect CGRect;

/* Rectangle edges. */

typedef CF_ENUM(uint32_t, CGRectEdge) {

    CGRectMinXEdge, CGRectMinYEdge, CGRectMaxXEdge, CGRectMaxYEdge

};

/* The "zero" point -- equivalent to CGPointMake(0, 0). */

CG_EXTERN const CGPoint CGPointZero

      CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* The "zero" size -- equivalent to CGSizeMake(0, 0). */

CG_EXTERN const CGSize CGSizeZero

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* The "zero" rectangle -- equivalent to CGRectMake(0, 0, 0, 0). */

CG_EXTERN const CGRect CGRectZero

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* The "empty" rect. This is the rectangle returned when, for example, we

   intersect two disjoint rectangles. Note that the null rect is not the

   same as the zero rect. */

CG_EXTERN const CGRect CGRectNull

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* The infinite rectangle. */

CG_EXTERN const CGRect CGRectInfinite

    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Make a point from `(x, y)'. */

CG_INLINE CGPoint CGPointMake(CGFloat x, CGFloat y);

/* Make a size from `(width, height)'. */

CG_INLINE CGSize CGSizeMake(CGFloat width, CGFloat height);

/* Make a vector from `(dx, dy)'. */

CG_INLINE CGVector CGVectorMake(CGFloat dx, CGFloat dy);

/* Make a rect from `(x, y; width, height)'. */

CG_INLINE CGRect CGRectMake(CGFloat x, CGFloat y, CGFloat width,

  CGFloat height);

/* Return the leftmost x-value of `rect'. */

CG_EXTERN CGFloat CGRectGetMinX(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the midpoint x-value of `rect'. */

CG_EXTERN CGFloat CGRectGetMidX(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the rightmost x-value of `rect'. */

CG_EXTERN CGFloat CGRectGetMaxX(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the bottommost y-value of `rect'. */

CG_EXTERN CGFloat CGRectGetMinY(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the midpoint y-value of `rect'. */

CG_EXTERN CGFloat CGRectGetMidY(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the topmost y-value of `rect'. */

CG_EXTERN CGFloat CGRectGetMaxY(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the width of `rect'. */

CG_EXTERN CGFloat CGRectGetWidth(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the height of `rect'. */

CG_EXTERN CGFloat CGRectGetHeight(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return true if `point1' and `point2' are the same, false otherwise. */

CG_EXTERN bool CGPointEqualToPoint(CGPoint point1, CGPoint point2)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return true if `size1' and `size2' are the same, false otherwise. */

CG_EXTERN bool CGSizeEqualToSize(CGSize size1, CGSize size2)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return true if `rect1' and `rect2' are the same, false otherwise. */

CG_EXTERN bool CGRectEqualToRect(CGRect rect1, CGRect rect2)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Standardize `rect' -- i.e., convert it to an equivalent rect which has

   positive width and height. */

CG_EXTERN CGRect CGRectStandardize(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return true if `rect' is empty (that is, if it has zero width or height),

   false otherwise. A null rect is defined to be empty. */

CG_EXTERN bool CGRectIsEmpty(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return true if `rect' is the null rectangle, false otherwise. */

CG_EXTERN bool CGRectIsNull(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return true if `rect' is the infinite rectangle, false otherwise. */

CG_EXTERN bool CGRectIsInfinite(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

/* Inset `rect' by `(dx, dy)' -- i.e., offset its origin by `(dx, dy)', and

   decrease its size by `(2*dx, 2*dy)'. */

CG_EXTERN CGRect CGRectInset(CGRect rect, CGFloat dx, CGFloat dy)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Expand `rect' to the smallest rect containing it with integral origin and

   size. */

CG_EXTERN CGRect CGRectIntegral(CGRect rect)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the union of `r1' and `r2'. */

CG_EXTERN CGRect CGRectUnion(CGRect r1, CGRect r2)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return the intersection of `r1' and `r2'. This may return a null rect. */

CG_EXTERN CGRect CGRectIntersection(CGRect r1, CGRect r2)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Offset `rect' by `(dx, dy)'. */

CG_EXTERN CGRect CGRectOffset(CGRect rect, CGFloat dx, CGFloat dy)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Make two new rectangles, `slice' and `remainder', by dividing `rect' with

   a line that's parallel to one of its sides, specified by `edge' -- either

   `CGRectMinXEdge', `CGRectMinYEdge', `CGRectMaxXEdge', or

   `CGRectMaxYEdge'. The size of `slice' is determined by `amount', which

   measures the distance from the specified edge. */

CG_EXTERN void CGRectDivide(CGRect rect, CGRect *  slice,

    CGRect *  remainder, CGFloat amount, CGRectEdge edge)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return true if `point' is contained in `rect', false otherwise. */

