# Container

> Size, padding, alignment, background, border and shadow for one child. A Pyzed component for Python desktop GUIs, with examples and its API.

Source: https://albakore.github.io/pyzed/library/container/

:::tip[In plain words]
A box around one thing, to give it a size, a margin, a background or a border.
:::

Wraps one child to give it a size, padding and alignment, and to draw a background (color or gradient), a border, rounded corners and a shadow. `pz.center(child)` is a container that centers its child in all the available space.

`pz.container` · Category: [Layout](https://albakore.github.io/pyzed/library/#layout) · [Full reference →](https://albakore.github.io/pyzed/reference/widgets/#container)

**Code:**

```python
t = pz.theme.current()
pz.row([
    pz.container(ui.label("padding + bg"), padding=16, bg=t.element, radius=8),
    pz.container(ui.label("border"), padding=16, border_color=t.accent, border_width=2, radius=8),
    pz.container(ui.label("shadow", color="#ffffff"), padding=16, radius=12,
                 gradient=(135, ["#7c3aed", "#3b82f6"]),
                 shadow=("#00000066", (0, 6), 18)),
], spacing=16, align="center")
```

## When to use

- Whenever a widget needs a box: cards, colored areas, fixed sizes, centering.

## Usage

```python
import pyzed as pz
from pyzed import ui

t = pz.theme.current()
pz.row([
    pz.container(ui.label("padding + bg"), padding=16, bg=t.element, radius=8),
    pz.container(ui.label("border"), padding=16, border_color=t.accent, border_width=2, radius=8),
    pz.container(ui.label("shadow", color="#ffffff"), padding=16, radius=12,
                 gradient=(135, ["#7c3aed", "#3b82f6"]),
                 shadow=("#00000066", (0, 6), 18)),
], spacing=16, align="center")
```

## Variants

:::note[About these captures]
Each capture is recorded by pyzed itself, off-screen at 2x, in One Dark or One Light to match this site's theme, and cropped to the component so it shows at its real size. The pointer hovers, presses or types into it; a component that does not react to the pointer cycles through a few themes. With reduced motion you see the first frame. Open **Code** under a capture to see the snippet that draws it; free names such as `on_save` stand for your own callbacks.
:::

### Box

```python
pz.container(ui.label("padding + bg"), padding=16, bg=pz.theme.current().element, radius=8)
```

```python
pz.container(ui.label("border"), padding=16, border_color=pz.theme.current().accent,
             border_width=2, radius=8)
```

```python
pz.container(ui.label("pill"), padding=(6, 16), bg=pz.theme.current().element, radius=999)
```

### Paint

```python
pz.container(ui.label("gradient", color="#ffffff"), padding=16, radius=10,
             gradient=(135, ["#7c3aed", "#3b82f6"]))
```

```python
pz.container(ui.label("shadow"), padding=16, radius=10, bg=pz.theme.current().elevated,
             shadow=("#00000066", (0, 6), 18))
```

### Alignment

```python
pz.container(ui.label("centered"), center=True, width=220, height=90,
             border_color=pz.theme.current().border, border_width=1, radius=8)
```

```python
pz.container(ui.label("bottom right"), align_x="end", align_y="end", padding=8,
             width=220, height=90, border_color=pz.theme.current().border, border_width=1, radius=8)
```

## Examples

### Centering

`pz.center` (or `center=True`) centers the child in the space it gets.

**Code:**

```python
pz.container(pz.center(ui.label("centered")), width=360, height=120,
             border_color=pz.theme.current().border, border_width=1, radius=8)
```

## Events

Container has no events of its own: it shows what you give it. Like every widget it also has the **18 common events** (`click`, `double_click`, `right_click`, `mouse_enter`, `drag`, `key_down`, `resize`…), attached with `.on(...)`: see [Events](https://albakore.github.io/pyzed/guides/events/) and [Events of every component](https://albakore.github.io/pyzed/library/events/).

## Properties and API

### `pz.container`

```python
container(
    content=None,
    *,
    padding=None,
    width=None,
    height=None,
    max_width=None,
    max_height=None,
    align_x=None,
    align_y=None,
    center=False,
    bg=None,
    color=None,
    border_color=None,
    border_width=0.0,
    radius=None,
    shadow=None,
    clip=False,
    gradient=None,
)
```

Wraps a child to give it size, alignment, background, border, radius and shadow.

| Property | Default | Description |
| --- | --- | --- |
| `content` | `None` | The child (or `None` for an empty box, handy as a colored rectangle). |
| `padding` | `None` | Inner padding: `8`, `(vertical, horizontal)` or `(top, right, bottom, left)`. |
| `width` | `None` | Width: pixels, `"fill"`, `"shrink"` or `"fill:N"` (proportion). |
| `height` | `None` | Height: pixels, `"fill"`, `"shrink"` or `"fill:N"` (proportion). |
| `max_width` | `None` | Maximum width in pixels. |
| `max_height` | `None` | Maximum height in pixels. |
| `align_x` | `None` | Horizontal alignment: `"start"`/`"left"`, `"center"`, `"end"`/`"right"`. |
| `align_y` | `None` | Vertical alignment: `"start"`/`"top"`, `"center"`, `"end"`/`"bottom"`. |
| `center` | `False` | Centers the content on both axes and fills all the space. |
| `bg` | `None` | Background color (`"#rrggbb[aa]"`, `(r, g, b[, a])` or `"transparent"`). |
| `color` | `None` | Text or icon color. |
| `border_color` | `None` | Border color. |
| `border_width` | `0.0` | Border width in pixels. |
| `radius` | `None` | Corner radius: a number or `(top_left, top_right, bottom_right, bottom_left)`. |
| `shadow` | `None` | Shadow: `(color, (dx, dy), blur)`. |
| `clip` | `False` | Clips content that overflows the bounds. |
| `gradient` | `None` | Linear background gradient: `(angle, [colors])` or `(angle, [(position, color), ...])`. |

[Full reference →](https://albakore.github.io/pyzed/reference/widgets/#container)

### `pz.center`

```python
center(content, **kwargs)
```

Centers `content` in all the available space. Equivalent to `container(content, center=True)`.

| Property | Default | Description |
| --- | --- | --- |
| `content` | *required* | Content: a `Widget`, a string or a number (converted to text). |
| `**kwargs` | — | Any `container` parameter. |

[Full reference →](https://albakore.github.io/pyzed/reference/widgets/#center)

## Related

- [Card](https://albakore.github.io/pyzed/library/card/): A bordered surface with an optional title and actions.
- [Stack](https://albakore.github.io/pyzed/library/stack/): Layers children on top of each other; `pin` places one at x, y.
- [Row](https://albakore.github.io/pyzed/library/row/): Lays out children horizontally.