having both scrolling and drawing - ios

Question

I created a drawing application. Since I use drawing on a large image I also need to have scrolling as well, but when I implemented scrolling, the drawing did not work any more.
I think there is a conflict on the touch event between drawing and scrolling.
I am thinking to do scrolling with two finger and drawing with one finger, but I could not find out how to implement it. I appreciate if any one could help me to fix this problem.
-(void)viewDidLayoutSubviews
{
scroller.scrollEnabled=YES;
scroller.contentSize=temp.frame.size;
toggledrawandscroll=false;
}
- (IBAction)changescrollstatues:(id)sender {
if(toggledrawandscroll){
//if draw is enable,disable it
toggledrawandscroll =false;
scroller.scrollEnabled=YES;
scroller.canCancelContentTouches=YES;
scroller.contentSize=temp.frame.size;
}
else{
toggledrawandscroll =true;
scroller.scrollEnabled=NO;
scroller.canCancelContentTouches=NO;
}
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
mouseSwiped = NO;
UITouch *touch = [touches anyObject];
lastPoint = [touch locationInView:self.view];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
//initial setting for touch point
mouseSwiped = YES;
UITouch *touch = [touches anyObject];
CGPoint currentPoint = [touch locationInView:self.view];
//set the concext
UIGraphicsBeginImageContext(self.view.frame.size);
[temp.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
//drawing setting
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 1);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(),red, green, blue, 1);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 1);
CGContextSetBlendMode(UIGraphicsGetCurrentContext(),kCGBlendModeNormal);
CGContextStrokePath(UIGraphicsGetCurrentContext());
temp.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
lastPoint = currentPoint;
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
if(!mouseSwiped) {
//initial seting
UIGraphicsBeginImageContext(self.view.frame.size);
[temp.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, opacity);
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
CGContextFlush(UIGraphicsGetCurrentContext());
temp.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
}

Answer 1

So it looks like you have a toggle to enable scrolling? If that is the case your changesscrollstatues method never enables the scroll and never sets your boolean to YES. Your scroller is always enabled so the touch event won't get captured.