实现图片的移动和缩放的功能类（move and zoom）

头文件

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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

 

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实现类

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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