import "BaccaratGameBubbleView.h"

@implementation BaccaratGameBubbleView

// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.

• (void)drawRect:(CGRect)rect {
  [super drawRect:rect];

CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGMutablePathRef contourPath = CGPathCreateMutable();

CGFloat x = rect.size.width/2;
CGFloat y = rect.size.height;
CGFloat arrowWidth = 10.0f;
CGFloat arrowHeight = 5.0f;
CGFloat cornerRadius = 4.0f;

CGRect bubbleFrame = CGRectMake(0, 0, rect.size.width, rect.size.height-arrowHeight);

CGPathMoveToPoint(contourPath, NULL, x, y);
CGPathAddLineToPoint(contourPath, NULL, x - arrowWidth / 2, y + (-1) * arrowHeight);

[self drawBubbleBottomShapeWithFrame:bubbleFrame cornerRadius:cornerRadius path:contourPath];

CGPathAddLineToPoint(contourPath, NULL, x + (arrowWidth/2), y - arrowHeight);


CGPathCloseSubpath(contourPath);

CGContextAddPath(context, contourPath);
CGContextClip(context);

// 填充内部颜色
CGContextSetFillColorWithColor(context, [[UIColor blackColor] colorWithAlphaComponent:0.65].CGColor);
CGContextFillRect(context, CGRectMake(0, 0, rect.size.width, rect.size.height));

[self drawBorderWithBorderPath:contourPath context:context];
CGContextRestoreGState(context);

}

• (void)drawBorderWithBorderPath:(CGMutablePathRef)borderPath context:(CGContextRef)context {
  // 设置画笔颜色
  CGContextAddPath(context, borderPath);
  CGContextSetStrokeColorWithColor(context, [[UIColor whiteColor] colorWithAlphaComponent:0.75].CGColor);
  CGContextSetLineWidth(context, 2);
  CGContextStrokePath(context);
  }

• (void)drawBubbleBottomShapeWithFrame:(CGRect)frame cornerRadius:(CGFloat)cornerRadius path:(CGMutablePathRef)path {
  CGPathAddArcToPoint(path, NULL, frame.origin.x, frame.origin.y+frame.size.height, frame.origin.x, frame.origin.y, cornerRadius);
  CGPathAddArcToPoint(path, NULL, frame.origin.x, frame.origin.y, frame.origin.x+frame.size.width, frame.origin.y, cornerRadius);
  CGPathAddArcToPoint(path, NULL, frame.origin.x + frame.size.width, frame.origin.y, frame.origin.x+frame.size.width, frame.origin.y+frame.size.height, cornerRadius);
  CGPathAddArcToPoint(path, NULL, frame.origin.x + frame.size.width, frame.origin.y + frame.size.height, frame.origin.x, frame.origin.y+frame.size.height, cornerRadius);
  }

https://blog.csdn.net/samuelandkevin/article/details/121580726