drawRect-抽奖之星 [英] drawRect - Draw Star

问题描述

我在视图上绘制注释。下面是我用来绘制星星的方法。

I am drawing annotations on a view. The approach i am using to draw star is below.

-(void)drawRect:(CGRect)rect {

CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 2.0);
CGFloat xCenter = rect.size.width / 2;
CGFloat yCenter = rect.size.height / 2;

float width;
if(rect.size.width > rect.size.height) {
    width = rect.size.height;
} else {
    width = rect.size.width;
}

double r = width / 2.0;
float flip = -1.0;

double theta = 2.0 * M_PI * (2.0 / 5.0); // 144 degrees

CGContextMoveToPoint(context, xCenter, r*flip+yCenter);

for (NSUInteger k=1; k<5; k++)
{
    float x = r * sin(k * theta);
    float y = r * cos(k * theta);
    CGContextAddLineToPoint(context, x+xCenter, y*flip+yCenter);
}

CGContextSetStrokeColorWithColor(context, self.color.CGColor);

CGContextClosePath(context);
CGContextStrokePath(context);

}

我想仅将星形的边界移除其他内线有什么办法可以实现？ （除了使用moveToPoint和addLine方法）

I want to have just borders of star removing other inner lines is there any way to achieve that? (apart from using moveToPoint and addLine methods)

推荐答案

使用以下代码：

-(void)drawRect:(CGRect)rect
{
    int aSize = 100.0;
    float color[4] = { 0.0, 0.0, 1.0, 1.0 }; // Blue
    CGColorRef aColor = CGColorCreate(CGColorSpaceCreateDeviceRGB(), color);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetLineWidth(context, aSize);
    CGFloat xCenter = 100.0;
    CGFloat yCenter = 100.0;

    float  w = 100.0;
    double r = w / 2.0;
    float flip = -1.0;

    CGContextSetFillColorWithColor(context, aColor);


    CGContextSetStrokeColorWithColor(context, aColor);

    double theta = 2.0 * M_PI * (2.0 / 5.0); // 144 degrees

    CGContextMoveToPoint(context, xCenter, r*flip+yCenter);

    for (NSUInteger k=1; k<5; k++) 
    {
        float x = r * sin(k * theta);
        float y = r * cos(k * theta);
        CGContextAddLineToPoint(context, x+xCenter, y*flip+yCenter);
    }

    CGContextClosePath(context);
    CGContextFillPath(context);
    }

这将创建1个蓝星

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