气泡状path

-(CGPathRef)createPathWithArrowDirection:(MessageViewArrowDirection)direction AndRelativeOrigin:(CGPoint)reletiveOrigin
{

CGMutablePathRef path = CGPathCreateMutable();
CGRect rect;
if (reletiveOrigin.x<20) {
reletiveOrigin.x=20;
}
if (reletiveOrigin.x>self.bounds.size.width-20) {
reletiveOrigin.x=self.bounds.size.width-20 ;
}
if (reletiveOrigin.y<20) {
reletiveOrigin.y=20;
}
if (reletiveOrigin.y>self.bounds.size.height-20) {
reletiveOrigin.y=self.bounds.size.height-20 ;
}


if (direction==MessageViewArrowDirectionUp) {
rect=CGRectInset(self.bounds, 1, 10);
}
else if(direction==MessageViewArrowDirectionDown)
{
rect=CGRectInset(self.bounds, 1, 1);
rect.size.height=rect.size.height- 2*9;
}else if(direction==MessageViewArrowDirectionLeft)
{
rect=CGRectInset(self.bounds, 10, 1);
}
else if(direction==MessageViewArrowDirectionRight)
{
rect=CGRectInset(self.bounds, 1, 1);
rect.size.width=rect.size.width- 2*9;
}

CGFloat minx = CGRectGetMinX(rect), midx = CGRectGetMidX(rect), maxx = CGRectGetMaxX(rect);
CGFloat miny = CGRectGetMinY(rect), midy = CGRectGetMidY(rect), maxy = CGRectGetMaxY(rect);

CGFloat radius=10.0;
if (direction==MessageViewArrowDirectionUp) {

CGPathMoveToPoint(path, NULL, minx, midy);
CGPathAddArcToPoint(path, NULL, minx, miny, reletiveOrigin.x, miny, radius);
CGPathAddLineToPoint(path, NULL, reletiveOrigin.x, miny);
CGPathAddLineToPoint(path, NULL, reletiveOrigin.x+ARROW_WIDTH/2.0, 0);
CGPathAddLineToPoint(path, NULL, reletiveOrigin.x+ARROW_WIDTH, miny);
CGPathAddArcToPoint(path, NULL, maxx, miny, maxx, midy, radius);
CGPathAddArcToPoint(path, NULL, maxx, maxy, midx, maxy, radius);
CGPathAddArcToPoint(path, NULL, minx, maxy, minx, midy, radius);
}
else if(direction==MessageViewArrowDirectionDown)
{
CGPathMoveToPoint(path, NULL, minx, midy);
CGPathAddArcToPoint(path, NULL, minx, miny, midx, miny, radius);
CGPathAddArcToPoint(path, NULL, maxx, miny, maxx, midy, radius);
CGPathAddArcToPoint(path, NULL, maxx, maxy, reletiveOrigin.x+ARROW_WIDTH, maxy, radius);
CGPathAddLineToPoint(path, NULL, reletiveOrigin.x+ARROW_WIDTH, maxy);
CGPathAddLineToPoint(path, NULL, reletiveOrigin.x+ARROW_WIDTH/2.0, self.bounds.size.height);
CGPathAddLineToPoint(path, NULL, reletiveOrigin.x, maxy);
CGPathAddArcToPoint(path, NULL, minx, maxy, minx, midy, radius);
}else if(direction==MessageViewArrowDirectionLeft)
{
CGPathMoveToPoint(path, NULL, midx, miny);
CGPathAddArcToPoint(path, NULL, maxx, miny, maxx, midy, radius);
CGPathAddArcToPoint(path, NULL, maxx, maxy, midx, maxy, radius);
CGPathAddArcToPoint(path, NULL, minx, maxy, minx, reletiveOrigin.y+ARROW_HEIGHT, radius);
CGPathAddLineToPoint(path, NULL, minx, reletiveOrigin.y+ARROW_HEIGHT);
CGPathAddLineToPoint(path, NULL, self.bounds.origin.x, reletiveOrigin.y + ARROW_HEIGHT/2.0);
CGPathAddLineToPoint(path, NULL, minx, reletiveOrigin.y );
CGPathAddArcToPoint(path, NULL, minx, miny, midx, miny, radius);

}
else if(direction==MessageViewArrowDirectionRight)
{
CGPathMoveToPoint(path, NULL, minx, midy);
CGPathAddArcToPoint(path, NULL, minx, miny, midx, miny, radius);
CGPathAddArcToPoint(path, NULL, maxx, miny, maxx, reletiveOrigin.y, radius);
CGPathAddLineToPoint(path, NULL, maxx, reletiveOrigin.y);
CGPathAddLineToPoint(path, NULL, maxx+ARROW_WIDTH, reletiveOrigin.y+ARROW_HEIGHT/2.0);
CGPathAddLineToPoint(path, NULL, maxx, reletiveOrigin.y +ARROW_HEIGHT);
CGPathAddArcToPoint(path, NULL, maxx, maxy, midx, maxy, radius);
CGPathAddArcToPoint(path, NULL, minx, maxy, minx, midy, radius);
}

CGPathCloseSubpath(path);
return path;
}