interpolated-charts/README.md

Configurable d3 v4 charts with interpolation and missing data range

# Interpolated Charts

Configurable [d3 v4](https://github.com/d3/d3) charts with interpolation and missing data range. Inspired by [Britecharts](https://github.com/eventbrite/britecharts)

Angular component [here](https://github.com/z3ut/ng-interpolated-charts)

[![npm version](https://badge.fury.io/js/interpolated-charts.svg)](https://badge.fury.io/js/interpolated-charts)

[Live demo](https://z3ut.github.io/interpolated-charts)

![default-interpolated-chart](https://raw.githubusercontent.com/z3ut/interpolated-charts/master/img/default-interpolated-chart.gif)

## Description

- Configurable line chart with tooltip and markers
- Gasps between data points (missing data range)
- Compute and display interpolated values between data points

Iterpolation values are calculated on svg path element using the binary search method. It means that after changing chart curve type (d3.curveBasis, d3.curveCatmullRom, ...) computed values can change. Do not rely on this data if you need high accuracy.

## Installation

1. Install with [npm](https://www.npmjs.com)

```
npm install interpolated-charts --save
```

2. Import JS dependencies

```javascript
import * as d3 from 'd3';
import { line, stackBar, chartEvents, verticalDivider, markers, tooltip } from 'interpolated-charts';
```

3. Import CSS

```
@import 'interpolated-charts/src/index.css'
```

## Usage

Package include line chart and three plugins: vertical divider, markers highlight, tooltip information. Line chart dispatch mouse events (chartMouseEnter, chartMouseLeave, chartMouseMove, chartMouseClick), defined in chartEvents. Default configuration for chart with plugins:

```javascript
const verticalDividerPlugin = verticalDivider();
const markersPlugin = markers();
const tooltipPlugin = tooltip();

const lineChart = line()
  // subscribe plugins to chart events
  .on(chartEvents.chartMouseEnter, () => {
    verticalDividerPlugin.show();
  })
  .on(chartEvents.chartMouseLeave, () => {
    verticalDividerPlugin.remove();
    markersPlugin.remove();
    tooltipPlugin.remove();
  })
  .on(chartEvents.chartMouseMove, (options) => {
    verticalDividerPlugin.update(options);
    markersPlugin.show(options);
    tooltipPlugin.show(options);
  });

// create chart with data
const chartContainer = d3.select('.default-chart');
chartContainer.datum(lineChartData).call(lineChart);

// bind plugins to chart
const metadataContainer = d3.select('.default-chart .metadata-container');
metadataContainer.datum([]).call(verticalDividerPlugin);
metadataContainer.datum([]).call(markersPlugin);
metadataContainer.datum([]).call(tooltipPlugin);
```

Chart data example:

```javascript
const lineChartData = [
  // each object represent chart line dataset
  {
    'name': 'Minsk',
    // optional color
    'color': 'darkblue',
    'data': [
      { 'date': new Date('2015-01-01T00:00:00'), 'value': 20 },
      { 'date': new Date('2015-01-02T00:00:00'), 'value': 16 }
    ]
  }
]
```

Default chart is first example on [demo page](https://z3ut.github.io/interpolated-charts).

Source code for examples - /demo.

Package include internal @types for Typescript.

## Documentation

### Line Chart

#### Usage

```javascript
// create chart with custom config
const lineChart = line({ width: 900 });
// set property on existing chart
lineChart.curve(d3.curveCatmullRom);
// get d3 selection for chart container
const chartContainer = d3.select('.default-chart');
const lineChartData = [/* PathDataSet[] */];
// bind selection with data and call chart creation
chartContainer.datum(lineChartData).call(lineChart);

```

#### Chart data format
```typescript
interface PathDataSet {
  name: string;
  color?: string;
  data: { date: Date, value: number }[];
}
```

