多行文字的对齐方式

enum AttachmentPoint {
  kTopLeft = 1,
  kTopCenter = 2,
  kTopRight = 3,
  kMiddleLeft = 4,
  kMiddleCenter = 5,
  kMiddleRight = 6,
  kBottomLeft = 7,
  kBottomCenter = 8,
  kBottomRight = 9,
  kBaseLeft = 10,
  kBaseCenter = 11,
  kBaseRight = 12,
  kBaseAlign = 13,
  kBottomAlign = 14,
  kMiddleAlign = 15,
  kTopAlign = 16,
  kBaseFit = 17,
  kBottomFit = 18,
  kMiddleFit = 19,
  kTopFit = 20,
  kBaseMid = 21,
  kBottomMid = 22,
  kMiddleMid = 23,
  kTopMid = 24
};