ImageRenderer is one other new API for SwiftUI that comes with iOS 16. It permits you to simply convert any SwiftUI views into a picture. The implementation could 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’ll be able to then entry the cgImage or uiImage property to retrieve the generated picture.
As all the time, I like to show the utilization of an API with an instance. Earlier, we’ve constructed a line chart utilizing the brand new Charts framework. Let’s see methods 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) sequence in                 ForEach(sequence.knowledge) merchandise in                     LineMark(                         x: .worth(“Month”, merchandise.date),                         y: .worth(“Temp”, merchandise.temperature)                     )                                 .foregroundStyle(by: .worth(“Metropolis”, sequence.metropolis))                 .image(by: .worth(“Metropolis”, sequence.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, top: 300)         .padding(.horizontal)      } |
To make use of ImageRenderer, we first refactor this piece of code right into a separate view like this:
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struct ChartView: View {     let chartData = [ (city: “Hong Kong”, data: hkWeatherData),                       (city: “London”, data: londonWeatherData),                       (city: “Taipei”, data: taipeiWeatherData)     ]         var physique: some View {         VStack                         Chart                 ForEach(chartData, id: .metropolis) sequence in                     ForEach(sequence.knowledge) merchandise in                         LineMark(                             x: .worth(“Month”, merchandise.date),                             y: .worth(“Temp”, merchandise.temperature)                         )                                         .foregroundStyle(by: .worth(“Metropolis”, sequence.metropolis))                     .image(by: .worth(“Metropolis”, sequence.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, top: 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 Photographs 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 Photographs”, 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.
Observe: It’s worthwhile to add a key named Privateness – Photograph 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 how to use ShareLink to present a share sheet for content material sharing. With ImageRenderer, you’ll be able to simply construct a operate for customers to share the chart view.
For comfort goal, let’s refactor the code for picture rendering right into a separate technique:
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@MainActor personal func generateSnapshot() –> UIImage     let renderer = ImageRenderer(content material: chartView)      return renderer.uiImage ?? UIImage()
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The generateSnapshot technique converts the chartView into a picture.
Observe: In case you are new to @MainActor, you’ll be able to check out this article.
With this helper technique, 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 if 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 could discover the decision of the rendered picture is a bit low. The ImageRenderer class has a property named scale so that you can alter the dimensions of the rendered picture. By default, its worth is about to 1.0. To generate a picture with a better decision, you’ll be able to set it to 2.0 or 3.0. Alternatively, you’ll be able to set the worth to the dimensions of the display screen:
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renderer.scale = UIScreen.important.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 use this new API to create some handy options on your customers. Apart from rendering pictures, ImageRenderer additionally enables you to render a PDF doc. You’ll be able to check with the official documentation for additional particulars.
For charts, Apple additionally comes with a extra particular renderer referred to 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+.
