title: draw line between two points in iphone?
body: <p><img src="https://i.stack.imgur.com/TIeaE.png" alt="enter image description here">
  The above picture indicate the redpoint, i like to join those points.</p>
  
  <p>I like to draw a line between two points, i've image in the imageview, i like to mark some part of the image to  indicate the spot,using touch event i placed the points</p>
  
  <pre><code>   -(void) drawRect:(CGRect)rect
  {
  
      if([pointarray count]==4)
      {
          float firstpointx= [[pointarray objectAtIndex:0]floatValue];
          float firstpointy= [[pointarray objectAtIndex:1]floatValue];
          float secondpointx= [[pointarray objectAtIndex:2]floatValue];
          float secondpointy= [[pointarray objectAtIndex:3]floatValue];
  
          CGContextRef ctx = UIGraphicsGetCurrentContext();
          CGContextSetStrokeColorWithColor(ctx, [UIColor blueColor].CGColor);
          CGContextSetLineWidth(ctx, 2.0);
          CGContextMoveToPoint(ctx, firstpointx, firstpointy);///move to ur first dot
          CGContextAddLineToPoint(ctx, secondpointx, secondpointy);//add line from first dot to second dot
          CGContextSetLineCap(ctx, kCGLineCapRound);
          CGContextStrokePath(ctx);
          [pointarray removeAllObjects];//remove first two points from ur array so that next line is not drawn in continuous with previous line
      }
  }
  -(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
  { 
      pointarray=[[NSMutableArray alloc]init];
      CGPoint curPoint = [[touches anyObject] locationInView:self.view];
      [pointarray addObject:[NSNumber numberWithFloat:curPoint.x]];
      [pointarray addObject:[NSNumber numberWithFloat:curPoint.y]];
      NSLog(@"the point array is %@",pointarray);
      [self.view setNeedsDisplay]; // calls drawRectMethod
  }
  - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
  }
  
  
  - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
  
      UITouch *touch = [touches anyObject];
  
      if ([touch tapCount] == 2) {
          imageView.image = nil;
          return;
      }
  
      if(!mouseSwiped) {
          UIGraphicsBeginImageContext(self.view.frame.size);
          [imageView.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
          CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
          CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0);
          CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 1.0, 0.0, 0.0, 1.0);
          CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
          CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
          CGContextStrokePath(UIGraphicsGetCurrentContext());
          CGContextFlush(UIGraphicsGetCurrentContext());
          imageView.image = UIGraphicsGetImageFromCurrentImageContext();
          UIGraphicsEndImageContext();
  
      }
  
  }
  </code></pre>
  
  <p>Afer i placed the points i stuk here how to connect the two points, can someone help me!!!</p>