The Complete Guide to CSS object-fit Property
Published: 2024-07-14 00:05:53

# The Complete Guide to CSS object-fit: Key to Handling Images on the Web

## Introduction: Why You Need to Know object-fit

Dealing with images in web development has always been a challenging task. How can we consistently display images of various sizes and ratios? This is where the CSS `object-fit` property plays a crucial role.

Understanding `object-fit` means more than just displaying images correctly. Recently, many cloud services that automatically adjust the size of user-uploaded images have been offering `object-fit` as an option. Therefore, if you don't understand the exact behavior of `object-fit`, you might unintentionally provide a negative user experience during the image optimization process.

## Basic Concepts of object-fit

The `object-fit` property determines how an image will be cropped or scaled to fit within the specified size (container size) of an `<img>` or `<video>` tag, in relation to the original image size.

An important point to note is that when only `width` or `height` is specified, the other dimension is automatically determined based on the original image ratio. In this case, for all `object-fit` values except `scale-down` and `none`, the image will fill the container size while maintaining its aspect ratio. However, with `scale-down` and `none`, if the container size is larger than the image size, the image will maintain its original size without stretching.

## object-fit Values and Their Effects

### 1. contain

```
      Container
+--------------------+
|        Image       |
|:------------------:|
|:                  :|
|:                  :|
|:                  :|
|:                  :|
|:------------------:|
|                    |
+--------------------+
```

- Adjusts the image to be fully visible
- Maintains image aspect ratio
- May result in empty space within the container

### 2. cover

```
         Image
:######################:
:#                    #:
:#     Container      #:
:#  +------------+    #:
:#  |            |    #:
:#  |            |    #:
:#  |            |    #:
:#  +------------+    #:
:#                    #:
:######################:
```

- Completely fills the container
- Maintains image aspect ratio
- May crop parts of the image

### 3. fill

- Completely fills the container
- Ignores image aspect ratio (may distort the image)

### 4. none

- Maintains original image size
- Ignores container size (image may be clipped)

### 5. scale-down

- Displays the image at the smaller size between `none` and `contain`
- Prevents the image from stretching

## Image Widget in Flitter

The Flitter library also provides an Image widget that implements the behavior of `object-fit`. Flitter's Image widget is designed to behave as similarly as possible to the native HTML `<img>` tag and supports various `object-fit` options.

```typescript
Image({
  src: 'https://flitter.dev/examples/object-fit/profile.jpg',
  width: 750,
  height: 250,
  objectFit: 'none'
})
```

If you want to see various examples of `object-fit`, visit the following URL: [https://flitter.dev/examples/object-fit](https://flitter.dev/examples/object-fit)

## Conclusion

The `object-fit` property is a powerful tool for handling images on the web. By properly understanding and using it, developers can effectively manage images of various sizes and ratios, providing users with a consistent visual experience. Understanding `object-fit` becomes even more important when using image optimization services. We hope this guide helps you handle images more effectively in your web projects.