iOS 画圈

Question

我正在尝试在我的 iOS 应用程序中创建下面的圆圈。我知道如何制作圆圈，但不完全确定如何沿着弧线获得点。它必须是代码而不是图像。下面也是我目前拥有的代码。

 - (void)drawRect:(CGRect)rect
{
    CGPoint point;
    point.x = self.bounds.origin.x + self.bounds.size.width/2;
    point.y = self.bounds.origin.y + self.bounds.size.height/2;

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetLineWidth(context, 2.0);

    CGContextSetStrokeColorWithColor(context, [UIColor blueColor].CGColor);

    CGRect circle = CGRectMake(point.x/2,point.y-point.x/2,point.x,point.x);

    CGContextAddEllipseInRect(context, circle);

    CGContextStrokePath(context);

    for (int i = 0; i<8; i++) {
        CGRect circleMini = CGRectMake(??????,??????,point.x/4,point.x/4);

        CGContextAddEllipseInRect(context, circleMini);
        CGContextStrokePath(context);
    }

}

更新回答

 float cita = 0;
for (int i = 0; i<8; i++) {

    CGPoint pointCir = CGPointMake(point.x/2 + radius * cos(cita) , (point.y-point.x/2) + radius * sin(cita) );
    CGRect circleMini = CGRectMake(pointCir.x,pointCir.y,radius/4,radius/4);

    CGContextAddEllipseInRect(context, circleMini);
    CGContextStrokePath(context);
    cita += M_PI / 4.0;
}

Answer 1

如果 (x,y) 是圆心，r 是大圆的半径，则第 i 个外圆的圆心将是:

  center(i) = ( x + r * cos(cita) , y + r * sin(cita) )

从 0 开始 cita 并为下一个圆(或 45 度)递增 PI/4 弧度

工作实现

CGFloat cita = 0;
CGFloat bigCircleRadius = point.x / 2.0;
CGFloat smallCircleRadius = bigCircleRadius / 4.0;
for (int i = 0; i < 8; i++) {

    CGPoint smallCircleCenter = CGPointMake(point.x  + bigCircleRadius * cos(cita) - smallCircleRadius/2.0 , point.y + bigCircleRadius * sin(cita) - smallCircleRadius / 2.0 );
    CGRect smallCircleRect = CGRectMake(smallCircleCenter.x,smallCircleCenter.y,smallCircleRadius,smallCircleRadius);

    CGContextAddEllipseInRect(context, smallCircleRect);
    CGContextStrokePath(context);
    cita += M_PI / 4.0;
}

编辑:添加了实现并重命名了变量。