(PECL haru >= 0.0.1)
HaruPage::circle — Append a circle to the current path
$x
   , float $y
   , float $ray
   )Appends a circle to the current path.
xHorizontal coordinate of the center point.
yVertical coordinate of the center point.
rayThe ray of the circle.
   Returns TRUE on success.
  
发生错误时抛出 HaruException 异常。