bmfe-vue2-base/src/js/baseLibs/sidebarMenu/perfectScrollbar/plugin/handler/click-rail.js

BM 后台系统基础框架

'use strict';

var _ = require('../../lib/helper');
var instances = require('../instances');
var updateGeometry = require('../update-geometry');
var updateScroll = require('../update-scroll');

function bindClickRailHandler(element, i) {
  function pageOffset(el) {
    return el.getBoundingClientRect();
  }
  var stopPropagation = function (e) { e.stopPropagation(); };

  if (i.settings.stopPropagationOnClick) {
    i.event.bind(i.scrollbarY, 'click', stopPropagation);
  }
  i.event.bind(i.scrollbarYRail, 'click', function (e) {
    var halfOfScrollbarLength = _.toInt(i.scrollbarYHeight / 2);
    var positionTop = i.railYRatio * (e.pageY - window.pageYOffset - pageOffset(i.scrollbarYRail).top - halfOfScrollbarLength);
    var maxPositionTop = i.railYRatio * (i.railYHeight - i.scrollbarYHeight);
    var positionRatio = positionTop / maxPositionTop;

    if (positionRatio < 0) {
      positionRatio = 0;
    } else if (positionRatio > 1) {
      positionRatio = 1;
    }

    updateScroll(element, 'top', (i.contentHeight - i.containerHeight) * positionRatio);
    updateGeometry(element);

    e.stopPropagation();
  });

  if (i.settings.stopPropagationOnClick) {
    i.event.bind(i.scrollbarX, 'click', stopPropagation);
  }
  i.event.bind(i.scrollbarXRail, 'click', function (e) {
    var halfOfScrollbarLength = _.toInt(i.scrollbarXWidth / 2);
    var positionLeft = i.railXRatio * (e.pageX - window.pageXOffset - pageOffset(i.scrollbarXRail).left - halfOfScrollbarLength);
    var maxPositionLeft = i.railXRatio * (i.railXWidth - i.scrollbarXWidth);
    var positionRatio = positionLeft / maxPositionLeft;

    if (positionRatio < 0) {
      positionRatio = 0;
    } else if (positionRatio > 1) {
      positionRatio = 1;
    }

    updateScroll(element, 'left', ((i.contentWidth - i.containerWidth) * positionRatio) - i.negativeScrollAdjustment);
    updateGeometry(element);

    e.stopPropagation();
  });
}

module.exports = function (element) {
  var i = instances.get(element);
  bindClickRailHandler(element, i);
};