preserveAspectRatio
===================

O atributo **`preserveAspectRatio`** indica como um elemento com uma viewBox, fornecendo uma determinada proporção deve se ajustar a uma viewport com uma proporção diferente.

Because the aspect ratio of an SVG image is defined by the `viewBox (en-US)` attribute, if this attribute isn't set, the `preserveAspectRatio` attribute has no effect (*with one exception, the `<image>` element, as described below*).

Example
-------


```html
<svg viewBox="-1 -1 162 92" xmlns="https://www.w3.org/2000/svg">
  <defs>
    <path
 id="smiley"
 d="M50,10 A40,40,1,1,1,50,90 A40,40,1,1,1,50,10 M30,40 Q36,35,42,40 M58,40 Q64,35,70,40 M30,60 Q50,75,70,60 Q50,75,30,60" />
  </defs>

  <!-- (width>height) meet -->
  <svg
 preserveAspectRatio="xMidYMid meet"
 x="0"
 y="0"
 viewBox="0 0 100 100"
 width="20"
 height="10">
    <use href="#smiley" />
  </svg>
  <svg
 preserveAspectRatio="xMinYMid meet"
 x="25"
 y="0"
 viewBox="0 0 100 100"
 width="20"
 height="10">
    <use href="#smiley" />
  </svg>
  <svg
 preserveAspectRatio="xMaxYMid meet"
 x="50"
 y="0"
 viewBox="0 0 100 100"
 width="20"
 height="10">
    <use href="#smiley" />
  </svg>

  <!-- (width>height) slice -->
  <svg
 preserveAspectRatio="xMidYMin slice"
 x="0"
 y="15"
 viewBox="0 0 100 100"
 width="20"
 height="10">
    <use href="#smiley" />
  </svg>
  <svg
 preserveAspectRatio="xMidYMid slice"
 x="25"
 y="15"
 viewBox="0 0 100 100"
 width="20"
 height="10">
    <use href="#smiley" />
  </svg>
  <svg
 preserveAspectRatio="xMidYMax slice"
 x="50"
 y="15"
 viewBox="0 0 100 100"
 width="20"
 height="10">
    <use href="#smiley" />
  </svg>

  <!-- (width<height) meet -->
  <svg
 preserveAspectRatio="xMidYMin meet"
 x="75"
 y="0"
 viewBox="0 0 100 100"
 width="10"
 height="25">
    <use href="#smiley" />
  </svg>
  <svg
 preserveAspectRatio="xMidYMid meet"
 x="90"
 y="0"
 viewBox="0 0 100 100"
 width="10"
 height="25">
    <use href="#smiley" />
  </svg>
  <svg
 preserveAspectRatio="xMidYMax meet"
 x="105"
 y="0"
 viewBox="0 0 100 100"
 width="10"
 height="25">
    <use href="#smiley" />
  </svg>

  <!-- (width<height) slice -->
  <svg
 preserveAspectRatio="xMinYMid slice"
 x="120"
 y="0"
 viewBox="0 0 100 100"
 width="10"
 height="25">
    <use href="#smiley" />
  </svg>
  <svg
 preserveAspectRatio="xMidYMid slice"
 x="135"
 y="0"
 viewBox="0 0 100 100"
 width="10"
 height="25">
    <use href="#smiley" />
  </svg>
  <svg
 preserveAspectRatio="xMaxYMid slice"
 x="150"
 y="0"
 viewBox="0 0 100 100"
 width="10"
 height="25">
    <use href="#smiley" />
  </svg>

  <!-- none -->
  <svg
 preserveAspectRatio="none"
 x="0"
 y="30"
 viewBox="0 0 100 100"
 width="160"
 height="60">
    <use href="#smiley" />
  </svg>
</svg>
```


```
html,
body,
svg {
  height: 100%;
}
```


```
<svg viewBox="-1 -1 162 92" xmlns="https://www.w3.org/2000/svg">
  <defs>
    <path
 id="smiley"
 d="M50,10 A40,40,1,1,1,50,90 A40,40,1,1,1,50,10 M30,40 Q36,35,42,40 M58,40 Q64,35,70,40 M30,60 Q50,75,70,60 Q50,75,30,60" />
  </defs>

  <!-- (width>height) meet -->
  <rect x="0" y="0" width="20" height="10">
    <title>xMidYMid meet</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="20"
 height="10"
