needDrawStartEndPoint property

bool needDrawStartEndPoint

旋转渐变圆形进度条优化，避免在progress接近1时端点不显示半圆 起点半圆+圆弧+终点半圆

Implementation

bool get needDrawStartEndPoint {
  return linearGradient != null &&
      rotateLinearGradient &&
      progress != 0 &&
      strokeCap == StrokeCap.round &&
      arcType == ArcType.FULL &&
      maskFilter == null;
}