内边距(Padding)

Padding values in Chart options can be supplied in a couple of different formats.

## Number
If this value is a number, it is applied to all sides (left, top, right, bottom).

For example, defining a 20px padding to all sides of chart:

```javascript
let chart = new Chart(ctx, {
    type: 'line',
    data: data,
    options: {
        layout: {
            padding: 20
        }
    }
});
```

## {top, left, bottom, right} object
If this value is an object, the left property defines the left padding. Similarly the right, top and bottom properties can also be specified. Omitted properties default to 0.

Let's say you wanted to add 50px of padding to the left side of the chart canvas, you would do:

```javascript
let chart = new Chart(ctx, {
    type: 'line',
    data: data,
    options: {
        layout: {
            padding: {
                left: 50
            }
        }
    }
});
```

## {x, y} object
This is a shorthand for defining left/right and top/bottom to the same values.

For example, 10px left / right and 4px top / bottom padding on a Radial Linear Axis tick backdropPadding:

```javascript
let chart = new Chart(ctx, {
    type: 'radar',
    data: data,
    options: {
        scales: {
          r: {
            ticks: {
              backdropPadding: {
                  x: 10,
                  y: 4
              }
            }
        }
    }
});
```