#### Events

chartEvents.chartMouseEnter - mouse entered chart boundary. Arguments - mouse coordinates x, y relative to chart;

chartEvents.chartMouseLeave - mouse leaved chart boundary. Arguments - mouse coordinates x, y relative to chart;

chartEvents.chartMouseMove - mouse moved inside chart boundary. Event treshhold (mouseMoveTimeTreshold, ms) - min time between events. Arguments - { x: number, y: number, selectedDate: Date, data: PointData[] }. data - array of closest chart points data based on mouse current position:

```typescript
interface PointData {
  // concrete values from PathDataSet and their coordinates on graph
  date: Date;
  value: number;
  x: number;
  y: number;
  // interpolated values, closest to mouse position
  interpolatedX: number;
  interpolatedY: number;
  interpolatedDate: Date;
  interpolatedValue: number;

  name: string;
  color: string;
}
```

chartEvents.chartMouseClick - mouse click inside chart boundary. Arguments - { x: number, y: number, selectedDate: Date, data: PointData[] }.

#### CSS

Chart grid lines css classes:

.line-chart .horizontal-grid-line, .line-chart .vertical-grid-line

#### Options

Name | Description | Type | Default
--- | --- | --- | ---
width | Chart total width | Number | 700
height | Chart total height | Number | 500
margin | Chart graph margin to outer bounds | { top: number, right: number, bottom: number, left: number } | { top: 20, right: 30, bottom: 40, left: 40 }
maxTimeRangeDifferenceToDraw | Max time in milliseconds to treat dataset points without breaking | Number | 1000 * 60 * 60 * 24 * 1.5 (1.5 days)
xAxisTimeFormat | Date tick format for chart X Axis | d3.tickFormat | undefined
yAxisValueFormat | Value tick format for chart Y Axis | d3.tickFormat | undefined
curve | Curve type for line interpolation. **Important**: value interpolation compute on chart resulted line and depend on this config value | d3.curve | d3.curveBasis
chartHeight | Chart graph actual heigth getter. Total height - (margin.top + margin.bottom) | Number |
chartWidth | Chart graph actual width getter. Total width - (margin.left + margin.right | Number |
interpolationMaxIterationCount | Interpolation cycle count. Computing will stop after N cycle or when Δx < accuracy **Important**: high value can slow preformance | Number | 50
interpolationAccuracy | Interpolation Δx accuracy for searching y value on svg path. Computing will stop after N cycle or when Δx < accuracy | Number | 0.005
mouseMoveTimeTreshold | Minimum time in milliseconds between chartMouseMove events | Number | 20
xAxisDateFrom | Chart X Axis start date | Date | undefined
xAxisDateTo | Chart X Axis end date | Date | undefined

### Bar chart

#### Usage

```javascript
// create bar chart
const barChart = bar();

const barChartContainer = d3.select('.bar-bar');
const barChartData = [/* PathDataSet[] */];
// bind selection with data and call chart creation
barChartContainer.datum(barChartData).call(barChart);
```

#### Chart data format
Array of
```typescript
interface StackBarData {
  name: string;
  backgroundColor?: string;
  data: {
    date: Date,
    color?: string,
    value: any
  }[];
}
```

#### Events

chartEvents.chartMouseEnter - mouse entered chart boundary. Arguments - mouse coordinates x, y relative to chart;

chartEvents.chartMouseLeave - mouse leaved chart boundary. Arguments - mouse coordinates x, y relative to chart;

chartEvents.chartMouseMove - mouse moved inside chart boundary. Event treshhold (mouseMoveTimeTreshold, ms) - min time between events. Arguments - { x: number, y: number, selectedDate: Date, data: MouseEventBarChartData[] }. data - array of closest chart points data based on mouse current position:

chartEvents.chartMouseClick - mouse click inside chart boundary. Arguments - { x: number, y: number, selectedDate: Date, data: MouseEventBarChartData[] }.

