1 | /*
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2 | * Copyright (C) 1998-2021 by Northwoods Software Corporation. All Rights Reserved.
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3 | */
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4 |
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5 | /*
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6 | * This is an extension and not part of the main GoJS library.
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7 | * Note that the API for this class may change with any version, even point releases.
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8 | * If you intend to use an extension in production, you should copy the code to your own source directory.
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9 | * Extensions can be found in the GoJS kit under the extensions or extensionsTS folders.
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10 | * See the Extensions intro page (https://gojs.net/latest/intro/extensions.html) for more information.
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11 | */
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12 |
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13 | import * as go from '../release/go-module.js';
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14 |
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15 | /**
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16 | * The NodeLabelDraggingTool class lets the user move a label on a Node.
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17 | *
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18 | * This tool only works when the Node has a label (any GraphObject) marked with
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19 | * { _isNodeLabel: true } that is positioned in a Spot Panel.
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20 | * It works by modifying that label's {@link GraphObject#alignment} property to have an
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21 | * offset from the center of the panel.
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22 | *
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23 | * If you want to experiment with this extension, try the <a href="../../extensionsJSM/NodeLabelDragging.html">Node Label Dragging</a> sample.
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24 | * @category Tool Extension
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25 | */
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26 | export class NodeLabelDraggingTool extends go.Tool {
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27 | /**
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28 | * The label being dragged.
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29 | */
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30 | public label: go.GraphObject | null = null;
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31 | private _offset: go.Point = new go.Point(); // of the mouse relative to the center of the label object
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32 | private _originalAlignment: go.Spot = go.Spot.Default;
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33 | private _originalCenter: go.Point = new go.Point();
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34 |
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35 | /**
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36 | * Constructs a NodeLabelDraggingTool and sets the name for the tool.
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37 | */
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38 | constructor() {
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39 | super();
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40 | this.name = 'NodeLabelDragging';
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41 | }
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42 |
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43 | /**
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44 | * From the GraphObject at the mouse point, search up the visual tree until we get to
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45 | * an object that has the "_isNodeLabel" property set to true, that is in a Spot Panel,
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46 | * and that is not the first element of that Panel (i.e. not the main element of the panel).
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47 | * @return {GraphObject} This returns null if no such label is at the mouse down point.
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48 | */
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49 | public findLabel(): go.GraphObject | null {
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50 | const diagram = this.diagram;
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51 | const e = diagram.firstInput;
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52 | let elt = diagram.findObjectAt(e.documentPoint, null, null);
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53 |
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54 | if (elt === null || !(elt.part instanceof go.Node)) return null;
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55 | while (elt.panel !== null) {
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56 | if ((elt as any)['_isNodeLabel'] && elt.panel.type === go.Panel.Spot && elt.panel.findMainElement() !== elt) return elt;
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57 | elt = elt.panel;
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58 | }
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59 | return null;
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60 | }
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61 |
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62 | /**
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63 | * This tool can only start if the mouse has moved enough so that it is not a click,
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64 | * and if the mouse down point is on a GraphObject "label" in a Spot Panel,
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65 | * as determined by findLabel().
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66 | */
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67 | public canStart(): boolean {
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68 | if (!super.canStart()) return false;
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69 | const diagram = this.diagram;
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70 | // require left button & that it has moved far enough away from the mouse down point, so it isn't a click
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71 | const e = diagram.lastInput;
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72 | if (!e.left) return false;
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73 | if (!this.isBeyondDragSize()) return false;
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74 |
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75 | return this.findLabel() !== null;
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76 | }
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77 |
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78 | /**
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79 | * Start a transaction, call {@link findLabel} and remember it as the "label" property,
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80 | * and remember the original value for the label's {@link GraphObject#alignment} property.
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81 | */
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82 | public doActivate(): void {
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83 | this.startTransaction('Shifted Label');
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84 | this.label = this.findLabel();
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85 | if (this.label !== null) {
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86 | // compute the offset of the mouse-down point relative to the center of the label
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87 | this._offset = this.diagram.firstInput.documentPoint.copy().subtract(this.label.getDocumentPoint(go.Spot.Center));
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88 | this._originalAlignment = this.label.alignment.copy();
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89 | const panel = this.label.panel;
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90 | if (panel !== null) {
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91 | const main = panel.findMainElement();
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92 | if (main !== null) this._originalCenter = main.getDocumentPoint(go.Spot.Center);
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93 | }
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94 | }
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95 | super.doActivate();
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96 | }
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97 |
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98 | /**
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99 | * Stop any ongoing transaction.
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100 | */
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101 | public doDeactivate(): void {
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102 | super.doDeactivate();
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103 | this.stopTransaction();
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104 | }
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105 |
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106 | /**
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107 | * Clear any reference to a label element.
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108 | */
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109 | public doStop(): void {
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110 | this.label = null;
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111 | super.doStop();
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112 | }
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113 |
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114 | /**
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115 | * Restore the label's original value for GraphObject.alignment.
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116 | */
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117 | public doCancel(): void {
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118 | if (this.label !== null) {
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119 | this.label.alignment = this._originalAlignment;
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120 | }
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121 | super.doCancel();
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122 | }
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123 |
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124 | /**
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125 | * During the drag, call updateAlignment in order to set the {@link GraphObject#alignment} of the label.
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126 | */
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127 | public doMouseMove(): void {
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128 | if (!this.isActive) return;
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129 | this.updateAlignment();
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130 | }
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131 |
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132 | /**
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133 | * At the end of the drag, update the alignment of the label and finish the tool,
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134 | * completing a transaction.
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135 | */
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136 | public doMouseUp(): void {
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137 | if (!this.isActive) return;
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138 | this.updateAlignment();
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139 | this.transactionResult = 'Shifted Label';
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140 | this.stopTool();
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141 | }
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142 |
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143 | /**
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144 | * Save the label's {@link GraphObject#alignment} as an absolute offset from the center of the Spot Panel
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145 | * that the label is in.
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146 | */
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147 | public updateAlignment(): void {
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148 | if (this.label === null) return;
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149 | const last = this.diagram.lastInput.documentPoint;
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150 | const cntr = this._originalCenter;
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151 | this.label.alignment = new go.Spot(0.5, 0.5, last.x - this._offset.x - cntr.x, last.y - this._offset.y - cntr.y);
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152 | }
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153 | }
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