# all files / diagram-js/lib/features/snapping/ Snapping.js

100% Statements 52/52
95.45% Branches 21/22
100% Functions 12/12
100% Lines 52/52

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74
    75
    76
    77
    78
    79
    80
    81
    82
    83
    84
    85
    86
    87
    88
    89
    90
    91
    92
    93
    94
    95
    96
    97
    98
    99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157
    158
    159
    160
    161
    162
    163
    164
    165

    1×

    1×

    93×

    93×

    1×

    1×
    55×
    55×
    55×

    55×

    55×
    95×

    95×

    95×

    190×
    162×

    162×
    53×

    95×
    23×

    55×
    55×

    55×
    110×

    110×
    53×

    1×
    56×

    56×

    56×

    56×

    56×

    56×

    222×
    169×

    53×
    23×

    30×

    1×
    28×

    1×

    110×

    110×
    110×

    110×

    1×
    110×
    28×

    110×

    1×
    58×
    112×

     import {
      bind,
      debounce,
      forEach,
      isNumber,
      isObject
    } from 'min-dash';

    import {
      isSnapped,
      setSnapped
    } from './SnapUtil';

    import {
      append as svgAppend,
      attr as svgAttr,
      classes as svgClasses,
      create as svgCreate
    } from 'tiny-svg';

    var SNAP_TOLERANCE = 7;

    export var SNAP_LINE_HIDE_DELAY = 1000;

    /**
     * Generic snapping feature.
     *
     * @param {EventBus} eventBus
     * @param {Canvas} canvas
     */
    export default function Snapping(canvas) {
      this._canvas = canvas;

      // delay hide by 1000 seconds since last snap
      this._asyncHide = debounce(bind(this.hide, this), SNAP_LINE_HIDE_DELAY);
    }

    Snapping.$inject = [ 'canvas' ];

    /**
     * Snap an event to given snap points.
     *
     * @param {Event} event
     * @param {SnapPoints} snapPoints
     */
    Snapping.prototype.snap = function(event, snapPoints) {
      var context = event.context,
          snapContext = context.snapContext,
          snapLocations = snapContext.getSnapLocations();

      var snapping = {
        x: isSnapped(event, 'x'),
        y: isSnapped(event, 'y')
      };

      forEach(snapLocations, function(location) {
        var snapOrigin = snapContext.getSnapOrigin(location);

        var snapCurrent = {
          x: event.x + snapOrigin.x,
          y: event.y + snapOrigin.y
        };

        // snap both axis if not snapped already
        forEach([ 'x', 'y' ], function(axis) {
          var locationSnapping;

          if (!snapping[axis]) {
            locationSnapping = snapPoints.snap(snapCurrent, location, axis, SNAP_TOLERANCE);

            if (locationSnapping !== undefined) {
              snapping[axis] = {
                value: locationSnapping,
                originValue: locationSnapping - snapOrigin[axis]
              };
            }
          }
        });

        // no need to continue snapping
        if (snapping.x && snapping.y) {
          return false;
        }
      });

      // show snap lines
      this.showSnapLine('vertical', snapping.x && snapping.x.value);
      this.showSnapLine('horizontal', snapping.y && snapping.y.value);

      // snap event
      forEach([ 'x', 'y' ], function(axis) {
        var axisSnapping = snapping[axis];

        if (isObject(axisSnapping)) {
          setSnapped(event, axis, axisSnapping.originValue);
        }
      });
    };

    Snapping.prototype._createLine = function(orientation) {
      var root = this._canvas.getLayer('snap');

      var line = svgCreate('path');

      svgAttr(line, { d: 'M0,0 L0,0' });

      svgClasses(line).add('djs-snap-line');

      svgAppend(root, line);

      return {
        update: function(position) {

          if (!isNumber(position)) {
            svgAttr(line, { display: 'none' });
          } else {
            if (orientation === 'horizontal') {
              svgAttr(line, {
                d: 'M-100000,' + position + ' L+100000,' + position,
                display: ''
              });
            } else {
              svgAttr(line, {
                d: 'M ' + position + ',-100000 L ' + position + ', +100000',
                display: ''
              });
            }
          }
        }
      };
    };

    Snapping.prototype._createSnapLines = function() {
      this._snapLines = {
        horizontal: this._createLine('horizontal'),
        vertical: this._createLine('vertical')
      };
    };

    Snapping.prototype.showSnapLine = function(orientation, position) {

      var line = this.getSnapLine(orientation);

      Eif (line) {
        line.update(position);
      }

      this._asyncHide();
    };

    Snapping.prototype.getSnapLine = function(orientation) {
      if (!this._snapLines) {
        this._createSnapLines();
      }

      return this._snapLines[orientation];
    };

    Snapping.prototype.hide = function() {
      forEach(this._snapLines, function(snapLine) {
        snapLine.update();
      });
    };