perfect-scrollbar/src/perfect-scrollbar.js

/* Copyright (c) 2012 HyeonJe Jun (http://github.com/noraesae)
 * Licensed under the MIT License
 */
((function ($) {

  // The default settings for the plugin
  var defaultSettings = {
    wheelSpeed: 10,
    wheelPropagation: false
  };

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

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

      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');
      }

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

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

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

      var updateBarSizeAndPosition = function () {
        containerWidth = $this.width();
        containerHeight = $this.height();
        contentWidth = $this.prop('scrollWidth');
        contentHeight = $this.prop('scrollHeight');
        if (containerWidth < contentWidth) {
          scrollbarXWidth = parseInt(containerWidth * containerWidth / contentWidth, 10);
          scrollbarXLeft = parseInt($this.scrollLeft() * containerWidth / contentWidth, 10);
        }
        else {
          scrollbarXWidth = 0;
          scrollbarXLeft = 0;
          $this.scrollLeft(0);
        }
        if (containerHeight < contentHeight) {
          scrollbarYHeight = parseInt(containerHeight * containerHeight / contentHeight, 10);
          scrollbarYTop = parseInt($this.scrollTop() * containerHeight / contentHeight, 10);
        }
        else {
          scrollbarYHeight = 0;
          scrollbarYTop = 0;
          $this.scrollTop(0);
        }

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

        $scrollbarX.css({left: scrollbarXLeft + $this.scrollLeft(), bottom: scrollbarXBottom - $this.scrollTop(), width: scrollbarXWidth});
        $scrollbarY.css({top: scrollbarYTop + $this.scrollTop(), right: scrollbarYRight - $this.scrollLeft(), height: scrollbarYHeight});
      };

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

        if (newLeft < 0) {
          scrollbarXLeft = 0;
        }
        else if (newLeft > maxLeft) {
          scrollbarXLeft = maxLeft;
        }
        else {
          scrollbarXLeft = newLeft;
        }
        $scrollbarX.css({left: scrollbarXLeft + $this.scrollLeft()});
      };

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

        if (newTop < 0) {
          scrollbarYTop = 0;
        }
        else if (newTop > maxTop) {
          scrollbarYTop = maxTop;
        }
        else {
          scrollbarYTop = newTop;
        }
        $scrollbarY.css({top: scrollbarYTop + $this.scrollTop()});
      };

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

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

        $(document).bind('mousemove.perfect-scroll', function (e) {
          if ($scrollbarX.hasClass('in-scrolling')) {
            updateContentScrollLeft();
            moveBarX(currentLeft, e.pageX - currentPageX);
            e.stopPropagation();
            e.preventDefault();
          }
        });

        $(document).bind('mouseup.perfect-scroll', function (e) {
          if ($scrollbarX.hasClass('in-scrolling')) {
            $scrollbarX.removeClass('in-scrolling');
          }
        });
      };

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

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

        $(document).bind('mousemove.perfect-scroll', function (e) {
          if ($scrollbarY.hasClass('in-scrolling')) {
            updateContentScrollTop();
            moveBarY(currentTop, e.pageY - currentPageY);
            e.stopPropagation();
            e.preventDefault();
          }
        });

        $(document).bind('mouseup.perfect-scroll', function (e) {
          if ($scrollbarY.hasClass('in-scrolling')) {
            $scrollbarY.removeClass('in-scrolling');
          }
        });
      };

      // bind handlers
      var bindMouseWheelHandler = function () {
        var shouldPreventDefault = function (deltaX, deltaY) {
          var scrollTop = $this.scrollTop();
          if (scrollTop === 0 && deltaY > 0 && deltaX === 0) {
            return !settings.wheelPropagation;
          }
          else if (scrollTop >= contentHeight - containerHeight && deltaY < 0 && deltaX === 0) {
            return !settings.wheelPropagation;
          }

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

        $this.bind('mousewheel.perfect-scroll', function (e, delta, deltaX, deltaY) {
          $this.scrollTop($this.scrollTop() - (deltaY * settings.wheelSpeed));
          $this.scrollLeft($this.scrollLeft() + (deltaX * settings.wheelSpeed));

          // update bar position
          updateBarSizeAndPosition();

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

      // 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.perfect-scroll", function (e) {
          inGlobalTouch = true;
        });
        $(window).bind("touchend.perfect-scroll", function (e) {
          inGlobalTouch = false;
        });

        $this.bind("touchstart.perfect-scroll", 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.perfect-scroll", 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();
            speed.x = differenceX / (currentTime - startTime);
            speed.y = differenceY / (currentTime - startTime);
            startTime = currentTime;

            e.preventDefault();
          }
        });
        $this.bind("touchend.perfect-scroll", function (e) {
          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 destroy = function () {
        $scrollbarX.remove();
        $scrollbarY.remove();
        $this.unbind('.perfect-scroll');
        $(window).unbind('.perfect-scroll');
        $this.data('perfect-scrollbar', null);
        $this.data('perfect-scrollbar-update', null);
        $this.data('perfect-scrollbar-destroy', null);
      };

      var isMobile = /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent);

      var initialize = function () {
        updateBarSizeAndPosition();
        bindMouseScrollXHandler();
        bindMouseScrollYHandler();
        if (isMobile) {
          bindMobileTouchHandler();
        }
        if ($this.mousewheel) {
          bindMouseWheelHandler();
        }
        $this.data('perfect-scrollbar', $this);
        $this.data('perfect-scrollbar-update', updateBarSizeAndPosition);
        $this.data('perfect-scrollbar-destroy', destroy);
      };

      // initialize
      initialize();

      return $this;
    });
  };
})(jQuery));