arc 方法

void arc(
  1. num x,
  2. num y,
  3. num radius,
  4. num startAngle,
  5. num endAngle,
  6. [bool anticlockwise = false]
)

实现

void arc(num x, num y, num radius, num startAngle, num endAngle,
    [bool anticlockwise = false]) {
  // TODO(terry): This should not be needed: dartbug.com/20939.
  JS('void', '#.arc(#, #, #, #, #, #)', this, x, y, radius, startAngle,
      endAngle, anticlockwise);
}