UIViewExt

#import <UIKit/UIKit.h>

CGPoint CGRectGetCenter(CGRect rect);
CGRect  CGRectMoveToCenter(CGRect rect, CGPoint center);

@interface UIView (ViewFrameGeometry)
@property CGPoint origin;
@property CGSize size;

@property (readonly) CGPoint bottomLeft;//左下角坐标
@property (readonly) CGPoint bottomRight;//右下角坐标
@property (readonly) CGPoint topRight;//右上角坐标

@property CGFloat height;//控件高
@property CGFloat width;//控件宽

@property CGFloat top;//控件顶部y值
@property CGFloat left;//控件左边距x值

@property CGFloat bottom;//控件底部y值
@property CGFloat right;//控件右边距x值

- (void) moveBy: (CGPoint) delta;
- (void) scaleBy: (CGFloat) scaleFactor;
- (void) fitInSize: (CGSize) aSize;

@end

#import "UIViewExt.h"

CGPoint CGRectGetCenter(CGRect rect)
{
    CGPoint pt;
    pt.x = CGRectGetMidX(rect);
    pt.y = CGRectGetMidY(rect);
    return pt;
}

CGRect CGRectMoveToCenter(CGRect rect, CGPoint center)
{
    CGRect newrect = CGRectZero;
    newrect.origin.x = center.x-CGRectGetMidX(rect);
    newrect.origin.y = center.y-CGRectGetMidY(rect);
    newrect.size = rect.size;
    return newrect;
}

@implementation UIView (ViewGeometry)

// Retrieve and set the origin
- (CGPoint) origin
{
    return self.frame.origin;
}

- (void) setOrigin: (CGPoint) aPoint
{
    CGRect newframe = self.frame;
    newframe.origin = aPoint;
    self.frame = newframe;
}


// Retrieve and set the size
- (CGSize) size
{
    return self.frame.size;
}

- (void) setSize: (CGSize) aSize
{
    CGRect newframe = self.frame;
    newframe.size = aSize;
    self.frame = newframe;
}

// Query other frame locations
- (CGPoint) bottomRight
{
    CGFloat x = self.frame.origin.x + self.frame.size.width;
    CGFloat y = self.frame.origin.y + self.frame.size.height;
    return CGPointMake(x, y);
}

- (CGPoint) bottomLeft
{
    CGFloat x = self.frame.origin.x;
    CGFloat y = self.frame.origin.y + self.frame.size.height;
    return CGPointMake(x, y);
}

- (CGPoint) topRight
{
    CGFloat x = self.frame.origin.x + self.frame.size.width;
    CGFloat y = self.frame.origin.y;
    return CGPointMake(x, y);
}


// Retrieve and set height, width, top, bottom, left, right
- (CGFloat) height
{
    return self.frame.size.height;
}

- (void) setHeight: (CGFloat) newheight
{
    CGRect newframe = self.frame;
    newframe.size.height = newheight;
    self.frame = newframe;
}

- (CGFloat) width
{
    return self.frame.size.width;
}

- (void) setWidth: (CGFloat) newwidth
{
    CGRect newframe = self.frame;
    newframe.size.width = newwidth;
    self.frame = newframe;
}

- (CGFloat) top
{
    return self.frame.origin.y;
}

- (void) setTop: (CGFloat) newtop
{
    CGRect newframe = self.frame;
    newframe.origin.y = newtop;
    self.frame = newframe;
}

- (CGFloat) left
{
    return self.frame.origin.x;
}

- (void) setLeft: (CGFloat) newleft
{
    CGRect newframe = self.frame;
    newframe.origin.x = newleft;
    self.frame = newframe;
}

- (CGFloat) bottom
{
    return self.frame.origin.y + self.frame.size.height;
}

- (void) setBottom: (CGFloat) newbottom
{
    CGRect newframe = self.frame;
    newframe.origin.y = newbottom - self.frame.size.height;
    self.frame = newframe;
}

- (CGFloat) right
{
    return self.frame.origin.x + self.frame.size.width;
}

- (void) setRight: (CGFloat) newright
{
    CGFloat delta = newright - (self.frame.origin.x + self.frame.size.width);
    CGRect newframe = self.frame;
    newframe.origin.x += delta ;
    self.frame = newframe;
}

// Move via offset
- (void) moveBy: (CGPoint) delta
{
    CGPoint newcenter = self.center;
    newcenter.x += delta.x;
    newcenter.y += delta.y;
    self.center = newcenter;
}

// Scaling
- (void) scaleBy: (CGFloat) scaleFactor
{
    CGRect newframe = self.frame;
    newframe.size.width *= scaleFactor;
    newframe.size.height *= scaleFactor;
    self.frame = newframe;
}

// Ensure that both dimensions fit within the given size by scaling down
- (void) fitInSize: (CGSize) aSize
{
    CGFloat scale;
    CGRect newframe = self.frame;
    
    if (newframe.size.height && (newframe.size.height > aSize.height))
    {
        scale = aSize.height / newframe.size.height;
        newframe.size.width *= scale;
        newframe.size.height *= scale;
    }
    
    if (newframe.size.width && (newframe.size.width >= aSize.width))
    {
        scale = aSize.width / newframe.size.width;
        newframe.size.width *= scale;
        newframe.size.height *= scale;
    }
    
    self.frame = newframe;
}
@end