zulip/static/third/jquery-perfect-scrollbar/js/perfect-scrollbar.js

/* Copyright (c) 2012 HyeonJe Jun (http://github.com/noraesae)
 * Licensed under the MIT License
 */
'use strict';
(function (factory) {
  if (typeof define === 'function' && define.amd) {
    // AMD. Register as an anonymous module.
    define(['jquery'], factory);
  } else {
    // Browser globals
    factory(jQuery);
  }
}(function ($) {

  // The default settings for the plugin
  var defaultSettings = {
    wheelSpeed: 10,
    wheelPropagation: false,
    minScrollbarLength: null,
    useBothWheelAxes: false,
    useKeyboard: true,
    suppressScrollX: false,
    suppressScrollY: false,
    scrollXMarginOffset: 0,
    scrollYMarginOffset: 0
  };

  var getEventClassName = (function () {
    var incrementingId = 0;
    return function () {
      var id = incrementingId;
      incrementingId += 1;
      return '.perfect-scrollbar-' + id;
    };
  }());

  $.fn.perfectScrollbar = function (suppliedSettings, option) {

    return this.each(function () {
      // Use the default settings
      var settings = $.extend(true, {}, defaultSettings),
          $this = $(this);

      if (typeof suppliedSettings === "object") {
        // But over-ride any supplied
        $.extend(true, settings, suppliedSettings);
      } else {
        // If no settings were supplied, then the first param must be the option
        option = suppliedSettings;
      }

      // Catch options

      if (option === 'update') {
        if ($this.data('perfect-scrollbar-update')) {
          $this.data('perfect-scrollbar-update')();
        }
        return $this;
      }
      else if (option === 'destroy') {
        if ($this.data('perfect-scrollbar-destroy')) {
          $this.data('perfect-scrollbar-destroy')();
        }
        return $this;
      }

      if ($this.data('perfect-scrollbar')) {
        // if there's already perfect-scrollbar
        return $this.data('perfect-scrollbar');
      }


      // Or generate new perfectScrollbar

      // Set class to the container
      $this.addClass('ps-container');

      var $scrollbarXRail = $("<div class='ps-scrollbar-x-rail'></div>").appendTo($this),
          $scrollbarYRail = $("<div class='ps-scrollbar-y-rail'></div>").appendTo($this),
          $scrollbarX = $("<div class='ps-scrollbar-x'></div>").appendTo($scrollbarXRail),
          $scrollbarY = $("<div class='ps-scrollbar-y'></div>").appendTo($scrollbarYRail),
          scrollbarXActive,
          scrollbarYActive,
          containerWidth,
          containerHeight,
          contentWidth,
          contentHeight,
          scrollbarXWidth,
          scrollbarXLeft,
          scrollbarXBottom = parseInt($scrollbarXRail.css('bottom'), 10),
          scrollbarYHeight,
          scrollbarYTop,
          scrollbarYRight = parseInt($scrollbarYRail.css('right'), 10),
          eventClassName = getEventClassName();

      var updateContentScrollTop = function (currentTop, deltaY) {
        var newTop = currentTop + deltaY,
            maxTop = containerHeight - scrollbarYHeight;

        if (newTop < 0) {
          scrollbarYTop = 0;
        }
        else if (newTop > maxTop) {
          scrollbarYTop = maxTop;
        }
        else {
          scrollbarYTop = newTop;
        }

        var scrollTop = parseInt(scrollbarYTop * (contentHeight - containerHeight) / (containerHeight - scrollbarYHeight), 10);
        $this.scrollTop(scrollTop);
        $scrollbarXRail.css({bottom: scrollbarXBottom - scrollTop});
      };

      var updateContentScrollLeft = function (currentLeft, deltaX) {
        var newLeft = currentLeft + deltaX,
            maxLeft = containerWidth - scrollbarXWidth;

        if (newLeft < 0) {
          scrollbarXLeft = 0;
        }
        else if (newLeft > maxLeft) {
          scrollbarXLeft = maxLeft;
        }
        else {
          scrollbarXLeft = newLeft;
        }

