使用CGPoint和/或CGSize定义CGRectmake

Question

这是一个非常简单的问题,我似乎无法找到答案.这该怎么做 :

CGRectMake(1, 3, size) 

要么

CGRectMake(pointB, size) 

要么

 CGRectMake(pointB, size.width, size.height) 

代替

CGRectMake(self.someview.frame.origin.x, self.someview.frame.origin.y, self.someotherview.frame.size.width, self.someotherview.frame.size.height) 

?? 谢谢 !:)

编辑:

该方法CGRectmake需要CGFloat.我希望它采取CGSize和/或CGpoint作为方法的参数.

Answer 1

我想这就是你的想法:

    - (void) logRects
    {
        CGFloat
            x      = 10.0,
            y      = 20.0,
            width  = 50.0,
            height = 60.0;

        CGPoint point = {x, y};
        CGSize  size  = {width, height};

        CGRect  rect1 = {1, 3, size};
        CGRect  rect2 = {point, size};
        CGRect  rect3 = {point, size.width, size.height};

            //using designated (named) initialisers
        CGRect  rect4 = {.origin.x=3, .origin.y=5, .size = {100,100}};

            //with designated initialisers, order doesn't matter
        CGRect  rect5 = {.size=size, .origin.x=3, .origin.y=5};

        NSLog (@"rect1 %@",NSStringFromCGRect(rect1));
        NSLog (@"rect2 %@",NSStringFromCGRect(rect2));
        NSLog (@"rect3 %@",NSStringFromCGRect(rect3));
        NSLog (@"rect4 %@",NSStringFromCGRect(rect4));
        NSLog (@"rect5 %@",NSStringFromCGRect(rect5));
    }

但请注意这里的讨论:
为什么要使用像CGRectMake这样的函数？

这种复合文字语法在我看来更容易阅读和写入,虽然函数在未来的防范方面具有优势(+你得到自动完成).

更新
另见最近的q&a:

我以前没见过的CGRect语法

Answer 2

CGRectMake(1,3,大小):

    CGRectMake(1, 3, size.width, size.heigh)

CGRectMake(pointB,size):

    CGRectMake(pointB.x, pointB.y, size.width, size.height)

CGRectMake(pointB,size.width,size.height):

    CGRectMake(pointB.x, pointB.y, size.width, size.height)

CGRect看起来像这样:

struct CGRect {
  CGPoint origin;
  CGSize size;
};
typedef struct CGRect CGRect;

CGPoint和CGSize看起来像这样:

struct CGPoint {
  CGFloat x;
  CGFloat y;
};
typedef struct CGPoint CGPoint;

struct CGSize {
  CGFloat width;
  CGFloat height;
};
typedef struct CGSize CGSize;

CGRectMake是以下功能:

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;
}

所以代替:

CGRect r = CGRectMake(pointB.x, pointB.y, size.width, size.height)

你可以简单地写:

CGRect r;

r.origin = pointB;
r.size = size;

如果您想创建自己的CGRectMake,请随意这样做:

CG_INLINE CGRect
MyPrivateCGRectMake(CGPoint p, CGSize s)
{
  CGRect rect;
  rect.origin = p;
  rect.size = s;
  return rect;
}

但是你无法改变现有函数接受的参数.