UIViewでtopとかrightとかで指定できるようにした拡張

UIView+frame.h

#import <UIKit/UIKit.h>

@interface UIView (frame)
@property (nonatomic, assign) CGPoint origin;
@property (nonatomic, assign) CGFloat left;
@property (nonatomic, assign) CGFloat right;
@property (nonatomic, assign) CGFloat top;
@property (nonatomic, assign) CGFloat bottom;

@property (nonatomic, assign) CGSize size;
@property (nonatomic, assign) CGFloat width;
@property (nonatomic, assign) CGFloat height;

@property (nonatomic, assign) CGPoint center;

@end

UIView+frame.m

#import "UIView+frame.h"

@implementation UIView (frame)

- (CGPoint)origin
{
    return self.origin;
}

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

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

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

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

- (void)setRight:(CGFloat)right
{
    CGRect frame = self.frame;
    frame.origin.x = right - frame.size.width;
    self.frame = frame;
}

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

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

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

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


- (CGSize)size
{
    return self.frame.size;
}

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

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

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

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

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

- (CGPoint)center
{
    return CGPointMake(self.left + self.width/2.0, self.top + self.height / 2.0 );
}

- (void)setCenter:(CGPoint)center
{
    CGRect frame = self.frame;
    frame.origin.x = center.x - frame.size.width / 2.0;
    frame.origin.y = center.y - frame.size.height / 2.0;
    self.frame = frame;
}

@end

import "UIView+frame.h"をすれば使えます。