control-freak-ide/misc/pocs/GoJS/extensions/ScrollingTable.js

"use strict";
/*
*  Copyright (C) 1998-2017 by Northwoods Software Corporation. All Rights Reserved.
*/

// A "ScrollingTable" Panel

// This also defines an "AutoRepeatButton" Panel,
// which is used by the scrollbar in the "ScrollingTable" Panel.

// This defines a custom "Button" that automatically repeats its click
// action when the user holds down the mouse.
go.GraphObject.defineBuilder("AutoRepeatButton", function(args) {
  var $ = go.GraphObject.make;
  // some internal helper functions for auto-repeating
  function delayClicking(e, obj) {
    endClicking(e, obj);
    if (obj.click) {
      obj._timer =
        setTimeout(function() { repeatClicking(e, obj); },
                   500);  // wait 0.5 seconds before starting clicks
    }
  }
  function repeatClicking(e, obj) {
    if (obj._timer) clearTimeout(obj._timer);
    if (obj.click) {
      obj._timer =
        setTimeout(function() {
                     if (obj.click) {
                       (obj.click)(e, obj);
                       repeatClicking(e, obj);
                     }
                   },
                   100);  // 0.1 seconds between clicks
    }
  }
  function endClicking(e, obj) {
    if (obj._timer) {
      clearTimeout(obj._timer);
      obj._timer = undefined;
    }
  }

  return $("Button",
           { actionDown: delayClicking, actionUp: endClicking });
});

// Create a scrolling Table Panel, whose name is given as the optional first argument.
// If not given the name defaults to "TABLE".
// Example use:
//   $("ScrollingTable", "TABLE",
//     new go.Binding("TABLE.itemArray", "someArrayProperty"),
//     ...)
// Note that if you have more than one of these in a Part,
// you'll want to make sure each one has a unique name.
go.GraphObject.defineBuilder("ScrollingTable", function(args) {
  var $ = go.GraphObject.make;
  var tablename = go.GraphObject.takeBuilderArgument(args, "TABLE");

  // an internal helper function for actually performing a scrolling operation
  function incrTableIndex(obj, i) {
    var diagram = obj.diagram;
    var table = obj.panel.panel.panel.findObject(tablename);
    if (i === +Infinity || i === -Infinity) {  // page up or down
      var tabh = table.actualBounds.height;
      var rowh = table.elt(table.topIndex).actualBounds.height;  // assume each row has same height?
      if (i === +Infinity) {
        i = Math.max(1, Math.ceil(tabh / rowh) - 1);
      } else {
        i = -Math.max(1, Math.ceil(tabh / rowh) - 1);
      }
    }
    var idx = table.topIndex + i;
    if (idx < 0) idx = 0;
    else if (idx >= table.rowCount - 1) idx = table.rowCount - 1;
    if (table.topIndex !== idx) {
      if (diagram !== null) diagram.startTransaction("scroll");
      table.topIndex = idx;
      var node = table.part;  // may need to reroute links if the table contains any ports
      if (node instanceof go.Node) node.invalidateConnectedLinks();
      updateScrollBar(table);
      if (diagram !== null) diagram.commitTransaction("scroll");
    }
  }

  function updateScrollBar(table) {
    var bar = table.panel.elt(1);  // the scrollbar is a sibling of the table
    if (!bar) return;
    var idx = table.topIndex;

    var up = bar.findObject("UP");
    if (up) up.opacity = (idx > 0) ? 1.0 : 0.3;

    var down = bar.findObject("DOWN");
    if (down) down.opacity = (idx < table.rowCount - 1) ? 1.0 : 0.3;

    var tabh = bar.actualBounds.height;
    var rowh = table.elt(idx).actualBounds.height;  //?? assume each row has same height?
    if (rowh === 0 && idx < table.rowCount-2) rowh = table.elt(idx + 1).actualBounds.height;
    var numVisibleRows = Math.max(1, Math.ceil(tabh / rowh) - 1);
    var needed = idx > 0 || idx + numVisibleRows <= table.rowCount;
    bar.opacity = needed ? 1.0 : 0.0;
  }

  return $(go.Panel, "Table",
      {
        _updateScrollBar: updateScrollBar
      },
      // this actually holds the item elements
      $(go.Panel, "Table",
        {
          name: tablename,
          column: 0,
          stretch: go.GraphObject.Fill,
          background: "whitesmoke",
          rowSizing: go.RowColumnDefinition.None,
          defaultAlignment: go.Spot.Top
        }),

      // this is the scrollbar
      $(go.RowColumnDefinition,
        { column: 1, sizing: go.RowColumnDefinition.None }),
      $(go.Panel, "Table",
        { column: 1, stretch: go.GraphObject.Vertical, background: "#DDDDDD" },
        // the scroll up button
        $("AutoRepeatButton",
          {
            name: "UP",
            row: 0,
            alignment: go.Spot.Top,
            "ButtonBorder.figure": "Rectangle",
            "ButtonBorder.fill": "lightgray",
            click: function(e, obj) { incrTableIndex(obj, -1); }
          },
          $(go.Shape, "TriangleUp",
            { stroke: null, desiredSize: new go.Size(6, 6) })),
        // (someday implement a thumb here and support dragging to scroll)
        // the scroll down button
        $("AutoRepeatButton",
          {
            name: "DOWN",
            row: 2,
            alignment: go.Spot.Bottom,
            "ButtonBorder.figure": "Rectangle",
            "ButtonBorder.fill": "lightgray",
            click: function(e, obj) { incrTableIndex(obj, +1); }
          },
          $(go.Shape, "TriangleDown",
            { stroke: null, desiredSize: new go.Size(6, 6) }))
      )
    );
});