code: private void resetPadding() {
          int[] padding = new int[4];
          System.arraycopy(this.padding, 0, padding, 0, 4);
          switch (arrowSide) {
              case RIGHT_BOTTOM:
              case RIGHT_MIDDLE:
              case RIGHT_TOP:
                  padding[2] += arrowHeight;
                  break;
              case LEFT_BOTTOM:
              case LEFT_MIDDLE:
              case LEFT_TOP:
                  padding[0] += arrowHeight;
                  break;
              case TOP_MIDDLE:
              case TOP_LEFT:
              case TOP_RIGHT:
                  padding[1] += arrowHeight;
                  break;
              case BOTTOM_CENTER:
              case BOTTOM_LEFT:
              case BOTTOM_RIGHT:
                  padding[3] += arrowHeight;
                  break;
          }
          setPadding(padding[0], padding[1], padding[2], padding[3]);
      }
docs: 根据箭头的方位不同，设置不同的padding