        var scrollLeft = parseInt(scrollbarXLeft * (contentWidth - containerWidth) / (containerWidth - scrollbarXWidth), 10);
        $this.scrollLeft(scrollLeft);
        $scrollbarYRail.css({right: scrollbarYRight - scrollLeft});
      };

      var getSettingsAdjustedThumbSize = function (thumbSize) {
        if (settings.minScrollbarLength) {
          thumbSize = Math.max(thumbSize, settings.minScrollbarLength);
        }
        return thumbSize;
      };

      var updateScrollbarCss = function () {
        $scrollbarXRail.css({left: $this.scrollLeft(), bottom: scrollbarXBottom - $this.scrollTop(), width: containerWidth, display: scrollbarXActive ? "inherit": "none"});
        $scrollbarYRail.css({top: $this.scrollTop(), right: scrollbarYRight - $this.scrollLeft(), height: containerHeight, display: scrollbarYActive ? "inherit": "none"});
        $scrollbarX.css({left: scrollbarXLeft, width: scrollbarXWidth});
        $scrollbarY.css({top: scrollbarYTop, height: scrollbarYHeight});
      };

      var updateBarSizeAndPosition = function () {
        containerWidth = $this.width();
        containerHeight = $this.height();
        contentWidth = $this.prop('scrollWidth');
        contentHeight = $this.prop('scrollHeight');

        if (!settings.suppressScrollX && containerWidth + settings.scrollXMarginOffset < contentWidth) {
          scrollbarXActive = true;
          scrollbarXWidth = getSettingsAdjustedThumbSize(parseInt(containerWidth * containerWidth / contentWidth, 10));
          scrollbarXLeft = parseInt($this.scrollLeft() * (containerWidth - scrollbarXWidth) / (contentWidth - containerWidth), 10);
        }
        else {
          scrollbarXActive = false;
          scrollbarXWidth = 0;
          scrollbarXLeft = 0;
          $this.scrollLeft(0);
        }

        if (!settings.suppressScrollY && containerHeight + settings.scrollYMarginOffset < contentHeight) {
          scrollbarYActive = true;
          scrollbarYHeight = getSettingsAdjustedThumbSize(parseInt(containerHeight * containerHeight / contentHeight, 10));
          scrollbarYTop = parseInt($this.scrollTop() * (containerHeight - scrollbarYHeight) / (contentHeight - containerHeight), 10);
        }
        else {
          scrollbarYActive = false;
          scrollbarYHeight = 0;
          scrollbarYTop = 0;
          $this.scrollTop(0);
        }

        if (scrollbarYTop >= containerHeight - scrollbarYHeight) {
          scrollbarYTop = containerHeight - scrollbarYHeight;
        }
        if (scrollbarXLeft >= containerWidth - scrollbarXWidth) {
          scrollbarXLeft = containerWidth - scrollbarXWidth;
        }

        updateScrollbarCss();
      };

      var bindMouseScrollXHandler = function () {
        var currentLeft,
            currentPageX;

        $scrollbarX.bind('mousedown' + eventClassName, function (e) {
          currentPageX = e.pageX;
          currentLeft = $scrollbarX.position().left;
          $scrollbarXRail.addClass('in-scrolling');
          e.stopPropagation();
          e.preventDefault();
        });

        $(document).bind('mousemove' + eventClassName, function (e) {
          if ($scrollbarXRail.hasClass('in-scrolling')) {
            updateContentScrollLeft(currentLeft, e.pageX - currentPageX);
            e.stopPropagation();
            e.preventDefault();
          }
        });

        $(document).bind('mouseup' + eventClassName, function (e) {
          if ($scrollbarXRail.hasClass('in-scrolling')) {
            $scrollbarXRail.removeClass('in-scrolling');
          }
        });

        currentLeft =
        currentPageX = null;
      };

      var bindMouseScrollYHandler = function () {
        var currentTop,
            currentPageY;

