How do I stretch an image to fit the whole background (100% height x 100% width) in Flutter?

Question

I have an image that doesn't match the aspect ratio of my device's screen. I want to stretch the image so that it fully fills the screen, and I don't want to crop any part of the image.

CSS has the concept of percentages, so I could just set height and width to 100%. But it doesn't seem like Flutter has that concept, and it's bad to just hard code the height and width, so I'm stuck.

Here's what I have (I'm using a Stack since I have something in the foreground of the image):

Widget background = new Container(
  height: // Not sure what to put here!
  width: // Not sure what to put here!
  child: new Image.asset(
    asset.background,
    fit: BoxFit.fill, // I thought this would fill up my Container but it doesn't
  ),
);

return new Stack(
  children: <Widget>[
    background,
    foreground,
  ],
);

Coel

Answer 1

To make an Image fill its parent, simply wrap it into a FittedBox:

FittedBox(
  child: Image.asset('foo.png'),
  fit: BoxFit.fill,
)

FittedBox here will stretch the image to fill the space. (Note that this functionality used to be provided by BoxFit.fill, but the API has meanwhile changed such that BoxFit no longer provides this functionality. FittedBox should work as a drop-in replacement, no changes need to be made to the constructor arguments.)

---

Alternatively, for complex decorations you can use a Container instead of an Image – and use decoration/foregroundDecoration fields.

To make the Container will its parent, it should either:

• have no child
• have alignment property not null

Here's an example that combines two images and a Text in a single Container, while taking 100% width/height of its parent:

Container(
  foregroundDecoration: const BoxDecoration(
    image: DecorationImage(
        image: NetworkImage(
            'https://p6.storage.canalblog.com/69/50/922142/85510911_o.png'),
        fit: BoxFit.fill),
  ),
  decoration: const BoxDecoration(
    image: DecorationImage(
        alignment: Alignment(-.2, 0),
        image: NetworkImage(
            'http://www.naturerights.com/blog/wp-content/uploads/2017/12/Taranaki-NR-post-1170x550.png'),
        fit: BoxFit.cover),
  ),
  alignment: Alignment.bottomCenter,
  padding: EdgeInsets.only(bottom: 20),
  child: Text(
    "Hello World",
    style: Theme.of(context)
        .textTheme
        .display1
        .copyWith(color: Colors.white),
  ),
),

Eicher

How can I a add a fade in image widget here? I don't think we can. – Sublingual

Ty, I have I think newer version and I did: SizedBox.expand(child: Image.asset("assets/bg.png", fit: BoxFit.fill)) – Clo

so why is the fit parameter still present in the various Image constructors? What's the use, if it has been de facto replaced by FittedBox? – Thrifty

For me, it didn't work with FittedBox. But @Clo 's comment to use SizedBox.expand() did work for me. Thanks – Bunnell

Answer 2

The following will fit the image to 100% of container width while the height is constant. For local assets, use AssetImage

Container(
  width: MediaQuery.of(context).size.width,
  height: 100,
  decoration: BoxDecoration(
    image: DecorationImage(
      fit: BoxFit.fill,
      image: NetworkImage("https://picsum.photos/250?image=9"),
    ),
  ),
)

---

Image fill modes:

• Fill - Image is stretched

  fit: BoxFit.fill
  

  ---

• Fit Height - image kept proportional while making sure the full height of the image is shown (may overflow)

  fit: BoxFit.fitHeight
  

  ---

• Fit Width - image kept proportional while making sure the full width of the image is shown (may overflow)

  fit: BoxFit.fitWidth
  

  ---

• Cover - image kept proportional, ensures maximum coverage of the container (may overflow)

  fit: BoxFit.cover
  

  ---

• Contain - image kept proportional, minimal as possible, will reduce it's size if needed to display the entire image

  fit: BoxFit.contain
  

Womack

Never use MediaQuery to make an widget fill its parent. That's not what you want – Gridley

@RémiRousselet can you explain reason for that (or give me a link to that reason) .Thanks. – Divulsion

I will go with "fit: BoxFit.cover,". Thanks. – Rakes

This deserves an extra up-vote for the awesome examples of each of the fit modes. – Mylohyoid

Answer 3

Inside your Stack, you should wrap your background widget in a Positioned.fill.

return new Stack(
  children: <Widget>[
    new Positioned.fill(
      child: background,
    ),
    foreground,
  ],
);

Coel

thanks for this Stack widget overlay, I were searching for this widget in Flutter, by using this it is possible for me to Show Container above Image, cheers! – Restrainer

Answer 4

For me, to develop for web, works fine the following:

Image(
  image: AssetImage('lib/images/portadaSchamann5.png'),
  alignment: Alignment.center,
  height: double.infinity,
  width: double.infinity,
  fit: BoxFit.fill,
),

Tribute

this seems to be canon too: SizedBox.expand uses double.infinity for its values too. – Slimsy

Answer 5

Might not be exactly what the OP was looking for, but this page is where I found myself after looking for the problem, so sharing this for everyone with similar issue :)

Stack's fit property did the trick for my needs. Otherwise Image inside (OctoImageIn my case) was padded and providing other Image.fit values did not give any effect.