CG_EXTERN bool CGRectContainsPoint(CGRect rect, CGPoint point)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return true if `rect2' is contained in `rect1', false otherwise. `rect2'

   is contained in `rect1' if the union of `rect1' and `rect2' is equal to

   `rect1'. */

CG_EXTERN bool CGRectContainsRect(CGRect rect1, CGRect rect2)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/* Return true if `rect1' intersects `rect2', false otherwise. `rect1'

   intersects `rect2' if the intersection of `rect1' and `rect2' is not the

   null rect. */

CG_EXTERN bool CGRectIntersectsRect(CGRect rect1, CGRect rect2)

    CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);

/*** Persistent representations. ***/

/* Return a dictionary representation of `point'. */

CG_EXTERN CFDictionaryRef  CGPointCreateDictionaryRepresentation(

    CGPoint point)

    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* Make a CGPoint from the contents of `dict' (presumably returned earlier

   from `CGPointCreateDictionaryRepresentation') and store the value in

   `point'. Returns true on success; false otherwise. */

CG_EXTERN bool CGPointMakeWithDictionaryRepresentation(

    CFDictionaryRef __nullable dict, CGPoint * __nullable point)

    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* Return a dictionary representation of `size'. */

CG_EXTERN CFDictionaryRef  CGSizeCreateDictionaryRepresentation(CGSize size)

    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* Make a CGSize from the contents of `dict' (presumably returned earlier

   from `CGSizeCreateDictionaryRepresentation') and store the value in

   `size'. Returns true on success; false otherwise. */

CG_EXTERN bool CGSizeMakeWithDictionaryRepresentation(

    CFDictionaryRef __nullable dict, CGSize * __nullable size)

    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* Return a dictionary representation of `rect'. */

CG_EXTERN CFDictionaryRef  CGRectCreateDictionaryRepresentation(CGRect)

    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/* Make a CGRect from the contents of `dict' (presumably returned earlier

   from `CGRectCreateDictionaryRepresentation') and store th
144d6
e value in

   `rect'. Returns true on success; false otherwise. */

CG_EXTERN bool CGRectMakeWithDictionaryRepresentation(

    CFDictionaryRef __nullable dict, CGRect * __nullable rect)

    CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

/*** Definitions of inline functions. ***/

CG_INLINE CGPoint

CGPointMake(CGFloat x, CGFloat y)

{

  CGPoint p; p.x = x; p.y = y; return p;

}

CG_INLINE CGSize

CGSizeMake(CGFloat width, CGFloat height)

{

  CGSize size; size.width = width; size.height = height; return size;

}

CG_INLINE CGVector

CGVectorMake(CGFloat dx, CGFloat dy)

{

  CGVector vector; vector.dx = dx; vector.dy = dy; return vector;

}

CG_INLINE CGRect

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

{

  CGRect rect;

  rect.origin.x = x; rect.origin.y = y;

  rect.size.width = width; rect.size.height = height;

  return rect;

}

CG_INLINE bool

__CGPointEqualToPoint(CGPoint point1, CGPoint point2)

{

  return point1.x == point2.x && point1.y == point2.y;

}

#define CGPointEqualToPoint __CGPointEqualToPoint

CG_INLINE bool

__CGSizeEqualToSize(CGSize size1, CGSize size2)

{

  return size1.width == size2.width && size1.height == size2.height;

}

#define CGSizeEqualToSize __CGSizeEqualToSize

CF_ASSUME_NONNULL_END

CF_IMPLICIT_BRIDGING_DISABLED

#endif /* CGGEOMETRY_H_ */

一、几个常用结构体

struct CGPoint {

  CGFloat x;

  CGFloat y;

};
定义一个点，设置x坐标和y坐标

struct CGSize {

  CGFloat width;

  CGFloat height;

};
定义一个尺寸，设置宽度和高度

struct CGVector {

  CGFloat dx;

  CGFloat dy;

};
定义一个二维矢量

struct CGRect {

  CGPoint origin;

  CGSize size;

