Ich arbeite an einer Zeichen-App, in der der Benutzer mit dem Finger oder dem Stift zeichnen / schreiben kann. Dafür habe ich Code aus verwiesenhttps://github.com/yusenhan/Smooth-Line-Viewin meiner Bewerbung.

Das Problem, dem ich gegenüberstehe, ist, dass das Schreiben manchmal, wenn Sie sehr nah schreiben, nicht sehr glatt ist.

Ich glaube, ich mache einen Fehler beim Erreichen des Kontrollpunkts.

Unten ist mein Code

// Finde den Mittelpunkt

CGPoint midPoint(CGPoint p1, CGPoint p2)
{
    return CGPointMake((p1.x + p2.x) * 0.5, (p1.y + p2.y) * 0.5);
}

#pragma mark Gesture handle
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{

    UITouch *touch = [touches anyObject];
    //LocationInView returns the current location of the reciever in coordinate system of the given View.
    m_previousPoint1 = [touch locationInView:self];
    m_previousPoint2 = [touch locationInView:self];
    m_currentPoint   = [touch locationInView:self];    

    [self touchesMoved:touches withEvent:event];}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{          
    //AnyObject:- Returns one of the objects in the set, or nil if the set contains no objects.
    UITouch *touch  = [touches anyObject];

    m_previousPoint2  = m_previousPoint1;
    m_previousPoint1  = m_currentPoint;
    m_currentPoint    = [touch locationInView:self];

    if(m_drawStep != ERASE)
    {
        m_drawStep = DRAW;
        m_drawing  = TRUE;        
    }    
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, 0.0);//creates a graphics context suitable for use as an image(size of the image,opquae,scale, if scale = 0.0, means platform will take care of scaling)
    [self.layer renderInContext:UIGraphicsGetCurrentContext()];
    m_curImage = UIGraphicsGetImageFromCurrentImageContext();// to turn the context into a UIImage    
    UIGraphicsEndImageContext();

 }

- (void)drawRect:(CGRect)rect
{
   CGPoint mid1 = midPoint(m_previousPoint1, m_previousPoint2);
   CGPoint mid2 = midPoint(m_currentPoint, m_previousPoint1);            

   [m_curImage drawAtPoint:CGPointMake(0, 0)];

   CGContextRef context = UIGraphicsGetCurrentContext();//Get a reference to current context(The context to draw)
   [self.layer renderInContext:context];
   //Simply keep referring to this context in below functions with proper arguments.
   CGContextMoveToPoint(context, mid1.x, mid1.y);//Position the current point
   CGContextAddQuadCurveToPoint(context, m_previousPoint1.x, m_previousPoint1.y, mid2.x, mid2.y);     
   CGContextSetLineCap(context, kCGLineCapRound);
   CGContextSetBlendMode(context, kCGBlendModeNormal);
   CGContextSetLineJoin(context, kCGLineJoinRound);
   CGContextSetLineWidth(context, self.lineWidth);
   CGContextSetStrokeColorWithColor(context, self.lineColor.CGColor);
   CGContextSetShouldAntialias(context, YES);
   CGContextSetAllowsAntialiasing(context, YES);
   CGContextSetAlpha(context, self.lineAlpha);           
   CGContextSetFlatness(context, 0.6);
   CGContextStrokePath(context);//paints(fills) the line along the current path.            
}

Meiner Meinung nach die Punkte, die ich in derCGContextAddQuadCurveToPoint kann optimiert werden, aber wie man das optimiert, verstehe ich nicht. Ich habe Dokumente gelesen, um Kontrollpunkte zu findenBezier Curve, aber ich verstehe nicht.

Also Freunde, bitte helft mir zu verstehen, wo ich falsch liege.