        $scrollbarY.bind('mousedown' + eventClassName, function (e) {
          currentPageY = e.pageY;
          currentTop = $scrollbarY.position().top;
          $scrollbarYRail.addClass('in-scrolling');
          e.stopPropagation();
          e.preventDefault();
        });

        $(document).bind('mousemove' + eventClassName, function (e) {
          if ($scrollbarYRail.hasClass('in-scrolling')) {
            updateContentScrollTop(currentTop, e.pageY - currentPageY);
            e.stopPropagation();
            e.preventDefault();
          }
        });

        $(document).bind('mouseup' + eventClassName, function (e) {
          if ($scrollbarYRail.hasClass('in-scrolling')) {
            $scrollbarYRail.removeClass('in-scrolling');
          }
        });

        currentTop =
        currentPageY = null;
      };

      // check if the default scrolling should be prevented.
      var shouldPreventDefault = function (deltaX, deltaY) {
        var scrollTop = $this.scrollTop();
        if (deltaX === 0) {
          if (!scrollbarYActive) {
            return false;
          }
          if ((scrollTop === 0 && deltaY > 0) || (scrollTop >= contentHeight - containerHeight && deltaY < 0)) {
            return !settings.wheelPropagation;
          }
        }

        var scrollLeft = $this.scrollLeft();
        if (deltaY === 0) {
          if (!scrollbarXActive) {
            return false;
          }
          if ((scrollLeft === 0 && deltaX < 0) || (scrollLeft >= contentWidth - containerWidth && deltaX > 0)) {
            return !settings.wheelPropagation;
          }
        }
        return true;
      };

      // bind handlers
      var bindMouseWheelHandler = function () {
        var shouldPrevent = false;
        $this.bind('mousewheel' + eventClassName, function (e, deprecatedDelta, deprecatedDeltaX, deprecatedDeltaY) {
          var deltaX = e.deltaX ? e.deltaX / 10 : deprecatedDeltaX,
              deltaY = e.deltaY ? e.deltaY / 10 : deprecatedDeltaY;

          if (!settings.useBothWheelAxes) {
            // deltaX will only be used for horizontal scrolling and deltaY will
            // only be used for vertical scrolling - this is the default
            $this.scrollTop($this.scrollTop() - (deltaY * settings.wheelSpeed));
            $this.scrollLeft($this.scrollLeft() + (deltaX * settings.wheelSpeed));
          } else if (scrollbarYActive && !scrollbarXActive) {
            // only vertical scrollbar is active and useBothWheelAxes option is
            // active, so let's scroll vertical bar using both mouse wheel axes
            if (deltaY) {
              $this.scrollTop($this.scrollTop() - (deltaY * settings.wheelSpeed));
            } else {
              $this.scrollTop($this.scrollTop() + (deltaX * settings.wheelSpeed));
            }
          } else if (scrollbarXActive && !scrollbarYActive) {
            // useBothWheelAxes and only horizontal bar is active, so use both
            // wheel axes for horizontal bar
            if (deltaX) {
              $this.scrollLeft($this.scrollLeft() + (deltaX * settings.wheelSpeed));
            } else {
              $this.scrollLeft($this.scrollLeft() - (deltaY * settings.wheelSpeed));
            }
          }

          // update bar position
          updateBarSizeAndPosition();

          shouldPrevent = shouldPreventDefault(deltaX, deltaY);
          if (shouldPrevent) {
            e.preventDefault();
          }
        });

        // fix Firefox scroll problem
        $this.bind('MozMousePixelScroll' + eventClassName, function (e) {
          if (shouldPrevent) {
            e.preventDefault();
          }
        });
      };

      var bindKeyboardHandler = function () {
        var hovered = false;
        $this.bind('mouseenter' + eventClassName, function (e) {
          hovered = true;
        });
        $this.bind('mouseleave' + eventClassName, function (e) {
          hovered = false;
        });

        var shouldPrevent = false;
        $(document).bind('keydown' + eventClassName, function (e) {
          if (!hovered || $(document.activeElement).is(":input,[contenteditable]")) {
            return;
          }

          var deltaX = 0,
              deltaY = 0;

          switch (e.which) {
          case 37: // left
            deltaX = -3;
            break;
          case 38: // up
            deltaY = 3;
            break;
          case 39: // right
            deltaX = 3;
            break;
          case 40: // down
            deltaY = -3;
            break;
          case 33: // page up
            deltaY = 9;
            break;
          case 32: // space bar
          case 34: // page down
            deltaY = -9;
            break;
          case 35: // end
            deltaY = -containerHeight;
            break;
          case 36: // home
            deltaY = containerHeight;
            break;
          default:
            return;
          }

