Quartz2D-06.利用贝瑟尔曲线画饼状图

• 效果图
  
• 代码实现

#import "ZJCakeView.h"
@implementation ZJCakeView
- (void)drawRect:(CGRect)rect {
    // 计算需要的位置
    CGFloat radius = self.bounds.size.width * 0.5;
    CGPoint center = CGPointMake(radius, self.bounds.size.height * 0.5);
    CGFloat statA = 0;
    CGFloat angle = 0;
    CGFloat endA = 0;


    NSArray *data = @[@20,@20,@35,@25];

    // 根据传入的数据计算各个扇形的起始点
    for (int i = 0; i < data.count; i++) {
        int num = [data[i] intValue];
        statA = endA;
        angle = num/100.0 * M_PI * 2;
        endA = statA + angle;

        // 创建贝瑟尔路径
        UIBezierPath *path = [UIBezierPath bezierPath];

        [path addArcWithCenter:center radius:radius startAngle:statA endAngle:endA clockwise:YES];
        [path addLineToPoint:center];
        [[self randomColor] set];
        [path fill];
    }
}

// 随机颜色
-(UIColor *)randomColor{
    CGFloat r = arc4random_uniform(256)/255.0;
    CGFloat g = arc4random_uniform(256)/255.0;
    CGFloat b = arc4random_uniform(256)/255.0;

    return [UIColor colorWithRed:r green:g blue:b alpha:1];

}
@end