autoscroll.js

   1 /* MIT/X Consortium License
   2  *
   3  * Copyright (c) 2011-2012 Stefan Bolte <portix@gmx.net>
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be included in
  13  * all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 MouseAutoScroll = (function() {
  25   const SCROLL_ICON="transparent url(data:image/png;base64,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) no-repeat scroll center";
  26   const SIZE = 32;
  27   const OFFSET = 5;
  28   var doc;
  29   Math.sign = function(x) { return x >=0 ? 1  : -1; };
  30   var span = null;
  31   var x = 0;
  32   var y = 0;
  33   var ev = null;
  34   var timerId = 0;
  35   var cursorStyle = null;
  36   function startTimer() {
  37     timerId = window.setInterval(timer, 40);
  38   }
  39   function stopTimer () {
  40     window.clearInterval(timerId);
  41     timerId = 0;
  42   }
  43   function timer () {
  44     if (ev) {
  45       var scrollY = (ev.y - y);
  46       var scrollX = (ev.x - x);
  47       var b = scrollY > 0
  48         && doc.documentElement.scrollHeight == (window.innerHeight + window.pageYOffset);
  49       var r = scrollX > 0
  50         && doc.documentElement.scrollWidth == (window.innerWidth + window.pageXOffset);
  51       var l = scrollX < 0 && window.pageXOffset == 0;
  52       var t = scrollY < 0 && window.pageYOffset == 0;
  53       var offX = Math.abs(scrollX) < OFFSET;
  54       var offY = Math.abs(scrollY) < OFFSET;
  55       if ( timerId != 0
  56           && (( b && r ) || ( b && l) || ( b && offX )
  57             || ( t && r ) || ( t && l) || ( t && offX )
  58             || (offY && r) || (offY && l) )) {
  59               stopTimer();
  60               return;
  61             }
  62       window.scrollBy(scrollX - Math.sign(scrollX) * OFFSET,
  63           scrollY - Math.sign(scrollY) * OFFSET);
  64     }
  65   }
  66   function mouseMove (e) {
  67     if (timerId == 0) {
  68       startTimer();
  69     }
  70     ev = e;
  71   }
  72   function init (e) {
  73     doc = e.target.ownerDocument;
  74     if (window.innerHeight >= doc.documentElement.scrollHeight
  75         && window.innerWidth >= doc.documentElement.scrollWidth) {
  76           return;
  77         }
  78     span = doc.createElement("div");
  79     span.style.width = SIZE + "px";
  80     span.style.height = SIZE + "px";
  81     span.style.background = SCROLL_ICON;
  82     span.style.left = e.x - (SIZE / 2) + "px";
  83     span.style.top  = e.y - (SIZE / 2) + "px";
  84     span.style.position = "fixed";
  85     span.style.fontSize = SIZE + "px";
  86     span.style.opacity = 0.6;
  87     cursorStyle = doc.defaultView.getComputedStyle(doc.body, null).cursor;
  88     doc.body.style.cursor = "move";
  89     doc.body.appendChild(span);
  90     doc.addEventListener('mousemove', mouseMove, false);
  91     span = span;
  92   }
  93   function clear (e) {
  94     doc.body.style.cursor = cursorStyle;
  95     span.parentNode.removeChild(span);
  96     doc.removeEventListener('mousemove', mouseMove, false);
  97     stopTimer();
  98     if (span)
  99       span =  null;
 100     if (ev)
 101       ev = null;
 102   }
 103   function mouseUp (e) { /* Simulate click, click event does not work during scrolling */
 104     if (Math.abs(e.x - x) < 5 && Math.abs(e.y - y) < 5) {
 105       init(e);
 106       window.removeEventListener('mouseup', mouseUp, false);
 107     }
 108   }
 109   function mouseDown (e) {
 110     var t = e.target;
 111     if (e.button == 0) {
 112       if (span) {
 113         clear();
 114       }
 115     } else if (e.button == 1) {
 116       if (span) {
 117         clear();
 118       }
 119       else if (!t.hasAttribute("href")
 120           && !t.hasAttribute("onmousedown")
 121           && !(t.hasAttribute("onclick"))) {
 122         x = e.x;
 123         y = e.y;
 124         window.addEventListener('mouseup', mouseUp, false);
 125       }
 126     }
 127   }
 128   window.addEventListener('mousedown', mouseDown, false);
 129 })();