          $this.scrollTop($this.scrollTop() - (deltaY * settings.wheelSpeed));
          $this.scrollLeft($this.scrollLeft() + (deltaX * settings.wheelSpeed));

          shouldPrevent = shouldPreventDefault(deltaX, deltaY);
          if (shouldPrevent) {
            e.preventDefault();
          }
        });
      };

      var bindRailClickHandler = function () {
        var stopPropagation = function (e) { e.stopPropagation(); };

        $scrollbarY.bind('click' + eventClassName, stopPropagation);
        $scrollbarYRail.bind('click' + eventClassName, function (e) {
          var halfOfScrollbarLength = parseInt(scrollbarYHeight / 2, 10),
              positionTop = e.pageY - $scrollbarYRail.offset().top - halfOfScrollbarLength,
              maxPositionTop = containerHeight - scrollbarYHeight,
              positionRatio = positionTop / maxPositionTop;

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

          $this.scrollTop((contentHeight - containerHeight) * positionRatio);
        });

        $scrollbarX.bind('click' + eventClassName, stopPropagation);
        $scrollbarXRail.bind('click' + eventClassName, function (e) {
          var halfOfScrollbarLength = parseInt(scrollbarXWidth / 2, 10),
              positionLeft = e.pageX - $scrollbarXRail.offset().left - halfOfScrollbarLength,
              maxPositionLeft = containerWidth - scrollbarXWidth,
              positionRatio = positionLeft / maxPositionLeft;

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

          $this.scrollLeft((contentWidth - containerWidth) * positionRatio);
        });
      };

      // bind mobile touch handler
      var bindMobileTouchHandler = function () {
        var applyTouchMove = function (differenceX, differenceY) {
          $this.scrollTop($this.scrollTop() - differenceY);
          $this.scrollLeft($this.scrollLeft() - differenceX);

          // update bar position
          updateBarSizeAndPosition();
        };

        var startCoords = {},
            startTime = 0,
            speed = {},
            breakingProcess = null,
            inGlobalTouch = false;

        $(window).bind("touchstart" + eventClassName, function (e) {
          inGlobalTouch = true;
        });
        $(window).bind("touchend" + eventClassName, function (e) {
          inGlobalTouch = false;
        });

        $this.bind("touchstart" + eventClassName, function (e) {
          var touch = e.originalEvent.targetTouches[0];

          startCoords.pageX = touch.pageX;
          startCoords.pageY = touch.pageY;

          startTime = (new Date()).getTime();

          if (breakingProcess !== null) {
            clearInterval(breakingProcess);
          }

          e.stopPropagation();
        });
        $this.bind("touchmove" + eventClassName, function (e) {
          if (!inGlobalTouch && e.originalEvent.targetTouches.length === 1) {
            var touch = e.originalEvent.targetTouches[0];

            var currentCoords = {};
            currentCoords.pageX = touch.pageX;
            currentCoords.pageY = touch.pageY;

            var differenceX = currentCoords.pageX - startCoords.pageX,
              differenceY = currentCoords.pageY - startCoords.pageY;

            applyTouchMove(differenceX, differenceY);
            startCoords = currentCoords;

            var currentTime = (new Date()).getTime();

            var timeGap = currentTime - startTime;
            if (timeGap > 0) {
              speed.x = differenceX / timeGap;
              speed.y = differenceY / timeGap;
              startTime = currentTime;
            }

