繪製曲線矩形一個圓圈裏面iOS上

Question

我想畫一個多樣性輪（裏面曲線的矩形圓）看到：

circle http://api.ning.com/files/oKZwndeqeam7%2aMiO7f4BDUT%2aAgw3WsK3kW-b-wXjR8gCrCqVAv3RpyBAdi%2adYSLaca0kAYCY0Wk13bSHDnEbOVR1NNUuYotV/diversity_wheel3.JPG?width=500

我知道如何畫一個圓，但我不知道如何繪製基於圓形座標的曲線矩形。

我該怎麼做？

Answer 1

既然你知道如何畫圈圈，只是一些行添加到它的中心，你喜歡的東西您發佈的圖像：

- (void)drawRect:(CGRect)rect 
{ 
    CGPoint centerPoint = self.center; 
    CGFloat circleWidth = 30; 
    int numCircles = 4; 

    [[UIColor colorWithHue:0.53 saturation:1 brightness:0.6 alpha:1] setStroke]; 

    CGContextRef ctx = UIGraphicsGetCurrentContext(); 
    for(int i=numCircles-1;i>=0;i--){ 
     //calculate some color 
     CGFloat colorModifier = ((numCircles-i)/(float)numCircles); 
     [[UIColor colorWithHue:0.53 saturation:colorModifier*0.8+0.2 brightness:1-colorModifier*0.4 alpha:1] setFill]; 

     CGFloat radius = circleWidth*(i+1); 

     //draw the circle 
     CGContextFillEllipseInRect(ctx, CGRectMake(centerPoint.x-radius, centerPoint.y-radius, 2*radius, 2*radius)); 
     CGContextStrokeEllipseInRect(ctx, CGRectMake(centerPoint.x-radius, centerPoint.y-radius, 2*radius, 2*radius)); 

     if(i>0){ 
      //just add a random number of dividers here 
      int numDivider = 3+(arc4random()%5); 
      float angleStep = 2*M_PI/numDivider; 
      for(int j=0;j<numDivider;j++){ 
       CGFloat x = centerPoint.x + sinf(j*angleStep)*radius; 
       CGFloat y = centerPoint.y + cosf(j*angleStep)*radius; 
       CGContextMoveToPoint(ctx, centerPoint.x, centerPoint.y); 
       CGContextAddLineToPoint(ctx, x, y); 
       CGContextStrokePath(ctx); 
      } 
     } 
    } 
} 

只是畫一個弧形長方形一種可能性將是繪製並消除內圈。像這樣：

UIBezierPath *path = [UIBezierPath bezierPath]; 
    [path moveToPoint:self.center]; 
    [path addArcWithCenter:self.center radius:150 startAngle:-0.3 endAngle:0.3 clockwise:YES]; 
    [path fill]; 

    UIBezierPath *innerPath = [UIBezierPath bezierPath]; 
    [innerPath moveToPoint:self.center]; 
    [innerPath addArcWithCenter:self.center radius:120 startAngle:0 endAngle:2*M_PI clockwise:YES]; 
    CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeClear); 
    [innerPath fill];