cursor.js

Handles the shared cursors, display and capturing the events. Also handles clicks and scrolls. Includes UI.

  • /* This Source Code Form is subject to the terms of the Mozilla Public
     * License, v. 2.0. If a copy of the MPL was not distributed with this file,
     * You can obtain one at http://mozilla.org/MPL/2.0/. */
  • Cursor viewing support

    define(["jquery", "ui", "util", "session", "elementFinder", "tinycolor", "eventMaker", "peers", "templating"], function ($, ui, util, session, elementFinder, tinycolor, eventMaker, peers, templating) {
      var assert = util.assert;
      var cursor = util.Module("cursor");
    
      var FOREGROUND_COLORS = ["#111", "#eee"];
      var CURSOR_HEIGHT = 50;
      var CURSOR_ANGLE = (35 / 180) * Math.PI;
      var CURSOR_WIDTH = Math.ceil(Math.sin(CURSOR_ANGLE) * CURSOR_HEIGHT);
  • Number of milliseconds after page load in which a scroll-update related hello-back message will be processed:

      var SCROLL_UPDATE_CUTOFF = 2000;
    
      session.hub.on("cursor-update", function (msg) {
        if (msg.sameUrl) {
          Cursor.getClient(msg.clientId).updatePosition(msg);
        } else {
  • FIXME: This should be caught even before the cursor-update message, when the peer goes to another URL

          Cursor.getClient(msg.clientId).hideOtherUrl();
        }
      });
  • FIXME: should check for a peer leaving and remove the cursor object

      var Cursor = util.Class({
    
        constructor: function (clientId) {
          this.clientId = clientId;
          this.element = templating.clone("cursor");
          this.elementClass = "togetherjs-scrolled-normal";
          this.element.addClass(this.elementClass);
          this.updatePeer(peers.getPeer(clientId));
          this.lastTop = this.lastLeft = null;
          $(document.body).append(this.element);
          this.element.animateCursorEntry();
          this.keydownTimeout = null;
          this.clearKeydown = this.clearKeydown.bind(this);
          this.atOtherUrl = false;
        },
  • How long after receiving a setKeydown call that we should show the user typing. This should be more than MIN_KEYDOWN_TIME:

        KEYDOWN_WAIT_TIME: 2000,
    
        updatePeer: function (peer) {
  • FIXME: can I use peer.setElement()?

          this.element.css({color: peer.color});
          var img = this.element.find("img.togetherjs-cursor-img");
          img.attr("src", makeCursor(peer.color));
          var name = this.element.find(".togetherjs-cursor-name");
          var nameContainer = this.element.find(".togetherjs-cursor-container");
          assert(name.length);
          name.text(peer.name);
          nameContainer.css({
            backgroundColor: peer.color,
            color: tinycolor.mostReadable(peer.color, FOREGROUND_COLORS)
          });
          var path = this.element.find("svg path");
          path.attr("fill", peer.color);
  • FIXME: should I just remove the element?

          if (peer.status != "live") {
  • this.element.hide();

            this.element.find("svg").animate({
              opacity: 0
            }, 350);
            this.element.find(".togetherjs-cursor-container").animate({
                    width: 34,
                    height: 20,
                    padding: 12,
                    margin: 0
                }, 200).animate({
                    width: 0,
                    height: 0,
                    padding: 0,
                    opacity: 0
                    }, 200);
          } else {
  • this.element.show();

            this.element.animate({
              opacity:0.3
            }).animate({
              opacity:1
            });
          }
        },
    
        setClass: function (name) {
          if (name != this.elementClass) {
            this.element.removeClass(this.elementClass).addClass(name);
            this.elementClass = name;
          }
        },
    
        updatePosition: function (pos) {
          var top, left;
          if (this.atOtherUrl) {
            this.element.show();
            this.atOtherUrl = false;
          }
          if (pos.element) {
            var target = $(elementFinder.findElement(pos.element));
            var offset = target.offset();
            top = offset.top + pos.offsetY;
            left = offset.left + pos.offsetX;
          } else {
  • No anchor, just an absolute position

            top = pos.top;
            left = pos.left;
          }
  • These are saved for use by .refresh():

          this.lastTop = top;
          this.lastLeft = left;
          this.setPosition(top, left);
        },
    
        hideOtherUrl: function () {
          if (this.atOtherUrl) {
            return;
          }
          this.atOtherUrl = true;
  • FIXME: should show away status better:

          this.element.hide();
        },
  • place Cursor rotate function down here FIXME: this doesnt do anything anymore. This is in the CSS as an animation

        rotateCursorDown: function(){
          var e = $(this.element).find('svg');
            e.animate({borderSpacing: -150, opacity: 1}, {
            step: function(now, fx) {
              if (fx.prop == "borderSpacing") {
                e.css('-webkit-transform', 'rotate('+now+'deg)')
                  .css('-moz-transform', 'rotate('+now+'deg)')
                  .css('-ms-transform', 'rotate('+now+'deg)')
                  .css('-o-transform', 'rotate('+now+'deg)')
                  .css('transform', 'rotate('+now+'deg)');
              } else {
                e.css(fx.prop, now);
              }
            },
            duration: 500
          }, 'linear').promise().then(function () {
            e.css('-webkit-transform', '')
              .css('-moz-transform', '')
              .css('-ms-transform', '')
              .css('-o-transform', '')
              .css('transform', '')
              .css("opacity", "");
          });
        },
    
        setPosition: function (top, left) {
          var wTop = $(window).scrollTop();
          var height = $(window).height();
    
          if (top < wTop) {
  • FIXME: this is a totally arbitrary number, but is meant to be big enough to keep the cursor name from being off the top of the screen.

            top = 25;
            this.setClass("togetherjs-scrolled-above");
          } else if (top > wTop + height - CURSOR_HEIGHT) {
            top = height - CURSOR_HEIGHT - 5;
            this.setClass("togetherjs-scrolled-below");
          } else {
            this.setClass("togetherjs-scrolled-normal");
          }
          this.element.css({
            top: top,
            left: left
          });
        },
    
        refresh: function () {
          if (this.lastTop !== null) {
            this.setPosition(this.lastTop, this.lastLeft);
          }
        },
    
        setKeydown: function () {
          if (this.keydownTimeout) {
            clearTimeout(this.keydownTimeout);
          } else {
            this.element.find(".togetherjs-cursor-typing").show().animateKeyboard();
          }
          this.keydownTimeout = setTimeout(this.clearKeydown, this.KEYDOWN_WAIT_TIME);
        },
    
        clearKeydown: function () {
          this.keydownTimeout = null;
          this.element.find(".togetherjs-cursor-typing").hide().stopKeyboardAnimation();
        },
    
        _destroy: function () {
          this.element.remove();
          this.element = null;
        }
      });
    
      Cursor._cursors = {};
    
      cursor.getClient = Cursor.getClient = function (clientId) {
        var c = Cursor._cursors[clientId];
        if (! c) {
          c = Cursor._cursors[clientId] = Cursor(clientId);
        }
        return c;
      };
    
      Cursor.forEach = function (callback, context) {
        context = context || null;
        for (var a in Cursor._cursors) {
          if (Cursor._cursors.hasOwnProperty(a)) {
            callback.call(context, Cursor._cursors[a], a);
          }
        }
      };
    
      Cursor.destroy = function (clientId) {
        Cursor._cursors[clientId]._destroy();
        delete Cursor._cursors[clientId];
      };
    
      peers.on("new-peer identity-updated status-updated", function (peer) {
        var c = Cursor.getClient(peer.id);
        c.updatePeer(peer);
      });
    
      var lastTime = 0;
      var MIN_TIME = 100;
      var lastPosX = -1;
      var lastPosY = -1;
      var lastMessage = null;
      function mousemove(event) {
        var now = Date.now();
        if (now - lastTime < MIN_TIME) {
          return;
        }
        lastTime = now;
        var pageX = event.pageX;
        var pageY = event.pageY;
        if (Math.abs(lastPosX - pageX) < 3 && Math.abs(lastPosY - pageY) < 3) {
  • Not a substantial enough change

          return;
        }
        lastPosX = pageX;
        lastPosY = pageY;
        var target = event.target;
        var parent = $(target).closest(".togetherjs-window, .togetherjs-popup, #togetherjs-dock");
        if (parent.length) {
          target = parent[0];
        } else if (elementFinder.ignoreElement(target)) {
          target = null;
        }
        if ((! target) || target == document.documentElement || target == document.body) {
          lastMessage = {
            type: "cursor-update",
            top: pageY,
            left: pageX
          };
          session.send(lastMessage);
          return;
        }
        target = $(target);
        var offset = target.offset();
        if (! offset) {
  • FIXME: this really is walkabout.js's problem to fire events on the document instead of a specific element

