open-nomad/ui/app/components/flex-masonry.js
2022-01-20 09:54:56 -05:00

81 lines
2.7 KiB
JavaScript

import Component from '@glimmer/component';
import { tracked } from '@glimmer/tracking';
import { run } from '@ember/runloop';
import { action } from '@ember/object';
import { minIndex, max } from 'd3-array';
export default class FlexMasonry extends Component {
@tracked element = null;
@action
captureElement(element) {
this.element = element;
}
@action
reflow() {
run.next(() => {
// There's nothing to do if there is no element
if (!this.element) return;
const items = this.element.querySelectorAll(
':scope > .flex-masonry-item'
);
// Clear out specified order and flex-basis values in case this was once a multi-column layout
if (this.args.columns === 1 || !this.args.columns) {
for (let item of items) {
item.style.flexBasis = null;
item.style.order = null;
}
this.element.style.maxHeight = null;
return;
}
const columns = new Array(this.args.columns).fill(null).map(() => ({
height: 0,
elements: [],
}));
// First pass: assign each element to a column based on the running heights of each column
for (let item of items) {
const styles = window.getComputedStyle(item);
const marginTop = parseFloat(styles.marginTop);
const marginBottom = parseFloat(styles.marginBottom);
const height = item.clientHeight;
// Pick the shortest column accounting for margins
const column = columns[minIndex(columns, (c) => c.height)];
// Add the new element's height to the column height
column.height += marginTop + height + marginBottom;
column.elements.push(item);
}
// Second pass: assign an order to each element based on their column and position in the column
columns
.mapBy('elements')
.flat()
.forEach((dc, index) => {
dc.style.order = index;
});
// Guarantee column wrapping as predicted (if the first item of a column is shorter than the difference
// beteen the height of the column and the previous column, then flexbox will naturally place the first
// item at the end of the previous column).
columns.forEach((column, index) => {
const nextHeight =
index < columns.length - 1 ? columns[index + 1].height : 0;
const item = column.elements.lastObject;
if (item) {
item.style.flexBasis =
item.clientHeight + Math.max(0, nextHeight - column.height) + 'px';
}
});
// Set the max height of the container to the height of the tallest column
this.element.style.maxHeight = max(columns.mapBy('height')) + 1 + 'px';
});
}
}