ImageRenderer is one other new API for SwiftUI that comes with iOS 16. It lets you simply convert any SwiftUI views into a picture. The implementation may be very easy. You instantiate an occasion of ImageRenderer with a view for the conversion:
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let renderer = ImageRenderer(content material: theView) |
You may then entry the cgImage or uiImage property to retrieve the generated picture.
As all the time, I like to exhibit the utilization of an API with an instance. Earlier, we’ve constructed a line chart utilizing the brand new Charts framework. Let’s see the way to let customers save the chart as a picture within the picture album and share it utilizing ShareLink.
Revisit the Chart View
First, let’s revisit the code of the ChartView instance. We used the brand new API of the Charts framework to create a line chart and show the climate knowledge. Right here is the code snippet:
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var physique: some View {     VStack {         Chart {             ForEach(chartData, id: .metropolis) { collection in                 ForEach(collection.knowledge) { merchandise in                     LineMark(                         x: .worth(“Month”, merchandise.date),                         y: .worth(“Temp”, merchandise.temperature)                     )                 }                 .foregroundStyle(by: .worth(“Metropolis”, collection.metropolis))                 .image(by: .worth(“Metropolis”, collection.metropolis))             }         }         .chartXAxis {             AxisMarks(values: .stride(by: .month)) { worth in                 AxisGridLine()                 AxisValueLabel(format: .dateTime.month(.defaultDigits))              }         }         .chartPlotStyle { plotArea in             plotArea                 .background(.blue.opacity(0.1))         }         .chartYAxis {             AxisMarks(place: .main)         }         .body(width: 350, peak: 300)         .padding(.horizontal)      } } |
To make use of ImageRenderer, we first refactor this piece of code into a technique like this:
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personal func makeChartView() –> some View {     VStack {         Chart {             ForEach(chartData, id: .metropolis) { collection in                 ForEach(collection.knowledge) { merchandise in                     LineMark(                         x: .worth(“Month”, merchandise.date),                         y: .worth(“Temp”, merchandise.temperature)                     )                 }                 .foregroundStyle(by: .worth(“Metropolis”, collection.metropolis))                 .image(by: .worth(“Metropolis”, collection.metropolis))             }         }         .chartXAxis {             AxisMarks(values: .stride(by: .month)) { worth in                 AxisGridLine()                 AxisValueLabel(format: .dateTime.month(.defaultDigits))              }         }         .chartPlotStyle { plotArea in             plotArea                 .background(.blue.opacity(0.1))         }         .chartYAxis {             AxisMarks(place: .main)         }         .body(width: 350, peak: 300)          .padding(.horizontal)      } } |
Subsequent, we declare a variable to carry the view:
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var chartView = ChartView() |
Changing the View into an Picture utilizing ImageRenderer
Now we’re able to convert the chart view into a picture. We’ll add a button named Save to Pictures for saving the chart view picture within the picture album.
Let’s implement the button like this:
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var physique: some View {      VStack(spacing: 20) {         chartView          HStack {             Button {                 let renderer = ImageRenderer(content material: chartView)                  if let picture = renderer.uiImage {                     UIImageWriteToSavedPhotosAlbum(picture, nil, nil, nil)                 }             } label: {                 Label(“Save to Pictures”, systemImage: “picture”)             }             .buttonStyle(.borderedProminent)         }     }  } |
Within the closure of the button, we create an occasion of ImageRenderer with chartView and get the rendered picture by utilizing the uiImage property. Then we name UIImageWriteToSavedPhotosAlbum to save lots of the picture to the picture album.
Word: It is advisable add a key named Privateness – Picture Library Utilization Description within the data.plist earlier than the app can correctly save a picture to the built-in picture album.
Including a Share Button
Earlier, you realized the way to use ShareLink to current a share sheet for content material sharing. With ImageRenderer, you may simply construct a operate for customers to share the chart view.
For comfort objective, let’s refactor the code for picture rendering right into a separate methodology:
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@MainActor personal func generateSnapshot() –> UIImage { Â Â Â Â let renderer = ImageRenderer(content material: chartView) Â Â Â Â Â return renderer.uiImage ?? UIImage() } |
The generateSnapshot methodology converts the chartView into a picture.
Word: In case you are new to @MainActor, you may try this text.
With this helper methodology, we will create a ShareLink like this within the VStack view:
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ShareLink(merchandise: Picture(uiImage: generateSnapshot()), preview: SharePreview(“Climate Chart”, picture: Picture(uiImage: generateSnapshot()))) .buttonStyle(.borderedProminent) |
Now once you faucet the Share button, the app captures the road chart and allows you to share it as a picture.
Adjusting the Picture Scale
You might discover the decision of the rendered picture is a bit low. The ImageRenderer class has a property named scale so that you can modify the dimensions of the rendered picture. By default, its worth is about to 1.0. To generate a picture with a better decision, you may set it to 2.0 or 3.0. Alternatively, you may set the worth to the dimensions of the display screen:
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renderer.scale = UIScreen.major.scale |
Abstract
The ImageRenderer class has made it very straightforward to transform any SwiftUI views into a picture. In case your app helps iOS 16 or up, you should utilize this new API to create some handy options on your customers. Apart from rendering photographs, ImageRenderer additionally enables you to render a PDF doc. You may consult with the official documentation for additional particulars.
For charts, Apple additionally comes with a extra particular renderer known as ChartRenderer for exporting a chart as a picture. Later, we’ll additional look into this class.
Founding father of AppCoda. Writer of a number of iOS programming books together with Starting iOS Programming with Swift and Mastering SwiftUI. iOS App Developer and Blogger. Observe me at Fb, Twitter and Google+.