          console.warn("Could not get offset of element:", target[0]);
          return;
        }
        var offsetX = pageX - offset.left;
        var offsetY = pageY - offset.top;
        lastMessage = {
          type: "cursor-update",
          element: elementFinder.elementLocation(target),
          offsetX: Math.floor(offsetX),
          offsetY: Math.floor(offsetY)
        };
        session.send(lastMessage);
      }
    
      function makeCursor(color) {
        var canvas = $("<canvas></canvas>");
        canvas.attr("height", CURSOR_HEIGHT);
        canvas.attr("width", CURSOR_WIDTH);
        var context = canvas[0].getContext('2d');
        context.fillStyle = color;
        context.moveTo(0, 0);
        context.beginPath();
        context.lineTo(0, CURSOR_HEIGHT/1.2);
        context.lineTo(Math.sin(CURSOR_ANGLE/2) * CURSOR_HEIGHT / 1.5,
                       Math.cos(CURSOR_ANGLE/2) * CURSOR_HEIGHT / 1.5);
        context.lineTo(Math.sin(CURSOR_ANGLE) * CURSOR_HEIGHT / 1.2,
                       Math.cos(CURSOR_ANGLE) * CURSOR_HEIGHT / 1.2);
        context.lineTo(0, 0);
        context.shadowColor = 'rgba(0,0,0,0.3)';
        context.shadowBlur = 2;
        context.shadowOffsetX = 1;
        context.shadowOffsetY = 2;
    	context.strokeStyle = "#ffffff";
    	context.stroke();
        context.fill();
        return canvas[0].toDataURL("image/png");
      }
    
      var scrollTimeout = null;
      var scrollTimeoutSet = 0;
      var SCROLL_DELAY_TIMEOUT = 75;
      var SCROLL_DELAY_LIMIT = 300;
    
      function scroll() {
        var now = Date.now();
        if (scrollTimeout) {
          if (now - scrollTimeoutSet < SCROLL_DELAY_LIMIT) {
            clearTimeout(scrollTimeout);
          } else {
  • Just let it progress anyway

            return;
          }
        }
        scrollTimeout = setTimeout(_scrollRefresh, SCROLL_DELAY_TIMEOUT);
        if (! scrollTimeoutSet) {
          scrollTimeoutSet = now;
        }
      }
    
      var lastScrollMessage = null;
      function _scrollRefresh() {
        scrollTimeout = null;
        scrollTimeoutSet = 0;
        Cursor.forEach(function (c) {
          c.refresh();
        });
        lastScrollMessage = {
          type: "scroll-update",
          position: elementFinder.elementByPixel($(window).scrollTop())
        };
        session.send(lastScrollMessage);
      }
  • FIXME: do the same thing for cursor position? And give up on the ad hoc update-on-hello?

      session.on("prepare-hello", function (helloMessage) {
        if (lastScrollMessage) {
          helloMessage.scrollPosition = lastScrollMessage.position;
        }
      });
    
      session.hub.on("scroll-update", function (msg) {
        msg.peer.scrollPosition = msg.position;
        if (msg.peer.following) {
          msg.peer.view.scrollTo();
        }
      });
  • In case there are multiple peers, we track that we've accepted one of their hello-based scroll updates, just so we don't bounce around (we don't intelligently choose which one to use, just the first that comes in)

      var acceptedScrollUpdate = false;
      session.hub.on("hello-back hello", function (msg) {
        if (msg.type == "hello") {
  • Once a hello comes in, a bunch of hello-backs not intended for us will also come in, and we should ignore them

          acceptedScrollUpdate = true;
        }
        if (! msg.scrollPosition) {
          return;
        }
        msg.peer.scrollPosition = msg.scrollPosition;
        if ((! acceptedScrollUpdate) &&
            msg.sameUrl &&
            Date.now() - session.timeHelloSent < SCROLL_UPDATE_CUTOFF) {
          acceptedScrollUpdate = true;
          msg.peer.view.scrollTo();
        }
      });
    
      session.on("ui-ready", function () {
        $(document).mousemove(mousemove);
        document.addEventListener("click", documentClick, true);
        document.addEventListener("keydown", documentKeydown, true);
        $(window).scroll(scroll);
        scroll();
      });
    
      session.on("close", function () {
        Cursor.forEach(function (c, clientId) {
          Cursor.destroy(clientId);
        });
        $(document).unbind("mousemove", mousemove);
        document.removeEventListener("click", documentClick, true);
        document.removeEventListener("keydown", documentKeydown, true);
        $(window).unbind("scroll", scroll);
      });
    
