Objective C: How do i smoothen the brush like a real brush? - objective-c

Question

I am building a brush app, it's almost finish and what i did was just a basic brush/drawing tool. I want to give it a more brush-like feel because in my current output it has angles and it doesn't look like a real brush ink.
here's my code:
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
touchSwiped = YES;
UITouch *touch = [touches anyObject];
currentTouch = [touch locationInView:self.view];
currentTouch.y -= 20;
UIGraphicsBeginImageContext(self.view.frame.size);
[touchDraw.image drawInRect:CGRectMake(0, 0, touchDraw.frame.size.width, touchDraw.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 35.0);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), redAmt, blueAmt, greenAmt, 1.0);
CGContextBeginPath(UIGraphicsGetCurrentContext());
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), endingPoint.x, endingPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentTouch.x, currentTouch.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
touchDraw.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
endingPoint = currentTouch;
touchMoved++;
if (touchMoved == 10) {
touchMoved = 0;
}
}

Answer 1

I don't know that you'll be able to use touch events for this without getting the angles you describe. The resolution of the events just aren't discrete enough.
OpenGL seems a better fit. Check out Apple's GLPaint sample code for an example.

Answer 2

Try using the quadCurve instead of addLineToPoint.. Quad Curve make a line in a two points that don't have an angle and make your line a curve..
CGPoint midPoint(CGPoint p1,CGPoint p2)
{
return CGPointMake ((p1.x + p2.x) * 0.5,(p1.y + p2.y) * 0.5);
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event//upon moving
{
mouseSwiped = YES;
UITouch *touch = [touches anyObject];
previousPoint2 = previousPoint1;
previousPoint1 = currentTouch;
currentTouch = [touch locationInView:self.view];
CGPoint mid1 = midPoint(previousPoint2, previousPoint1);
CGPoint mid2 = midPoint(currentTouch, previousPoint1);
// here's your ticket to the finals..
CGContextMoveToPoint(context, mid1.x, mid1.y);
CGContextAddQuadCurveToPoint(context, previousPoint1.x, previousPoint1.y, mid2.x, mid2.y);
CGContextStrokePath(context)
}