| commit | author | age | ||
| 83c3f6 | 1 | # Polar Area |
| SP | 2 | |
| 3 | Polar area charts are similar to pie charts, but each segment has the same angle - the radius of the segment differs depending on the value. | |
| 4 | ||
| 5 | This type of chart is often useful when we want to show a comparison data similar to a pie chart, but also show a scale of values for context. | |
| 6 | ||
| 7 | {% chartjs %} | |
| 8 | { | |
| 9 | "type": "polarArea", | |
| 10 | "data": { | |
| 11 | "labels": [ | |
| 12 | "Red", | |
| 13 | "Green", | |
| 14 | "Yellow", | |
| 15 | "Grey", | |
| 16 | "Blue" | |
| 17 | ], | |
| 18 | "datasets": [{ | |
| 19 | "label": "My First Dataset", | |
| 20 | "data": [11, 16, 7, 3, 14], | |
| 21 | "backgroundColor": [ | |
| 22 | "rgb(255, 99, 132)", | |
| 23 | "rgb(75, 192, 192)", | |
| 24 | "rgb(255, 205, 86)", | |
| 25 | "rgb(201, 203, 207)", | |
| 26 | "rgb(54, 162, 235)" | |
| 27 | ] | |
| 28 | }] | |
| 29 | }, | |
| 30 | } | |
| 31 | {% endchartjs %} | |
| 32 | ||
| 33 | ## Example Usage | |
| 34 | ||
| 35 | ```javascript | |
| 36 | new Chart(ctx, { | |
| 37 | data: data, | |
| 38 | type: 'polarArea', | |
| 39 | options: options | |
| 40 | }); | |
| 41 | ``` | |
| 42 | ||
| 43 | ## Dataset Properties | |
| 44 | ||
| 45 | The following options can be included in a polar area chart dataset to configure options for that specific dataset. | |
| 46 | ||
| 47 | | Name | Type | Description | |
| 48 | | ---- | ---- | ----------- | |
| 49 | | `backgroundColor` | `Color[]` | The fill color of the arcs in the dataset. See [Colors](../general/colors.md#colors) | |
| 50 | | `borderColor` | `Color[]` | The border color of the arcs in the dataset. See [Colors](../general/colors.md#colors) | |
| 51 | | `borderWidth` | `Number[]` | The border width of the arcs in the dataset. | |
| 52 | | `hoverBackgroundColor` | `Color[]` | The fill colour of the arcs when hovered. | |
| 53 | | `hoverBorderColor` | `Color[]` | The stroke colour of the arcs when hovered. | |
| 54 | | `hoverBorderWidth` | `Number[]` | The stroke width of the arcs when hovered. | |
| 55 | ||
| 56 | ## Config Options | |
| 57 | ||
| 58 | These are the customisation options specific to Polar Area charts. These options are merged with the [global chart default options](#default-options), and form the options of the chart. | |
| 59 | ||
| 60 | | Name | Type | Default | Description | |
| 61 | | ---- | ---- | ------- | ----------- | |
| 62 | | `startAngle` | `Number` | `-0.5 * Math.PI` | Starting angle to draw arcs for the first item in a dataset. | |
| 63 | | `animation.animateRotate` | `Boolean` | `true` | If true, the chart will animate in with a rotation animation. This property is in the `options.animation` object. | |
| 64 | | `animation.animateScale` | `Boolean` | `true` | If true, will animate scaling the chart from the center outwards. | |
| 65 | ||
| 66 | ## Default Options | |
| 67 | ||
| 68 | We can also change these defaults values for each PolarArea type that is created, this object is available at `Chart.defaults.polarArea`. Changing the global options only affects charts created after the change. Existing charts are not changed. | |
| 69 | ||
| 70 | For example, to configure all new polar area charts with `animateScale = false` you would do: | |
| 71 | ```javascript | |
| 72 | Chart.defaults.polarArea.animation.animateScale = false; | |
| 73 | ``` | |
| 74 | ||
| 75 | ## Data Structure | |
| 76 | ||
| 77 | For a polar area chart, datasets need to contain an array of data points. The data points should be a number, Chart.js will total all of the numbers and calculate the relative proportion of each. | |
| 78 | ||
| 79 | You also need to specify an array of labels so that tooltips appear correctly for each slice. | |
| 80 | ||
| 81 | ```javascript | |
| 82 | data = { | |
| 83 | datasets: [{ | |
| 84 | data: [10, 20, 30] | |
| 85 | }], | |
| 86 | ||
| 87 | // These labels appear in the legend and in the tooltips when hovering different arcs | |
| 88 | labels: [ | |
| 89 | 'Red', | |
| 90 | 'Yellow', | |
| 91 | 'Blue' | |
| 92 | ] | |
| 93 | }; | |
| 94 | ``` | |
