vis.js is a dynamic, browser-based visualization library
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// Utility functions for ordering and stacking of items
var EPSILON = 0.001; // used when checking collisions, to prevent round-off errors
/**
* Order items by their start data
* @param {Item[]} items
*/
exports.orderByStart = function(items) {
items.sort(function (a, b) {
return a.data.start - b.data.start;
});
};
/**
* Order items by their end date. If they have no end date, their start date
* is used.
* @param {Item[]} items
*/
exports.orderByEnd = function(items) {
items.sort(function (a, b) {
var aTime = ('end' in a.data) ? a.data.end : a.data.start,
bTime = ('end' in b.data) ? b.data.end : b.data.start;
return aTime - bTime;
});
};
/**
* Adjust vertical positions of the items such that they don't overlap each
* other.
* @param {Item[]} items
* All visible items
* @param {{item: {horizontal: number, vertical: number}, axis: number}} margin
* Margins between items and between items and the axis.
* @param {boolean} [force=false]
* If true, all items will be repositioned. If false (default), only
* items having a top===null will be re-stacked
*/
exports.stack = function(items, margin, force) {
var i, iMax;
if (force) {
// reset top position of all items
for (i = 0, iMax = items.length; i < iMax; i++) {
items[i].top = null;
}
}
// calculate new, non-overlapping positions
for (i = 0, iMax = items.length; i < iMax; i++) {
var item = items[i];
if (item.top === null) {
// initialize top position
item.top = margin.axis;
do {
// TODO: optimize checking for overlap. when there is a gap without items,
// you only need to check for items from the next item on, not from zero
var collidingItem = null;
for (var j = 0, jj = items.length; j < jj; j++) {
var other = items[j];
if (other.top !== null && other !== item && other.ignoreStacking == false && exports.collision(item, other, margin.item)) {
collidingItem = other;
break;
}
}
if (collidingItem != null) {
// There is a collision. Reposition the items above the colliding element
item.top = collidingItem.top + collidingItem.height + margin.item.vertical;
}
} while (collidingItem);
}
}
};
/**
* Adjust vertical positions of the items without stacking them
* @param {Item[]} items
* All visible items
* @param {{item: {horizontal: number, vertical: number}, axis: number}} margin
* Margins between items and between items and the axis.
*/
exports.nostack = function(items, margin, subgroups) {
var i, iMax;
// reset top position of all items
for (i = 0, iMax = items.length; i < iMax; i++) {
if (items[i].data.subgroup !== undefined) {
items[i].top = margin.axis + (subgroups[items[i].data.subgroup].height + margin.item.vertical) * items[i].data.subgroup;
}
else {
items[i].top = margin.axis;
}
}
};
/**
* Test if the two provided items collide
* The items must have parameters left, width, top, and height.
* @param {Item} a The first item
* @param {Item} b The second item
* @param {{horizontal: number, vertical: number}} margin
* An object containing a horizontal and vertical
* minimum required margin.
* @return {boolean} true if a and b collide, else false
*/
exports.collision = function(a, b, margin) {
return ((a.left - margin.horizontal + EPSILON) < (b.left + b.width) &&
(a.left + a.width + margin.horizontal - EPSILON) > b.left &&
(a.top - margin.vertical + EPSILON) < (b.top + b.height) &&
(a.top + a.height + margin.vertical - EPSILON) > b.top);
};