如何使用 SwiftUI 调整图像大小？

Question

I have a large image in Assets.xcassets. How to resize this image with SwiftUI to make it small?

I tried to set frame but it doesn't work:

Image(room.thumbnailImage)
    .frame(width: 32.0, height: 32.0)

Answer 1

You should use .resizable() before applying any size modifications on an Image .

Image(room.thumbnailImage)
    .resizable()
    .frame(width: 32.0, height: 32.0)

Answer 2

How about this:

struct ResizedImage: View {
    var body: some View {
        Image("myImage")
            .resizable()
            .scaledToFit()
            .frame(width: 200, height: 200)
    }
}

The image view is 200x200, but the image maintains the original aspect ratio (rescaling within that frame).

Answer 3

In SwiftUI, use the .resizable() method to resize an image. By using .aspectRatio() and specifying a ContentMode , you can either "Fit" or "Fill" the image, as appropriate.

For example, here is code that resizes the image by fitting:

Image("example-image")
.resizable()
.aspectRatio(contentMode: .fit)

Answer 4

Expanding on @rraphael's answer and comments:

As of Xcode 11 beta 2, you can scale an image to arbitrary dimensions, while maintaining the original aspect ratio by wrapping the image in another element.

eg

struct FittedImage: View
{
    let imageName: String
    let width: CGFloat
    let height: CGFloat

    var body: some View {
        VStack {
            Image(systemName: imageName)
                .resizable()
                .aspectRatio(1, contentMode: .fit)
        }
        .frame(width: width, height: height)
    }
}


struct FittedImagesView: View
{
    private let _name = "checkmark"

    var body: some View {

        VStack {

            FittedImage(imageName: _name, width: 50, height: 50)
            .background(Color.yellow)

            FittedImage(imageName: _name, width: 100, height: 50)
            .background(Color.yellow)

            FittedImage(imageName: _name, width: 50, height: 100)
            .background(Color.yellow)

            FittedImage(imageName: _name, width: 100, height: 100)
            .background(Color.yellow)

        }
    }
}

Results

(For some reason, the image is showing as a bit blurry. Rest assured that the real output is sharp.)

Answer 5

To render the image with a fit aspect ratio and clipping to bounds, use this code:

struct ContentView: View {
    var body: some View {
        Image("donuts")
            .resizable()
            .scaledToFill()
            .frame(width: 200, height: 200)
            .border(Color.pink)
            .clipped()
    }
}

The result:

Answer 6

You need to add the .resizable modifier, to be able to change the size of the image

The code then would look like this:

Image(room.thumbnailImage)
    .resizable()
    .frame(width: 32.0, height: 32.0)

Answer 7

struct AvatarImage: View {
    var body: some View {

            Image("myImage")
                .resizable()
                .scaledToFill() // <=== Saves aspect ratio
                .frame(width: 60.0, height:60)
                .clipShape(Circle())

    }
}

Answer 8

Another approach is to use the scaleEffect modifier:

Image(room.thumbnailImage)
    .resizable()
    .scaleEffect(0.5)

Answer 9

Well, It's seems pretty easy in SwiftUI / Following the demo they given : https://developer.apple.com/videos/play/wwdc2019/204

struct RoomDetail: View {
     let room: Room
     var body: some View {

     Image(room.imageName)
       .resizable()
       .aspectRatio(contentMode: .fit)
 }

Hope it helps.

Answer 10

Since we shouldn't hardcode/fix the image size. Here is a better way to provide range to adjust according to the screen's resolution on different devices.

Image("ImageName Here")
       .resizable()
       .frame(minWidth: 60.0, idealWidth: 75.0, maxWidth: 95.0, minHeight: 80.0, idealHeight: 95.0, maxHeight: 110.0, alignment: .center)
       .scaledToFit()
       .clipShape(Capsule())
       .shadow(color: Color.black.opacity(5.0), radius: 5, x: 5, y: 5)

Answer 11

If you want to use aspect ratio with resizing then you can use following code:

Image(landmark.imageName).resizable()
                .frame(width: 56.0, height: 56.0)
                .aspectRatio(CGSize(width:50, height: 50), contentMode: .fit)

Answer 12

Note : My image name is img_Logo and you can change image name define image properties this:

 VStack(alignment: .leading, spacing: 1) {
                        //Image Logo Start
                        Image("img_Logo")
                            .resizable()
                            .padding(.all, 10.0)
                            .frame(width: UIScreen.main.bounds.width * 0.4, height: UIScreen.main.bounds.height * 0.2)
                        //Image Logo Done
                    }

Answer 13

By default, image views automatically size themselves to their contents, which might make them go beyond the screen. If you add the resizable() modifier then the image will instead automatically be sized so that it fills all the available space:

Image("example-image")
    .resizable()

However, that may also cause the image to have its original aspect ratio distorted, because it will be stretched in all dimensions by whatever amount is needed to make it fill the space.