      session.hub.on("hello", function (msg) {
  • Immediately get our cursor onto this new person's screen:

        if (lastMessage) {
          session.send(lastMessage);
        }
        if (lastScrollMessage) {
          session.send(lastScrollMessage);
        }
      });
    
      function documentClick(event) {
        if (event.togetherjsInternal) {
  • This is an artificial internal event

          return;
        }
  • FIXME: this might just be my imagination, but somehow I just really don't want to do anything at this stage of the event handling (since I'm catching every click), and I'll just do something real soon:

        setTimeout(function () {
          if (! TogetherJS.running) {
  • This can end up running right after TogetherJS has been closed, often because TogetherJS was closed with a click...

            return;
          }
          var element = event.target;
          if (element == document.documentElement) {
  • For some reason clicking on gives the element here

            element = document.body;
          }
          if (elementFinder.ignoreElement(element)) {
            return;
          }
  • Prevent click events on video objects to avoid conflicts with togetherjs's own video events

          if (element.nodeName.toLowerCase() === 'video'){
            return;
          }
    
          var dontShowClicks = TogetherJS.config.get("dontShowClicks");
          var cloneClicks = TogetherJS.config.get("cloneClicks");
  • If you dont want to clone the click for this element and you dont want to show the click for this element or you dont want to show any clicks then return to avoid sending a useless click

          if ((! util.matchElement(element, cloneClicks)) && util.matchElement(element, dontShowClicks)) {
            return;
          }
          var location = elementFinder.elementLocation(element);
          var offset = $(element).offset();
          var offsetX = event.pageX - offset.left;
          var offsetY = event.pageY - offset.top;
          session.send({
            type: "cursor-click",
            element: location,
            offsetX: offsetX,
            offsetY: offsetY
          });
          if (util.matchElement(element, dontShowClicks)) {
            return;
          }
          displayClick({top: event.pageY, left: event.pageX}, peers.Self.color);
        });
      }
    
      var CLICK_TRANSITION_TIME = 3000;
    
      session.hub.on("cursor-click", function (pos) {
  • When the click is calculated isn't always the same as how the last cursor update was calculated, so we force the cursor to the last location during a click:

        if (! pos.sameUrl) {
  • FIXME: if we could have done a local click, but we follow along later, we'll be in different states if that click was important. Mostly click cloning just won't work.

          return;
        }
        Cursor.getClient(pos.clientId).updatePosition(pos);
        var target = $(elementFinder.findElement(pos.element));
        var offset = target.offset();
        var top = offset.top + pos.offsetY;
        var left = offset.left + pos.offsetX;
        var cloneClicks = TogetherJS.config.get("cloneClicks");
        if (util.matchElement(target, cloneClicks)) {
          eventMaker.performClick(target);
        }
        var dontShowClicks = TogetherJS.config.get("dontShowClicks");
        if (util.matchElement(target, dontShowClicks)) {
          return;
        }
        displayClick({top: top, left: left}, pos.peer.color);
      });
    
      function displayClick(pos, color) {
  • FIXME: should we hide the local click if no one else is going to see it? That means tracking who might be able to see our screen.

        var element = templating.clone("click");
        $(document.body).append(element);
        element.css({
          top: pos.top,
          left: pos.left,
          borderColor: color
        });
        setTimeout(function () {
          element.addClass("togetherjs-clicking");
        }, 100);
        setTimeout(function () {
          element.remove();
        }, CLICK_TRANSITION_TIME);
      }
    
      var lastKeydown = 0;
      var MIN_KEYDOWN_TIME = 500;
    
      function documentKeydown(event) {
        setTimeout(function () {
          var now = Date.now();
          if (now - lastKeydown < MIN_KEYDOWN_TIME) {
            return;
          }
          lastKeydown = now;
  • FIXME: is event.target interesting here? That is, what the user is typing into, not just that the user is typing? Also I'm assuming we don't care if the user it typing into a togetherjs-related field, since chat activity is as interesting as any other activity.

          session.send({type: "keydown"});
        });
      }
    
      session.hub.on("keydown", function (msg) {
  • FIXME: when the cursor is hidden there's nothing to show with setKeydown().

        var cursor = Cursor.getClient(msg.clientId);
        cursor.setKeydown();
      });
    
      util.testExpose({Cursor: Cursor});
    
      return cursor;
    
    });