Select Box
This sample demonstrates how you can implement multi-point selection on a FlexChart control. Dragging on the chart will clear the currently selected points and select a new set of points that lie within the drag area. clicking on a point will also toggle its selection state, while clicking on an empty portion of the chart will clear the current selection.
app.js
index.html
data.js
styles.css
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import 'bootstrap.css';
import '@mescius/wijmo.styles/wijmo.css';
import './styles.css';
//
import * as wjChart from '@mescius/wijmo.chart';
import * as wijmo from '@mescius/wijmo';
import { getData } from './data';
//
document.readyState === 'complete' ? init() : window.onload = init;
//
function init() {
let rendered = false, wjSelected = 'wj-state-selected', selections = [], mouseDown = false, start = null, end = null, selector = null, offset = null, mousePt = null, isTouch = false, items = [];
//
// create the chart
let chart = new wjChart.FlexChart('#theChart', {
chartType: 'Scatter',
axisY: {
axisLine: true
},
legend: {
position: 'None'
},
series: [
{
name: 'Experiment 1',
itemsSource: getData(50, 0, 3),
bindingX: 'x',
binding: 'y'
},
{
name: 'Experiment 2',
itemsSource: getData(40, 100, 12),
bindingX: 'x',
binding: 'y'
},
{
name: 'Experiment 3',
itemsSource: getData(30, -100, 24),
bindingX: 'x',
binding: 'y'
}
],
rendered: (sender) => {
if (!rendered) {
sender.hostElement.addEventListener('mousedown', chartMouseDown);
sender.hostElement.addEventListener('mousemove', chartMouseMove);
sender.hostElement.addEventListener('mouseup', chartMouseUp);
sender.hostElement.addEventListener('mouseleave', chartMouseLeave);
sender.hostElement.addEventListener('click', chartClick);
window.addEventListener('touchstart', () => isTouch = true, false);
//
// boolean flag - don't re-add event listener after resize
rendered = true;
//
selector = document.querySelector('#plotSelection');
sender.hostElement.appendChild(selector);
}
else {
// *visually* restore selection after redraw (ex. resize browser, change chart type)
restoreSelection();
}
}
});
//
// helper for clearing chart selection
function clearSelection() {
selections.forEach(item => {
let series = item.series, el = series.getPlotElement(item.pointIndex);
//
if (el) {
wijmo.removeClass(el, wjSelected);
}
});
//
selections.length = 0;
}
//
// helper for adding chart selection
function addSelection(obj) {
wijmo.addClass(obj.series.getPlotElement(obj.pointIndex), wjSelected);
//
selections.push({
series: obj.series,
pointIndex: obj.pointIndex
});
}
//
// helper for removing chart selection
function removeSelection(ht) {
let items = selections.filter(item => item.series === ht.series && item.pointIndex === ht.pointIndex), idx = items && items.length > 0 ? selections.indexOf(items[0]) : -1;
//
if (idx >= 0) {
selections.splice(idx, 1);
wijmo.removeClass(ht.series.getPlotElement(ht.pointIndex), wjSelected);
}
}
//
// finds selected plot elements after rendering and applies CSS to
// visually represent selection
function restoreSelection() {
selections.forEach(item => {
let series = item.series, el = series.getPlotElement(item.pointIndex);
//
if (el) {
wijmo.addClass(el, wjSelected);
}
});
}
//
// helper to hide the selector
function hideSelector() {
wijmo.setCss(selector, {
'visibility': 'hidden',
'width': 0,
'height': 0,
'left': 0,
'top': 0
});
}
//
// selects plot elements within drawn rectangle
function selectWithinRect(rect) {
if (!rect || !chart) {
return;
}
//
chart.series.forEach((item) => {
let pointCount = item._getLength();
//
for (let j = 0; j < pointCount; j++) {
let el = item.getPlotElement(j);
//
if (elementInBounds(el, rect)) {
addSelection({
series: item,
pointIndex: j
});
}
}
});
}
//
// helper to determine if plot element is within the bounds
// of the drawn rectangle
function elementInBounds(el, rect) {
let box = el.getBoundingClientRect();
return !(box.left > rect.right || box.right < rect.left || box.top > rect.bottom || box.bottom < rect.top);
}
//
// clear selection for button click
function clear() {
clearSelection();
// update length for view
items.length = 0;
}
//
function chartClick(e) {
if (mouseDown && !isTouch) {
isTouch = false;
return;
}
//
let p = wijmo.mouseToPage(e);
if (mousePt.x !== p.x || mousePt.y !== p.y) {
return;
}
//
let element = e.target, ht = chart.hitTest(e), selected = false, chartType = chart.chartType;
//
selected = selections.some(function (item) {
return item.series === ht.series && item.pointIndex === ht.pointIndex;
});
//
if (ht && ht.series && !selected && ((ht.distance <= 0 && (chartType == 0 || chartType == 1)) || ht.distance <= 15) && isTouch) {
// remove selection
if (wijmo.hasClass(element, wjSelected)) {
removeSelection(ht);
}
// add selection
else {
addSelection(ht);
}
}
else if (selected && ((ht.distance <= 0 && (chartType == 0 || chartType == 1)) || ht.distance <= 15) && isTouch) {
removeSelection(ht);
}
else {
clearSelection();
}
//
isTouch = false;
// update length for view
items.length = 0;
items.push.apply(items, selections);
}
//
function chartMouseDown(e) {
mousePt = wijmo.mouseToPage(e);
mouseDown = true;
e.preventDefault();
}
//
function chartMouseUp(e) {
if (start != null) {
start = null;
}
//
if (end != null) {
let host = chart.hostElement;
offset = wijmo.getElementRect(host);
//
let style = host.getAttribute('style');
offset.left = offset.left + parseInt(style ? style['padding-left'].replace('px', '') : 0);
offset.top = offset.top + parseInt(style ? style['padding-top'].replace('px', '') : 0);
//
end = start = null;
//
clear();
selectWithinRect(selector.getBoundingClientRect());
//
// update length for view
items.length = 0;
items.push.apply(items, selections);
//
e.preventDefault();
}
//
hideSelector();
mouseDown = false;
}
//
function chartMouseMove(e) {
let p = wijmo.mouseToPage(e);
if (!mouseDown || (mousePt.x == p.x && mousePt.y == p.y)) {
return;
}
//
let pt = e instanceof MouseEvent ? new wijmo.Point(e.pageX, e.pageY) : new wijmo.Point(e.changedTouches[0].pageX, e.changedTouches[0].pageY);
//
if (start != null) {
end = pt;
//
// update selector rectangle
let w = pt.x - start.x, h = pt.y - start.y;
//
if (w >= 0) {
wijmo.setCss(selector, {
'left': start.x - offset.left,
'width': w
});
}
else {
wijmo.setCss(selector, {
'left': pt.x - offset.left,
'width': -w
});
}
//
if (h >= 0) {
wijmo.setCss(selector, {
'top': start.y - offset.top,
'height': h
});
}
else {
wijmo.setCss(selector, {
'top': pt.y - offset.top,
'height': -h
});
}
}
else {
wijmo.setCss(selector, {
'visibility': 'visible'
});
offset = wijmo.getElementRect(selector);
//
start = pt;
}
//
e.preventDefault();
}
//
function chartMouseLeave(e) {
if (start) {
start = end = null;
mouseDown = false;
hideSelector();
}
}
}
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