If you want to keep its aspect ratio you should add an aspectRatio modifier using either .fill or .fit, like this:

Image("example-image")
    .resizable()
    .aspectRatio(contentMode: .fit)

Answer 14

It is very important to understand logical structure of code. Like in SwiftUI an image is not resizable by default. Thus, to resize any image you have to make it resizable by applying the .resizable() modifier immediately after you declare an Image view.

Image("An Image file name")
    .resizable()

Answer 15

Use .resizable() method after image name. Make sure usage of .resizable() need to declare before any modification.

like this:

Image("An Image file name")
    .resizable()
//add other modifications here 

Answer 16

To make an image scales to fit the current view, we use the resizable() modifier, which resizes an image to fit available space.

for Example:

 Image("ImageName")
            .resizable()
            .aspectRatio(contentMode: .fit)
            .frame(width: 200, height: 200, alignment: .center)

Answer 17

Image(systemName: "person.fill")
  .font(.system(size: 13))

will also work if you are using systemName .

Answer 18

If you want to resize the image in swiftUI just use the following code :

import SwiftUI

    struct ImageViewer : View{
        var body : some View {
            Image("Ssss")
            .resizable()
            .frame(width:50,height:50)
        }
    }

But here is problem with this. If you add this Image inside a Button, the Image will not be shown, just a block of blue colour would be there. To solve this issue, just do this :

import SwiftUI

struct ImageViewer : View{
    var body : some View {
        Button(action:{}){
        Image("Ssss")
        .renderingMode(.original)
        .resizable()
        .frame(width:50,height:50)
    }
   }
}

Answer 19

You can define Image Properties as follow:-

   Image("\(Image Name)")
   .resizable() // Let you resize the images
   .frame(width: 20, height: 20) // define frame size as required
   .background(RoundedRectangle(cornerRadius: 12) // Set round corners
   .foregroundColor(Color("darkGreen"))      // define foreground colour 

Answer 20

You can use resizable() property, but keep it in mind that you cannot use resizable in a common modifier so you have to use Image extension to achieve it.

extension Image {
    func customModifier() -> some View {
        self
            .resizable()
            .aspectRatio(contentMode: .fit)
    }

Answer 21

It is suggested to use the following code to match multiple screen sizes:

Image("dog")
    .resizable()
    .frame(minWidth: 200, idealWidth: 400, maxWidth: 600, minHeight: 100, idealHeight: 200, maxHeight: 300, alignment: .center)

Answer 22

You also can use:

Image("Example")
   .scaleEffect(NumberWithSizeBetweenZeroAndOne)

Answer 23

SwiftUI provided us .resizable() modifier that will let SwiftUI to resizes an image to fit its space

struct ContentView: View {
    var body: some View {
        Image("home")
            .antialiased(true) //for smooth edges for scale to fill
            .resizable() // for resizing
            .scaledToFill() // for filling image on ImageView
    }
}

Answer 24

Here, it's a view of the mountains and this is my image.

Let's create a simple image view inside the code.

var body: some View {
    Image(“mountains”)
}

The result doesn't look well.

Let's resize it and use a scale to fit at first

var body: some View {
    Image(“mountains”)
        .resizable()
        .scaledToFit()
}

Now it looks much better.

Notice that there is white space because the image is taken vertically and the screen is horizontal.

Not use size to fill.

Some part of the image is beyond the screen but it looks better than the default without any scale.

If you click on the image inside Preview you'll see how big is the image. That blue lines are the border of image.

Answer 25

As they said you have to use for resizing an Image on SwiftUI :

Call an image -> Image("somename") then, you add -> .resizable()

and now the image is resizable

next you can apply .aspectRatio to fit dimension or just fill the frame.

Example for simple usage of resizable:

Image("somename")
.resizable()
.frame(width: 50px, height: 50px) 

Answer 26

Image(room.thumbnailImage)
    .resizable()
    .frame(width: 32.0, height: 32.0,alignment: .center)

In SwiftUI .resizable() attribute helps to resize an image. After that we can give some custom size.

Answer 27

Image(room.thumbnailImage) .frame(width: 32.0, height: 32.0)

Add resizable and frame

.resizable() .frame( maxWidth: 600, maxHeight: 300,)

Answer 28

Use the font modifier with a dynamic type on an Image view:

Image(systemName: "nose")
        .font(.largeTitle)

Answer 29

204

If we have a large image in Assets.xcassets. then for resize this image with SwiftUI to make it small firstly we must use the resizable() and then use frame() .

Image(room.thumbnailImage)
.resizable()
    .frame(width: 32.0, height: 32.0)

Answer 30

You have to make the image resizable then you can apply a frame for the image size you want.

Image("YOUR IMAGE NAME")
    .resizable()
    .frame(width: 32.0, height: 32.0)