drawRect - Draw Star

Question

我在視圖上繪製註釋。下面是我用來畫星的方法。

-(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); 

} 

我想只有明星的邊界刪除其他內部線是否有任何方法來實現這一目標？ （除了使用moveToPoint和addLine方法）

Answer 1

使用此代碼：

-(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); 
    } 

這將創建1藍星

Answer 2

您可以通過使用此代碼繪製星：

UIBezierPath* starPath = UIBezierPath.bezierPath; 
[starPath moveToPoint: CGPointMake(90, 31)]; 
[starPath addLineToPoint: CGPointMake(98.11, 42.06)]; 
[starPath addLineToPoint: CGPointMake(111.87, 45.86)]; 
[starPath addLineToPoint: CGPointMake(103.12, 56.49)]; 
[starPath addLineToPoint: CGPointMake(103.52, 69.89)]; 
[starPath addLineToPoint: CGPointMake(90, 65.4)]; 
[starPath addLineToPoint: CGPointMake(76.48, 69.89)]; 
[starPath addLineToPoint: CGPointMake(76.88, 56.49)]; 
[starPath addLineToPoint: CGPointMake(68.13, 45.86)]; 
[starPath addLineToPoint: CGPointMake(81.89, 42.06)]; 
[starPath closePath]; 
[UIColor.grayColor setFill]; 
[starPath fill];