拖放过程中的光标类型

enum CursorType {
  kNoSpecialCursor = -1,
  kCrosshair = 0,
  kRectCursor,
  kRubberBand,
  kNotRotated,
  kTargetBox,
  kRotatedCrosshair,
  kCrosshairNoRotate,
  kInvisible,
  kEntitySelect,
  kParallelogram,
  kEntitySelectNoPersp,
  kPkfirstOrGrips,
  kCrosshairDashed,
  kPointCursor
};