CGContext 绘画简单的聊天框

圆弧画法

  CGContextMoveToPoint(context, point3.x, point3.y);  
  CGContextAddArcToPoint(context,point4.x, point4.y,point5.x, point5.y,6.0);

point3 起点 point4 拐点  point5 终点

聊天框 完整代码

- (void)drawRect:(CGRect)rect {

    // Drawing code

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetStrokeColorWithColor(context, [UIColor secondaryLabelColor].CGColor);//线条颜色

    CGContextSetLineWidth(context, 1.0);//线条宽度

    CGContextBeginPath(context);

    CGFloatpointX =100;

    CGPointpoint1 =CGPointMake(pointX,Triangleheight);

    CGPointpoint2 =CGPointMake(pointX+TriangleWidth/2,0);

    CGPoint point3 = CGPointMake(pointX+TriangleWidth, Triangleheight);

    CGPoint point4 = CGPointMake(self.bounds.size.width-1, Triangleheight);

    CGPoint point5 = CGPointMake(self.bounds.size.width-1, self.bounds.size.height-1);

    CGPoint point6 = CGPointMake(1, self.bounds.size.height-1);

    CGPointpoint7 =CGPointMake(1,Triangleheight);

    CGContextMoveToPoint(context, point1.x, point1.y);

    CGContextAddLineToPoint(context, point2.x, point2.y);

    CGContextAddLineToPoint(context, point3.x, point3.y);

    CGContextAddArcToPoint(context,point4.x, point4.y,point5.x, point5.y,6.0);

    CGContextAddArcToPoint(context,point5.x, point5.y, point6.x, point6.y,6.0);

    CGContextAddArcToPoint(context,point6.x, point6.y, point7.x, point7.y,6.0);

    CGContextAddArcToPoint(context,point7.x, point7.y, point1.x, point1.y,6.0);

    CGContextAddLineToPoint(context, point1.x, point1.y);

    CGContextStrokePath(context);

}