 preserveAspectRatio="xMidYMid meet"
 x="0"
 y="0">
    <use href="#smiley" />
  </svg>

  <rect x="25" y="0" width="20" height="10">
    <title>xMinYMid meet</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="20"
 height="10"
 preserveAspectRatio="xMinYMid meet"
 x="25"
 y="0">
    <use href="#smiley" />
  </svg>

  <rect x="50" y="0" width="20" height="10">
    <title>xMaxYMid meet</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="20"
 height="10"
 preserveAspectRatio="xMaxYMid meet"
 x="50"
 y="0">
    <use href="#smiley" />
  </svg>

  <!-- (width>height) slice -->
  <rect x="0" y="15" width="20" height="10">
    <title>xMidYMin slice</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="20"
 height="10"
 preserveAspectRatio="xMidYMin slice"
 x="0"
 y="15">
    <use href="#smiley" />
  </svg>

  <rect x="25" y="15" width="20" height="10">
    <title>xMidYMid slice</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="20"
 height="10"
 preserveAspectRatio="xMidYMid slice"
 x="25"
 y="15">
    <use href="#smiley" />
  </svg>

  <rect x="50" y="15" width="20" height="10">
    <title>xMidYMax slice</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="20"
 height="10"
 preserveAspectRatio="xMidYMax slice"
 x="50"
 y="15">
    <use href="#smiley" />
  </svg>

  <!-- (width<height) meet -->
  <rect x="75" y="0" width="10" height="25">
    <title>xMidYMin meet</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="10"
 height="25"
 preserveAspectRatio="xMidYMin meet"
 x="75"
 y="0">
    <use href="#smiley" />
  </svg>

  <rect x="90" y="0" width="10" height="25">
    <title>xMidYMid meet</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="10"
 height="25"
 preserveAspectRatio="xMidYMid meet"
 x="90"
 y="0">
    <use href="#smiley" />
  </svg>

  <rect x="105" y="0" width="10" height="25">
    <title>xMidYMax meet</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="10"
 height="25"
 preserveAspectRatio="xMidYMax meet"
 x="105"
 y="0">
    <use href="#smiley" />
  </svg>

  <!-- (width<height) slice -->
  <rect x="120" y="0" width="10" height="25">
    <title>xMinYMid slice</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="10"
 height="25"
 preserveAspectRatio="xMinYMid slice"
 x="120"
 y="0">
    <use href="#smiley" />
  </svg>

  <rect x="135" y="0" width="10" height="25">
    <title>xMidYMid slice</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="10"
 height="25"
 preserveAspectRatio="xMidYMid slice"
 x="135"
 y="0">
    <use href="#smiley" />
  </svg>

  <rect x="150" y="0" width="10" height="25">
    <title>xMaxYMid slice</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="10"
 height="25"
 preserveAspectRatio="xMaxYMid slice"
 x="150"
 y="0">
    <use href="#smiley" />
  </svg>

  <!-- none -->
  <rect x="0" y="30" width="160" height="60">
    <title>none</title>
  </rect>
  <svg
 viewBox="0 0 100 100"
 width="160"
 height="60"
 preserveAspectRatio="none"
 x="0"
 y="30">
    <use href="#smiley" />
  </svg>
</svg>
```


```
path {
  fill: yellow;
  stroke: black;
  stroke-width: 8px;
  stroke-linecap: round;
  stroke-linejoin: round;
  pointer-events: none;
}

rect:hover,
rect:active {
  outline: 1px solid red;
}
```

