捏合視圖變化(視圖的縮放), 單擊隨着鼠標移動, 雙擊放大視圖,再雙擊還原視圖

//
//  CLView.m
//  Homework_UIEvent
//
//  Created by lanouhn on 14-8-26.
//  Copyright (c) 2014年 [email protected] 陳聰雷. All rights reserved.
//

#import "CLView.h"

@interface CLView ()
//{
//    CGPoint _firstPreviousLocation;
//    CGPoint _secondPreviousLocation;
//}
@end

@implementation CLView

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
        self.multipleTouchEnabled = YES;
    }
    return self;
}

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

    static int i = 1;
    //雙擊放大, 再次雙擊恢復
    if (1 == touches.count && 2 == [[touches anyObject] tapCount]) {
        if (1 == i % 2) {
            self.bounds = CGRectMake(0, 0, self.bounds.size.width * 3.0, self.bounds.size.height * 3.0);
        } else {
            self.bounds = CGRectMake(0, 0, self.bounds.size.width / 3.0, self.bounds.size.height / 3.0);
        }
        i++;
    }
}

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

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

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    //獲取兩個點移動之後的位置
    NSArray *allTouches = [touches allObjects];
    UITouch *firstTouch = [allTouches firstObject];
    UITouch *secondTouch = [allTouches lastObject];
    
    //獲取兩個手指之前的位置
    CGPoint firstPreviousLocation = [firstTouch previousLocationInView:self];
    CGPoint secondPreviousLocation = [secondTouch previousLocationInView:self];
    //獲取兩個手指當前位置
    CGPoint firstCurrentLocation = [firstTouch locationInView:self];
    CGPoint secondCurrentLocation = [secondTouch locationInView:self];
    
    //若只有一個手指觸摸屏幕並移動時, view同樣移動
    if (1 == [touches count]) {
        self.center = CGPointMake(self.center.x + firstCurrentLocation.x - firstPreviousLocation.x, self.center.y + firstCurrentLocation.y - firstPreviousLocation.y);
        return;
    }
    
    
    //獲取之前兩個點的距離
    CGFloat previousDistance = [self distanceOfPoint1:firstPreviousLocation point2:secondPreviousLocation];
    //獲取當前兩個點的距離
    CGFloat currentDistance = [self distanceOfPoint1:firstCurrentLocation point2:secondCurrentLocation];
    
//    NSLog(@"%g", previousDistance);
    //求變化的比例
    CGFloat scale = currentDistance / previousDistance;
    //修改視圖的大小, 按比例縮放
    self.bounds = CGRectMake(0, 0, self.bounds.size.width * scale, self.bounds.size.height * scale);
    
}

//計算兩個點的距離
- (CGFloat)distanceOfPoint1:(CGPoint)point1 point2:(CGPoint)point2
{
    CGFloat dx = point1.x - point2.x;
    CGFloat dy = point1.y - point2.y;
    return sqrt(pow(dx, 2) + pow(dy, 2));
}

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
    // Drawing code
}
*/

@end