实现图片的移动和缩放的功能类（move and zoom）

头文件

--------------------------------------------------------------------------------------------

EditImgView.h

#import <Foundation/Foundation.h>

#import <QuartzCore/QuartzCore.h>

@interface EditImgView : UIImageView {

CGFloat zoom;

CGPoint previousPoint; // used in move

BOOL moving;

CGFloat previousDistance; // used in pinch zoom

}

-(id)initWithImg:(UIImage*)img;

-(void)configureTiledLayer;

@end

--------------------------------------------------------------------------------------------

实现类

---------

EditImgView.m

#import "EditImgView.h"

#import "Logger.h"

#define EXPAND_FRE 5/4

#define REDUCE_FRE 4/5

#define MIDDLE_FRE 1

#define MULTIPLE 3

@implementation EditImgView

-(id)initWithImg:(UIImage*)img

{

if (self = [super init])

{

self.image = img;

self.userInteractionEnabled = YES;

self.multipleTouchEnabled = YES;

[self configureTiledLayer];

[self setNeedsLayout];

}

return self;

}

- (void)configureTiledLayer {

zoom = MIDDLE_FRE;

moving = NO;

}

- (void)setZoom:(CGFloat)newZoom {

zoom = newZoom;

self.transform = CGAffineTransformMakeScale(zoom,zoom);

}

- (void)zoomIn {

[self setZoom:zoom * EXPAND_FRE];

}

- (void)zoomOut {

[self setZoom:zoom * REDUCE_FRE];

}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

[super touchesBegan:touches withEvent:event];

touches = [event allTouches];

if(touches.count >= 2)

{

NSArray *touches = [event.allTouches allObjects];

CGPoint pointOne = [[touches objectAtIndex:0] previousLocationInView:self];

CGPoint pointTwo = [[touches objectAtIndex:1] previousLocationInView:self];

previousDistance = sqrt(pow(pointOne.x - pointTwo.x, 2.0f) +

pow(pointOne.y - pointTwo.y, 2.0f));

}

else if(touches.count == 1)

{

previousPoint = [[touches anyObject] locationInView:self];

}

}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

[super touchesMoved:touches withEvent:event];

if(touches.count == 1) {

CGPoint currentPoint = [[touches anyObject] locationInView:self];

previousPoint = [[touches anyObject] previousLocationInView:self];

if (![NSStringFromCGPoint(currentPoint) isEqualToString:NSStringFromCGPoint(previousPoint)])

{

CGPoint delta = CGPointMake(currentPoint.x - previousPoint.x, currentPoint.y - previousPoint.y);

self.center = CGPointMake(self.center.x + delta.x * zoom,

self.center.y + delta.y * zoom);

previousPoint = currentPoint;

NSLog(@"---------string == %@",NSStringFromCGRect(self.frame));

moving = YES;

}

}

else if (touches.count != 2)

{

return;

}

else if(touches.count == 2) {

NSArray *touches = [event.allTouches allObjects];

CGPoint pointOne = [[touches objectAtIndex:0] locationInView:self];

CGPoint pointTwo = [[touches objectAtIndex:1] locationInView:self];

CGFloat distance = sqrt(pow(pointOne.x - pointTwo.x, 2.0f) +

pow(pointOne.y - pointTwo.y, 2.0f));

CGFloat newZoom = 1;

if (previousDistance != 0)

{

newZoom = fabs(zoom+(distance - previousDistance) / (previousDistance));

}

[self setZoom:newZoom];

previousDistance = distance;

}

}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

if(!moving) {

if(touches.count == 1) {

if([[touches anyObject] tapCount] == 2) {

[NSObject cancelPreviousPerformRequestsWithTarget:self];

[self zoomOut];

} else {

[self performSelector:@selector(zoomIn) withObject:nil afterDelay:0.25];

}

}

} else {

moving = NO;

}

}

- (void)dealloc {

[super dealloc];

}

@end