lib/dojo/dnd/autoscroll.js.uncompressed.js

   1 define("dojo/dnd/autoscroll", ["../_base/lang", "../sniff", "../_base/window", "../dom-geometry", "../dom-style", "../window"],
   2         function(lang, has, win, domGeom, domStyle, winUtils){
   3
   4 // module:
   5 //              dojo/dnd/autoscroll
   6
   7 var exports = {
   8         // summary:
   9         //              Used by dojo/dnd/Manager to scroll document or internal node when the user
  10         //              drags near the edge of the viewport or a scrollable node
  11 };
  12 lang.setObject("dojo.dnd.autoscroll", exports);
  13
  14 exports.getViewport = winUtils.getBox;
  15
  16 exports.V_TRIGGER_AUTOSCROLL = 32;
  17 exports.H_TRIGGER_AUTOSCROLL = 32;
  18
  19 exports.V_AUTOSCROLL_VALUE = 16;
  20 exports.H_AUTOSCROLL_VALUE = 16;
  21
  22 // These are set by autoScrollStart().
  23 // Set to default values in case autoScrollStart() isn't called. (back-compat, remove for 2.0)
  24 var viewport,
  25         doc = win.doc,
  26         maxScrollTop = Infinity,
  27         maxScrollLeft = Infinity;
  28
  29 exports.autoScrollStart = function(d){
  30         // summary:
  31         //              Called at the start of a drag.
  32         // d: Document
  33         //              The document of the node being dragged.
  34
  35         doc = d;
  36         viewport = winUtils.getBox(doc);
  37
  38         // Save height/width of document at start of drag, before it gets distorted by a user dragging an avatar past
  39         // the document's edge
  40         var html = win.body(doc).parentNode;
  41         maxScrollTop = Math.max(html.scrollHeight - viewport.h, 0);
  42         maxScrollLeft = Math.max(html.scrollWidth - viewport.w, 0);     // usually 0
  43 };
  44
  45 exports.autoScroll = function(e){
  46         // summary:
  47         //              a handler for mousemove and touchmove events, which scrolls the window, if
  48         //              necessary
  49         // e: Event
  50         //              mousemove/touchmove event
  51
  52         // FIXME: needs more docs!
  53         var v = viewport || winUtils.getBox(doc), // getBox() call for back-compat, in case autoScrollStart() wasn't called
  54                 html = win.body(doc).parentNode,
  55                 dx = 0, dy = 0;
  56         if(e.clientX < exports.H_TRIGGER_AUTOSCROLL){
  57                 dx = -exports.H_AUTOSCROLL_VALUE;
  58         }else if(e.clientX > v.w - exports.H_TRIGGER_AUTOSCROLL){
  59                 dx = Math.min(exports.H_AUTOSCROLL_VALUE, maxScrollLeft - html.scrollLeft);     // don't scroll past edge of doc
  60         }
  61         if(e.clientY < exports.V_TRIGGER_AUTOSCROLL){
  62                 dy = -exports.V_AUTOSCROLL_VALUE;
  63         }else if(e.clientY > v.h - exports.V_TRIGGER_AUTOSCROLL){
  64                 dy = Math.min(exports.V_AUTOSCROLL_VALUE, maxScrollTop - html.scrollTop);       // don't scroll past edge of doc
  65         }
  66         window.scrollBy(dx, dy);
  67 };
  68
  69 exports._validNodes = {"div": 1, "p": 1, "td": 1};
  70 exports._validOverflow = {"auto": 1, "scroll": 1};
  71
  72 exports.autoScrollNodes = function(e){
  73         // summary:
  74         //              a handler for mousemove and touchmove events, which scrolls the first available
  75         //              Dom element, it falls back to exports.autoScroll()
  76         // e: Event
  77         //              mousemove/touchmove event
  78
  79         // FIXME: needs more docs!
  80
  81         var b, t, w, h, rx, ry, dx = 0, dy = 0, oldLeft, oldTop;
  82
  83         for(var n = e.target; n;){
  84                 if(n.nodeType == 1 && (n.tagName.toLowerCase() in exports._validNodes)){
  85                         var s = domStyle.getComputedStyle(n),
  86                                 overflow = (s.overflow.toLowerCase() in exports._validOverflow),
  87                                 overflowX = (s.overflowX.toLowerCase() in exports._validOverflow),
  88                                 overflowY = (s.overflowY.toLowerCase() in exports._validOverflow);
  89                         if(overflow || overflowX || overflowY){
  90                                 b = domGeom.getContentBox(n, s);
  91                                 t = domGeom.position(n, true);
  92                         }
  93                         // overflow-x
  94                         if(overflow || overflowX){
  95                                 w = Math.min(exports.H_TRIGGER_AUTOSCROLL, b.w / 2);
  96                                 rx = e.pageX - t.x;
  97                                 if(has("webkit") || has("opera")){
  98                                         // FIXME: this code should not be here, it should be taken into account
  99                                         // either by the event fixing code, or the domGeom.position()
 100                                         // FIXME: this code doesn't work on Opera 9.5 Beta
 101                                         rx += win.body().scrollLeft;
 102                                 }
 103                                 dx = 0;
 104                                 if(rx > 0 && rx < b.w){
 105                                         if(rx < w){
 106                                                 dx = -w;
 107                                         }else if(rx > b.w - w){
 108                                                 dx = w;
 109                                         }
 110                                         oldLeft = n.scrollLeft;
 111                                         n.scrollLeft = n.scrollLeft + dx;
 112                                 }
 113                         }
 114                         // overflow-y
 115                         if(overflow || overflowY){
 116                                 //console.log(b.l, b.t, t.x, t.y, n.scrollLeft, n.scrollTop);
 117                                 h = Math.min(exports.V_TRIGGER_AUTOSCROLL, b.h / 2);
 118                                 ry = e.pageY - t.y;
 119                                 if(has("webkit") || has("opera")){
 120                                         // FIXME: this code should not be here, it should be taken into account
 121                                         // either by the event fixing code, or the domGeom.position()
 122                                         // FIXME: this code doesn't work on Opera 9.5 Beta
 123                                         ry += win.body().scrollTop;
 124                                 }
 125                                 dy = 0;
 126                                 if(ry > 0 && ry < b.h){
 127                                         if(ry < h){
 128                                                 dy = -h;
 129                                         }else if(ry > b.h - h){
 130                                                 dy = h;
 131                                         }
 132                                         oldTop = n.scrollTop;
 133                                         n.scrollTop  = n.scrollTop  + dy;
 134                                 }
 135                         }
 136                         if(dx || dy){ return; }
 137                 }
 138                 try{
 139                         n = n.parentNode;
 140                 }catch(x){
 141                         n = null;
 142                 }
 143         }
 144         exports.autoScroll(e);
 145 };
 146
 147 return exports;
 148
 149 });