CODEWITHSUNDEEP
iosobjective-ciphone
Yang Zecheng
Yang Zecheng

Reputation: 41

ios CGContextRef fill color

I want to draw an arc and fill it. The first picture is what it is. I want to get the effect of the second picture

The current

I want

- (id)initWithFrame:(CGRect)frame {
  if (self = [super initWithFrame:frame]) {
      // 必须清空背景色，不然绘制出来的区域之外有黑色背景
      [self setBackgroundColor:[UIColor clearColor]];
      [self setUserInteractionEnabled:NO];
  }
  return self;
}

- (void)drawRect:(CGRect)rect {
    float x = rect.origin.x;
    float y = rect.origin.y;
    float w = rect.size.width;
    float h = rect.size.height;
    CGContextRef context = UIGraphicsGetCurrentContext();
    UIColor *fullColor = [UIColor whiteColor];
    CGContextSetFillColorWithColor(context, fullColor.CGColor);
    CGContextSetRGBStrokeColor(context,1,1,1,1);
    CGContextMoveToPoint(context,0,h - 22);//圆弧的起始点
    CGContextAddQuadCurveToPoint(context, w / 2, h, w, h - 22);
    CGContextMoveToPoint(context,0,h - 22);//圆弧的起始点
    CGContextAddLineToPoint(context, 0, h);
    CGContextAddLineToPoint(context, w, h);
    CGContextAddLineToPoint(context, w, h - 22);

    CGContextStrokePath(context);
    CGContextDrawPath(context, kCGPathFillStroke);
}

Upvotes: 1

Views: 546

Answers (2)

Mats
Mats

Reputation: 8618

CGContextStrokePath() clears the current path. This also applies to CGContextDrawPath(), CGContextEOFillPath(), and, CGContextFillPath().

So when the call CGContextDrawPath(context, kCGPathFillStroke); is made, the current path in the context has just been cleared and is an empty path and nothing is drawn.

Removing the line CGContextStrokePath(context); just above should fix your issue.

Upvotes: 0

Yang Zecheng
Yang Zecheng

Reputation: 41

- (void)drawRect:(CGRect)rect {
   float x = rect.origin.x;
   float y = rect.origin.y;
   float w = rect.size.width;
   float h = rect.size.height;
   CGContextRef context = UIGraphicsGetCurrentContext();
   CGContextSetFillColorWithColor(context, [UIColor whiteColor].CGColor);
   CGContextFillRect(context, CGRectMake(0, h - 22, kScreenWidth , 22));
   CGContextSetFillColorWithColor(context, [UIColor clearColor].CGColor);
   // This method
   CGContextSetBlendMode(context, kCGBlendModeClear);
   CGContextMoveToPoint(context,0,h - 22);
   CGContextAddQuadCurveToPoint(context, w / 2, h + 14, w, h - 22);
   CGContextDrawPath(context, kCGPathFill);
   // This method
   CGContextSetBlendMode(context, kCGBlendModeNormal);
  }

I found a solution.

Upvotes: 1

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