};
定义一个矩形

二、几个系统定义的量

const CGPoint CGPointZero

零点，与CGPointMake(0, 0)等效

const CGSize CGSizeZero

零尺寸，与CGSizeMake(0, 0)等效

const CGRect CGRectZero

零矩形，与CGRectMake(0, 0,
0, 0)等效

const CGRect CGRectNull

空矩形，这个和零矩形并不相同，当我们返回两个不相交矩形的交集时，会返回空矩形。

const CGRect CGRectInfinite
无限的矩形

三、一些常用方法

CGPoint CGPointMake(CGFloat x,
CGFloat y);
创建一个点

CGSize CGSizeMake(CGFloat width,
CGFloat height);
创建一个尺寸

CGVectorMake(CGFloat dx,
CGFloat dy);
创建一个矢量

CGRect CGRectMake(CGFloat x,
CGFloat y, CGFloat width,

  CGFloat height);
创建一个矩形

CGFloat CGRectGetMinX(CGRect rect);

获得矩形最左边的x值

CGFloat CGRectGetMidX(CGRect rect);

获取矩形中点的x值

CGFloat CGRectGetMaxX(CGRect rect);

获取矩形最右端的x值

CGFloat CGRectGetMinY(CGRect rect);

获取矩形最上端的y值

CGFloat CGRectGetMidY(CGRect rect);

获取矩形中心点的y值

CGFloat CGRectGetMaxY(CGRect rect);

获取矩形最下端的y值

CGFloat CGRectGetWidth(CGRect rect);

获取矩形宽度

CGFloat CGRectGetHeight(CGRect rect);

获取矩形高度

bool CGPointEqualToPoint(CGPoint point1,
CGPoint point2);

判断两个点是否相等

bool CGSizeEqualToSize(CGSize size1,
CGSize size2);

判断两个尺寸是否相等

bool CGRectEqualToRect(CGRect rect1,
CGRect rect2);

判断两个矩形是否相等

CGRect CGRectStandardize(CGRect rect);

根据一个矩形创建一个标准的矩形

bool CGRectIsEmpty(CGRect rect);

判断是否为零矩形

CGRectIsNull(CGRect rect);

判断是否为空矩形

bool CGRectIsInfinite(CGRect rect);

判断是否为无限矩形

CGRect CGRectInset(CGRect rect,
CGFloat dx, CGFloat dy);

创建一个内嵌的矩形，中心和rect参数的中心一样，dx，dy对应内嵌的宽度和高度

比如：CGRect rect=
CGRectInset(CGRectMake(0,
0, 100,
100), 10, 10);

会创建出的rect为（10，10，80，80），dx，dy也可以为负值，则是创建出来的矩形会大于原矩形范围。

CGRect CGRectIntegral(CGRect rect)

根据一个矩形，返回四个参数都是整数的矩形

CGRect CGRectUnion(CGRect r1,
CGRect r2);

返回两个矩形的并集

CGRect CGRectIntersection(CGRect r1,
CGRect r2);

返回两个矩形的交集，如果没有交集，返回空矩形

CGRect CGRectOffset(CGRect rect,
CGFloat dx, CGFloat dy);

返回一个矩形，偏移量相对于rect

void CGRectDivide(CGRect rect,
CGRect *slice, CGRect *remainder,

  CGFloat amount,
CGRectEdge edge);

这个函数用来分割矩形，参数rect是源矩形，slice和remainder是分割后的两部分矩形，amount是分割线，edge是分割选项。

注意：1、edge是一个宏，定义了分割的方式如下：

      2、slice和remainder是地址。

            3、举例如下，将会分割出两个矩形分别为(40,0,60,100)(0,0,40,100);

bool CGRectContainsPoint(CGRect rect,
CGPoint point);

判断点是否在矩形内

bool CGRectContainsRect(CGRect rect1,
CGRect rect2);

判断矩形1是否包含矩形2

bool CGRectIntersectsRect(CGRect rect1,
CGRect rect2);

判断矩形1和矩形2是否相交

CFDictionaryRef CGPointCreateDictionaryRepresentation(CGPoint point);

返回一个表示点的字典

bool CGPointMakeWithDictionaryRepresentation(CFDictionaryRef dict,

  CGPoint *point);

将字典转换为点

CFDictionaryRef CGSizeCreateDictionaryRepresentation(CGSize size);

返回一个表示尺寸的字典

bool CGSizeMakeWithDictionaryRepresentation(CFDictionaryRef dict,

  CGSize *size) ;

将字典转换为尺寸

CFDictionaryRef CGRectCreateDictionaryRepresentation(CGRect);

返回一个表示矩形的字典

bool CGRectMakeWithDictionaryRepresentation(CFDictionaryRef dict,

  CGRect *rect);

将字典转化为矩形