            e.preventDefault();
          }
        });
        $this.bind("touchend" + eventClassName, function (e) {
          clearInterval(breakingProcess);
          breakingProcess = setInterval(function () {
            if (Math.abs(speed.x) < 0.01 && Math.abs(speed.y) < 0.01) {
              clearInterval(breakingProcess);
              return;
            }

            applyTouchMove(speed.x * 30, speed.y * 30);

            speed.x *= 0.8;
            speed.y *= 0.8;
          }, 10);
        });
      };

      var bindScrollHandler = function () {
        $this.bind('scroll' + eventClassName, function (e) {
          updateBarSizeAndPosition();
        });
      };

      var destroy = function () {
        $this.unbind(eventClassName);
        $(window).unbind(eventClassName);
        $(document).unbind(eventClassName);
        $this.data('perfect-scrollbar', null);
        $this.data('perfect-scrollbar-update', null);
        $this.data('perfect-scrollbar-destroy', null);
        $scrollbarX.remove();
        $scrollbarY.remove();
        $scrollbarXRail.remove();
        $scrollbarYRail.remove();

        // clean all variables
        $scrollbarX =
        $scrollbarY =
        containerWidth =
        containerHeight =
        contentWidth =
        contentHeight =
        scrollbarXWidth =
        scrollbarXLeft =
        scrollbarXBottom =
        scrollbarYHeight =
        scrollbarYTop =
        scrollbarYRight = null;
      };

      var ieSupport = function (version) {
        $this.addClass('ie').addClass('ie' + version);

        var bindHoverHandlers = function () {
          var mouseenter = function () {
            $(this).addClass('hover');
          };
          var mouseleave = function () {
            $(this).removeClass('hover');
          };
          $this.bind('mouseenter' + eventClassName, mouseenter).bind('mouseleave' + eventClassName, mouseleave);
          $scrollbarXRail.bind('mouseenter' + eventClassName, mouseenter).bind('mouseleave' + eventClassName, mouseleave);
          $scrollbarYRail.bind('mouseenter' + eventClassName, mouseenter).bind('mouseleave' + eventClassName, mouseleave);
          $scrollbarX.bind('mouseenter' + eventClassName, mouseenter).bind('mouseleave' + eventClassName, mouseleave);
          $scrollbarY.bind('mouseenter' + eventClassName, mouseenter).bind('mouseleave' + eventClassName, mouseleave);
        };

        var fixIe6ScrollbarPosition = function () {
          updateScrollbarCss = function () {
            $scrollbarX.css({left: scrollbarXLeft + $this.scrollLeft(), bottom: scrollbarXBottom, width: scrollbarXWidth});
            $scrollbarY.css({top: scrollbarYTop + $this.scrollTop(), right: scrollbarYRight, height: scrollbarYHeight});
            $scrollbarX.hide().show();
            $scrollbarY.hide().show();
          };
        };

        if (version === 6) {
          bindHoverHandlers();
          fixIe6ScrollbarPosition();
        }
      };

      var supportsTouch = (('ontouchstart' in window) || window.DocumentTouch && document instanceof window.DocumentTouch);

      var initialize = function () {
        var ieMatch = navigator.userAgent.toLowerCase().match(/(msie) ([\w.]+)/);
        if (ieMatch && ieMatch[1] === 'msie') {
          // must be executed at first, because 'ieSupport' may addClass to the container
          ieSupport(parseInt(ieMatch[2], 10));
        }

        updateBarSizeAndPosition();
        bindScrollHandler();
        bindMouseScrollXHandler();
        bindMouseScrollYHandler();
        bindRailClickHandler();
        if (supportsTouch) {
          bindMobileTouchHandler();
        }
        if ($this.mousewheel) {
          bindMouseWheelHandler();
        }
        if (settings.useKeyboard) {
          bindKeyboardHandler();
        }
        $this.data('perfect-scrollbar', $this);
        $this.data('perfect-scrollbar-update', updateBarSizeAndPosition);
        $this.data('perfect-scrollbar-destroy', destroy);
      };

      // initialize
      initialize();

      return $this;
    });
  };
}));