#### Options

Name | Description | Type | Default
--- | --- | --- | ---
width | Chart total width | Number | 700
height | Chart total height | Number | 120
margin | Chart graph margin to outer bounds | { top: number, right: number, 
setStackWidth | Function to compute stack width | Function | (chartWidth, numberOfBars) => chartWidth / numberOfBars - 20
maxTimeRangeDifferenceToDraw | Max time in milliseconds to treat dataset points without breaking | Number | 1000 * 60 * 60 * 24 * 1.5 (1.5 days)
stackTimeDiapason | Time diapason for one stack | Number | 1000 * 60 * 60 * 24
xAxisTimeFormat | Date tick format for chart X Axis | d3.tickFormat | undefined
yAxisValueFormat | Value tick format for chart Y Axis | d3.tickFormat | undefined
xAxisDateFrom | Chart X Axis start date | Date | undefined
xAxisDateTo | Chart X Axis end date | Date | undefined
yAxisValueFrom | Chart Y Axis start value | Number | undefined
yAxisValueTo | Chart Y Axis end value | Number | undefined

### Stack bar

#### Usage

```javascript
// create stack bar
const stackBarChart = stackBar();

const stackBarContainer = d3.select('.stack-bar');
const stackBarData = [/* StackBarData[] */];
// bind selection with data and call chart creation
stackBarContainer.datum(stackBarData).call(stackBarChart);
```

#### Chart data format
Array of
```typescript
interface PathDataSet {
  name: string;
  color?: string;
  data: { date: Date, value: number }[];
}
```

#### Events

chartEvents.chartMouseEnter - mouse entered chart boundary. Arguments - mouse coordinates x, y relative to chart;

chartEvents.chartMouseLeave - mouse leaved chart boundary. Arguments - mouse coordinates x, y relative to chart;

chartEvents.chartMouseMove - mouse moved inside chart boundary. Event treshhold (mouseMoveTimeTreshold, ms) - min time between events. Arguments - { x: number, y: number, selectedDate: Date, diapasonStart: Date, diapasonEnd: Date, data: MouseEventBarChartData[] }. data - array of closest chart points data based on mouse current position:

chartEvents.chartMouseClick - mouse click inside chart boundary. Arguments - { x: number, y: number, selectedDate: Date, data: StackBarEventData[] }.

#### Options

Name | Description | Type | Default
--- | --- | --- | ---
width | Chart total width | Number | 700
height | Chart total height | Number | 120
margin | Chart graph margin to outer bounds | { top: number, right: number, 
marginBetweenStacks | Vertical margin between multiple stack bars | Number | 0
backgroundColor | Chart background color | String | '#CCCCCC'
maxTimeRangeDifferenceToDraw | Max time in milliseconds to treat dataset points without breaking | Number | 1000 * 60 * 60 * 24 * 1.5 (1.5 days)
mouseMoveTimeTreshold | Minimum time in milliseconds between chartMouseMove events | Number | 20
xAxisTimeFormat | Date tick format for chart X Axis | d3.tickFormat | undefined
xAxisDateFrom | Chart X Axis start date | Date | undefined
xAxisDateTo | Chart X Axis end date | Date | undefined

### Plugins

#### Vertical divider

Display vertical line on chart.

##### Usage

```javascript
const lineChart = line({ height: 1000 });
// create plugin
const verticalDividerPlugin = verticalDivider();
// set divider height if chart height not default
verticalDividerPlugin
  .height(lineChart.chartHeight());
// subscribe plugin to chart events
lineChart
  .on(chartEvents.chartMouseEnter, (x, y) => verticalDividerPlugin.show())
  .on(chartEvents.chartMouseLeave, (x, y) => verticalDividerPlugin.remove())
  .on(chartEvents.chartMouseMove, (options) => verticalDividerPlugin.update(options));
// create line chart
d3.select('.interpolated-chart').datum([/* chart data */]).call(lineChart);
// select metadata container inside chart
const metadataContainer = d3.select('.interpolated-chart .metadata-container');
// call plugin creation
metadataContainer.datum([]).call(verticalDividerPlugin);
```

##### CSS

Divider line css class:

.line-chart .divider

##### Options

Name | Description | Type | Default
--- | --- | --- | ---
height | Divider line height | Number | 440

##### Methods

Name | Description | Arguments
--- | --- | ---
remove | Hide divider | None
show | Show divider | None
update | Set divider position | { x: number }