Syntax
------
```

preserveAspectRatio="<align> [<meetOrSlice>]"
```


Its value is made of one or two keywords: A required alignment value and an optional "meet or slice" reference as described below:

Alignment value

The alignment value indicates whether to force uniform scaling and, if so, the alignment method to use in case the aspect ratio of the `viewBox (en-US)` doesn't match the aspect ratio of the viewport. The alignment value must be one of the following keywords:

* **none**
 Do not force uniform scaling. Scale the graphic content of the given element non-uniformly if necessary such that the element's bounding box exactly matches the viewport rectangle. *Note that if* `<align>` *is* `none`*, then the optional* `<meetOrSlice>` *value is ignored*.
* **xMinYMin** - Force uniform scaling.
 Align the `<min-x>` of the element's `viewBox (en-US)` with the smallest X value of the viewport.
 Align the `<min-y>` of the element's `viewBox (en-US)` with the smallest Y value of the viewport.
* **xMidYMin** - Force uniform scaling.
 Align the midpoint X value of the element's `viewBox (en-US)` with the midpoint X value of the viewport.
 Align the `<min-y>` of the element's `viewBox (en-US)` with the smallest Y value of the viewport.
* **xMaxYMin** - Force uniform scaling.
 Align the `<min-x>+<width>` of the element's `viewBox (en-US)` with the maximum X value of the viewport.
 Align the `<min-y>` of the element's `viewBox (en-US)` with the smallest Y value of the viewport.
* **xMinYMid** - Force uniform scaling.
 Align the `<min-x>` of the element's `viewBox (en-US)` with the smallest X value of the viewport.
 Align the midpoint Y value of the element's `viewBox (en-US)` with the midpoint Y value of the viewport.
* **xMidYMid** (the default) - Force uniform scaling.
 Align the midpoint X value of the element's `viewBox (en-US)` with the midpoint X value of the viewport.
 Align the midpoint Y value of the element's `viewBox (en-US)` with the midpoint Y value of the viewport.
* **xMaxYMid** - Force uniform scaling.
 Align the `<min-x>+<width>` of the element's `viewBox (en-US)` with the maximum X value of the viewport.
 Align the midpoint Y value of the element's `viewBox (en-US)` with the midpoint Y value of the viewport.
* **xMinYMax** - Force uniform scaling.
 Align the `<min-x>` of the element's `viewBox (en-US)` with the smallest X value of the viewport.
 Align the `<min-y>+<height>` of the element's `viewBox (en-US)` with the maximum Y value of the viewport.
* **xMidYMax** - Force uniform scaling.
 Align the midpoint X value of the element's `viewBox (en-US)` with the midpoint X value of the viewport.
 Align the `<min-y>+<height>` of the element's `viewBox (en-US)` with the maximum Y value of the viewport.
* **xMaxYMax** - Force uniform scaling.
 Align the `<min-x>+<width>` of the element's `viewBox (en-US)` with the maximum X value of the viewport.
 Align the `<min-y>+<height>` of the element's `viewBox (en-US)` with the maximum Y value of the viewport.

Meet or slice reference

The meet or slice reference is optional and, if provided, must be one of the following keywords:

* **meet** (*the default*) - Scale the graphic such that:
    + aspect ratio is preserved
    + the entire `viewBox (en-US)` is visible within the viewport
    + the `viewBox (en-US)` is scaled up as much as possible, while still meeting the other criteriaIn this case, if the aspect ratio of the graphic does not match the viewport, some of the viewport will extend beyond the bounds of the `viewBox (en-US)` (i.e., the area into which the `viewBox (en-US)` will draw will be smaller than the viewport).
* **slice** - Scale the graphic such that:
    + aspect ratio is preserved
    + the entire viewport is covered by the `viewBox (en-US)`
    + the `viewBox (en-US)` is scaled down as much as possible, while still meeting the other criteriaIn this case, if the aspect ratio of the `viewBox (en-US)` does not match the viewport, some of the `viewBox (en-US)` will extend beyond the bounds of the viewport (i.e., the area into which the `viewBox (en-US)` will draw is larger than the viewport).

Elements
--------

Seven elements are using this attribute: `<svg>`, `<symbol>`, `<image>`, `<feImage>` (en-US), `<marker>`, `<pattern>`, and `<view>`.

### feImage

For `<feImage>` (en-US), `preserveAspectRatio` defines how the referenced image should fit in the rectangle define by the `<feImage>` element.

| Value | **<align> <meetOrSlice>?** |
| --- | --- |
| Default value | `xMidYMid` `meet` |
| Animatable | Yes |

### image

For `<image>`, `preserveAspectRatio` defines how the referenced image should fit in the rectangle define by the `<image>` element.

| Value | **<align> <meetOrSlice>?** |
| --- | --- |
| Default value | `xMidYMid` `meet` |
| Animatable | Yes |

### marker

For `<marker>`, `preserveAspectRatio` indicates if a uniform scaling must be performed to fit the element viewport.

| Value | **<align> <meetOrSlice>?** |
| --- | --- |
| Default value | `xMidYMid` `meet` |
| Animatable | Yes |

### pattern

For `<pattern>`, `preserveAspectRatio` indicates if a uniform scaling must be performed to fit the element viewport.

| Value | **<align> <meetOrSlice>?** |
| --- | --- |
| Default value | `xMidYMid` `meet` |
| Animatable | Yes |

### svg

For `<svg>`, `preserveAspectRatio` indicates if a uniform scaling must be performed to fit the element viewport.

| Value | **<align> <meetOrSlice>?** |
| --- | --- |
| Default value | `xMidYMid` `meet` |
| Animatable | Yes |

### symbol

For `<symbol>`, `preserveAspectRatio` indicates if a uniform scaling must be performed to fit the element viewport.

| Value | **<align> <meetOrSlice>?** |
| --- | --- |
| Default value | `xMidYMid` `meet` |
| Animatable | Yes |

### view

For `<view>`, `preserveAspectRatio` indicates if a uniform scaling must be performed to fit the element viewport.

| Value | **<align> <meetOrSlice>?** |
| --- | --- |
| Default value | `xMidYMid` `meet` |
| Animatable | Yes |

Especificações
--------------

| Specification |
| --- |
| Filter Effects Module Level 1 # element-attrdef-feimage-preserveaspectratio |
| Scalable Vector Graphics (SVG) 2 # PreserveAspectRatioAttribute |