Stack(
  fit: StackFit.expand, 
  children: [
    Image(
      image: provider,
      fit: BoxFit.cover,
    ),
    // other irrelevent children here
  ]
);

Dispirit

Answer 6

Your Question contains the first step, but you need width and height. you can get the width and height of the screen. Here is a small edit

//gets the screen width and height
double Width = MediaQuery.of(context).size.width;
double Height = MediaQuery.of(context).size.height;

Widget background = new Image.asset(
  asset.background,
  fit: BoxFit.fill,
  width: Width,
  height: Height,
);

return new Stack(
  children: <Widget>[
    background,
    foreground,
  ],
);

You can also use Width and Height to size other objects based on screen size.

ex: width: Height/2, height: Height/2 //using height for both keeps aspect ratio

Loxodrome

fit: BoxFit.fill, on Image was a life saver, thanks :) – Kubiak

Answer 7

The best example for this question I found on this page: https://flutterbeads.com/set-background-image-in-flutter/

By using BoxDecoration and DecorationImage:

Container(
  constraints: BoxConstraints.expand(),
  decoration: const BoxDecoration(
    image: DecorationImage(
        image: AssetImage("assets/images/cat2.jpg"), 
        fit: BoxFit.cover),
  )

Papist

Answer 8

I think that for your purpose Flex could work better than Container():

new Flex(
    direction: Axis.vertical,
    children: <Widget>[
      Image.asset(asset.background)
    ],
   )

Cavorelievo

You just saved my life - :) Perfect for me. – Stopper

Answer 9

This should work,

Image.asset('assets/bg.jpg',fit: BoxFit.cover,),

Inappetence

This. You can also BoxFit.fitWidth, fitHeight and others. – Cascade

Answer 10

None of the above answers worked for me. And since there is no accepted answer, I found the following extended my image from horizontal edge to horizontal edge:

Container ( width: MediaQuery
                    .of(context)
                    .size
                    .width,
                child: 
                  Image.network(my_image_name, fit: BoxFit.fitWidth )
              )

Schaerbeek

This answer works when you only want to fit the image to full width without stretching it – Trilley

Answer 11

Visit https://youtu.be/TQ32vqvMR80 OR

For example if parent contrainer has height: 200, then

Container(
            decoration: BoxDecoration(
              image: DecorationImage(
                image: NetworkImage('url'),
                fit: BoxFit.cover,
              ),
            ),
          ),

Compliancy

Answer 12

For filling, I sometimes use SizedBox.expand

Unprecedented

Answer 13

I set width and height of a container to double.infinity like so:

Container(
        width: double.infinity,
        height: double.infinity,
        child: //your child
)

Abductor

This won't work for the child of the container, just the container. – Shakta

Answer 14

This will work if you want to add a fit background image in Flutter:

class Myname extends StatelessWidget {
  const Myname({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: SafeArea(
        child: Container(
          decoration: const BoxDecoration(
            image: DecorationImage(
              image: AssetImage("assets/aj.jpg"),
              fit: BoxFit.cover,
            ),
          ),
          child: Scaffold(
            backgroundColor: Colors.transparent,
            body: Column(),
          ),
        ),
      ),
    );
  }
}

Now you can add the rest of the things inside the Column()

Vitebsk

Answer 15

I ran into problems with just an FittedBox so I wrapped my Image in an LayoutBuilder:

LayoutBuilder( 
   builder: (_, constraints) => Image(
      fit: BoxFit.fill,
      width: constraints.maxWidth,
      image: AssetImage(assets.example),
   ),
)

This worked like a charm and I suggest you give it a try.
Of course you can use height instead of width, this is just what I used.

Fain

Answer 16

For me, using Image(fit: BoxFit.fill ...) worked when in a bounded container.

Baroque

Answer 17

This worked for me

class _SplashScreenState extends State<SplashScreen> {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: FittedBox(
        child: Image.asset("images/my_image.png"),
        fit: BoxFit.fill,
      ),);
  }
}

Eternal

Answer 18

I didn’t find answer in this post, But I found the fix:

        Positioned(
            bottom: 0,
            top: 0,
            child: Image.asset(
          'assets/images/package_bg.png',
        )),

This code make image fit to height on the stack.

Storekeeper

Answer 19

Try setting contentPadding

ListTile(
  contentPadding: EdgeInsets.all(0.0),
  ...
)

Struggle