#### Markers

##### Usage

```javascript

const lineChart = line({ height: 1000 });
// create plugin with options
const markersPlugin = markers()
  .fill(data => {
    return data.interpolatedValue > 10 ? data.color : 'white'
  });
// set options
markersPlugin
  .radius(data => {
    return data.interpolatedValue > 10 ? 10 : 5
  })
// subscribe plugin to chart events
lineChart
  .on(chartEvents.chartMouseEnter, (x, y) => markersPlugin.show())
  .on(chartEvents.chartMouseLeave, (x, y) => markersPlugin.remove())
  .on(chartEvents.chartMouseMove, (options) => markersPlugin.update(options));
// create line chart
d3.select('.interpolated-chart').datum([/* chart data */]).call(lineChart);
// select metadata container inside chart
const metadataContainer = d3.select('.interpolated-chart .metadata-container');
// call plugin creation
metadataContainer.datum([]).call(markersPlugin);
```

##### Options

Name | Description | Type | Default
--- | --- | --- | ---
cx | Marker X position calculator | Function | data => data.interpolatedX || data.x
cy | Marker Y position calculator | Function | data => data.interpolatedY || data.y
radius | Marker radius calculator | Function | data => 5
fill | Marker fill color calculator | Function | data => 'white'
stroke | Marker stroke color calculator | Function | data => data.color || 'red'
strokeWidth | Marker stroke width calculator | Function | data => 2
sort | Marker sorting function. First value will be displayed on top of others | Function | (a, b) => 0

##### Methods

Name | Description | Arguments
--- | --- | ---
remove | Hide markers | None
show | Show markers | { data: ChartLinePointData[] }

#### Tooltip

Tooltip - html foreignObject in svg chart.

##### Usage

```javascript
const lineChart = line({ height: 1000 });
// create plugin with options
const verticalDividerPlugin = verticalDivider({ chartHeight: lineChart.chartheight() });
// set options
tooltipPlugin
  .chartWidth(lineChart.chartWidth())
  .valueFormatter(({ interpolatedValue }) => `${interpolatedValue.toFixed(1)}°C`);
// subscribe plugin to chart events
lineChart
  .on(chartEvents.chartMouseEnter, (x, y) => tooltipPlugin.show())
  .on(chartEvents.chartMouseLeave, (x, y) => tooltipPlugin.remove())
  .on(chartEvents.chartMouseMove, (options) => tooltipPlugin.update(options));
// create line chart
d3.select('.interpolated-chart').datum([/* chart data */]).call(lineChart);
// select metadata container inside chart
const metadataContainer = d3.select('.interpolated-chart .metadata-container');
// call plugin creation
metadataContainer.datum([]).call(tooltipPlugin);
```

##### CSS

.line-chart .tooltip

.line-chart .tooltip rect

.line-chart .tooltip .tooltip-container

.line-chart .tooltip .tooltip-header

.line-chart .tooltip .tooltip-header p

.line-chart .tooltip .circle

.line-chart .tooltip .topic

.line-chart .tooltip .topic-name

.line-chart .tooltip .topic-value

##### Options

Name | Description | Type | Default
--- | --- | --- | ---
chartHeight | Chart height (used to compute tooltip boundaries) | Number | 440
chartWidth | Chart width (used to compute tooltip boundaries) | Numner | 700
tooltipWidth | Tooltip fixed width | Number | 220
horizontalMouseMargin | Tooltip horizontal distance from mouse pointer | Number | 40
verticalBorderMargin | Tooltip min distance from chart top and bottom borders | Number | 10
headerFormatter | Tooltip header formatter function. Arguments - selected interpolated date and chart dataset values | Function | (selectedDate, data) => d3.timeFormat('%Y-%d-%m %H:%M:%S')(selectedDate)
topicFormatter | Tooltip path data description formatter | Function | (data) => data.name
valueFormatter | Tooltip path data value formatter | Function | (data) => d3.format('.1f')(data.interpolatedValue)
sort | Tooltip path data sorting function. First value will be displayed on top of tooltip | Function | (a, b) => 0

##### Methods

Name | Description | Arguments
--- | --- | ---
remove | Hide tooltip | None
show | Show tooltip | { x: number, y: number, selectedDate: Date, data: ChartLinePointData[] }

## TODO

- [x] Tests
- [ ] JSDoc
- [x] Documentation
- [ ] Display curve single points in missing data range and add them to tooltip