繪制不同的線條

• 畫矩形

  - (void)drawRect:(CGRect)rect
  {
      // 使用BezierPath進行繪制
      UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(50, 50, 110, 120)];
      [path stroke];
  }
  

• 圓角矩形

  - (void)drawRect:(CGRect)rect
  {
      // 使用BezierPath進行繪制
      UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(50, 50, 110, 120)];
      [path stroke];
  }
  

• 橢圓的畫法

  // C語言的方式
  - (void)drawRect:(CGRect)rect
  {
      // 獲取上下文
     CGContextRef ctx = UIGraphicsGetCurrentContext();
      // 在rect區域內進行橢圓繪制
      CGContextAddEllipseInRect(ctx, CGRectMake(50, 50, 150, 50));
      // 繪制
      CGContextStrokePath(ctx);
  }
  // OC方法
  - (void)drawRect:(CGRect)rect
  {
      // 使用BezierPath進行繪制
      UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(50, 50, 160, 60)];
      [path stroke];
  }
  

• 圓弧的畫法

  // c的方式
  - (void)drawRect:(CGRect)rect
  {
      // 圓弧
      CGContextRef ctx = UIGraphicsGetCurrentContext();
      CGContextAddArc(ctx, 50, 50, 50, 0, M_PI * 2, YES);
      CGContextStrokePath(ctx);
  }
  // OC的方式
  - (void)drawRect:(CGRect)rect
  {
      UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(100, 100) radius:50 startAngle:0 endAngle:M_PI clockwise:YES];
      [path stroke];
  }
  

• 五角星的畫法

  - (void)drawRect:(CGRect)rect
  {
      UIBezierPath* path = [UIBezierPath bezierPath];
  
      NSMutableArray *arrs = [NSMutableArray array];
  
      for (int i = 0; i< 5; i++) {
  
          CGFloat start = (3 * M_PI_2) + (i * M_PI * 2 / 5);
          CGFloat end = (start + M_PI * 2 / 5 * 2) + (i * M_PI * 2 / 5);
  
          [path addArcWithCenter:CGPointMake(150, 150) radius:100 startAngle:start endAngle:end clockwise:YES];
          CGPoint point =  [path currentPoint];
          NSValue *value = [NSValue valueWithCGPoint:point];
  
          [arrs addObject:value];
      }
  
      UIBezierPath *p = [UIBezierPath bezierPath];
  
      for (int i = 0; i< arrs.count; i++) {
          if (i == arrs.count - 1) {
              [[UIColor redColor]set];
              CGPoint point = [arrs[i] CGPointValue];
              [p moveToPoint:point];
              [p addLineToPoint:[arrs[0] CGPointValue]];
              [p stroke];
  
              return;
          }
  
          CGPoint start = [arrs[i] CGPointValue];
          [p moveToPoint:start];
          CGPoint end = [arrs[i+1] CGPointValue];
          [p addLineToPoint:end];
          [p stroke];
      }
  
  }