Рисование по точкам в Quartz 2D

 
//
//  PaintViewController.m
//  Paint_1
//
//  Created by Admin on 21/10/2013.
//  Copyright (c) 2013 Viacheslav. All rights reserved.
//
 
#import "PaintViewController.h"
 
@interface PaintViewController ()
 
@end
 
@implementation PaintViewController
 
- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    //Инициализация переменных
    red = 0.0/255.0;
    blue = 0.0/255.0;
    green = 0.0/255.0;
    
    brush = 10.0;
       
}
 
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    mouseSwiped = NO;
    UITouch *touch = [touches anyObject];
    lastPoint = [touch locationInView:self.view];
}
 
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{   UITouch *touch = [touches anyObject];
    CGPoint currentPoint = [touch locationInView:self.view];
    lastPoint = currentPoint;
    
   
        UIGraphicsBeginImageContext(self.view.frame.size);
        [self.Canvas.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
        
        CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
        CGContextSetLineWidth(UIGraphicsGetCurrentContext(), brush);
        CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), red, green, blue, 1.0);
        CGContextMoveToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
        CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
        CGContextStrokePath(UIGraphicsGetCurrentContext());
        CGContextFlush(UIGraphicsGetCurrentContext());
        self.Canvas.image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
}

 
//
//  PaintViewController.h
//  Paint_1
//
//  Created by Admin on 21/10/2013.
//  Copyright (c) 2013 Viacheslav. All rights reserved.
//
 
#import <UIKit/UIKit.h>
 
@interface PaintViewController : UIViewController
{
    CGPoint lastPoint;
    CGFloat red;
    CGFloat blue;
    CGFloat green;
    CGFloat brush;
    
    BOOL mouseSwiped;
}
@property (weak, nonatomic) IBOutlet UIImageView *Canvas;
 
 
@end

#import <QuartzCore/QuartzCore.h>
...
@property (nonatomic, strong) NSMutableArray *allTouches;
...
 
- (void)viewDidLoad
{
  [super viewDidLoad];
  self.allTouches = [NSMutableArray array];
  self.view.multipleTouchEnabled = YES;
}
 
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
  [self.allTouches addObjectsFromArray:[touches allObjects]];
}
 
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
  UIGraphicsBeginImageContextWithOptions(self.view.layer.bounds.size, NO, 0.0);
  CGContextRef context = UIGraphicsGetCurrentContext();
  CGContextSetLineWidth(context, 2.f);
  CGContextSetStrokeColorWithColor(context, [UIColor blueColor].CGColor);
  CGContextSetFillColorWithColor(context, [UIColor redColor].CGColor);
  
  CGFloat rectSide = 10.f;
  CGRect pointRect = CGRectMake(0, 0, rectSide, rectSide);
  
  UITouch *firstTouch = [self.allTouches objectAtIndex:0];
  CGPoint firstPoint = [firstTouch locationInView:self.view];
  CGContextMoveToPoint(context, firstPoint.x, firstPoint.y);
  CGMutablePathRef path = CGPathCreateMutable();
  
  CGPathMoveToPoint(path, NULL, firstPoint.x, firstPoint.y);
  for (UITouch *touch in self.allTouches) {
    CGPoint point = [touch locationInView:self.view];
    pointRect.origin.x = point.x - rectSide/2;
    pointRect.origin.y = point.y - rectSide/2;
    CGContextAddEllipseInRect(context, pointRect);
    CGPathAddLineToPoint(path, NULL, point.x, point.y);
  }
  
  CGContextFillPath(context);
  CGContextAddPath(context, path);
  CGContextStrokePath(context);
  self.view.layer.contents = (id)UIGraphicsGetImageFromCurrentImageContext().CGImage;
  
  CGPathRelease(path);
  UIGraphicsEndImageContext();
}
 
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)eventevent {
  [self.allTouches removeObjectsInArray:[touches allObjects]];
}

        CGContextMoveToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
        CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
        CGContextStrokePath(UIGraphicsGetCurrentContext());