UIViewExt.m

/*
 Erica Sadun, http://ericasadun.com
 iPhone Developer's Cookbook, 3.0 Edition
 BSD License, Use at your own risk
 */

#import "UIViewExt.h"

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

double radians(float degrees) {
    return ( degrees * 3.14159265 ) / 180.0;
}

CATransform3D getTransForm3DWithAngle(CGFloat angle)
{
    CATransform3D  transform = CATransform3DIdentity;
    transform  = CATransform3DRotate(transform, angle, 0, 0, 1);
    return transform;
}

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;	
}

- (UIImage *)convertViewToImage
{
    CGSize s = self.bounds.size;
    //下面方法，第一个参数表示区域大小。
    //第二个参数表示是否是非透明的。如果需要显示半透明效果，需要传NO，否则传YES。
    //第三个参数就是屏幕密度。
    
    UIGraphicsBeginImageContextWithOptions(s, NO, [UIScreen mainScreen].scale);
    [self.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}
@end