ImageRenderer is one other new API for SwiftUI that comes with iOS 16. It means that you can 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 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 right way to let customers save the chart as a picture within the photograph 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 information. Right here is the code snippet:
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var physique: some View { VStack { Chart { ForEach(chartData, id: .metropolis) { sequence in ForEach(sequence.information) { 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, peak: 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.information) { 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, peak: 300) .padding(.horizontal)
} } }
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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 Images for saving the chart view picture within the photograph 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 Images”, systemImage: “photograph”) } .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 photograph album.
Notice: It’s essential add a key named Privateness – Picture Library Utilization Description within the information.plist earlier than the app can correctly save a picture to the built-in photograph album.
Including a Share Button
Earlier, you discovered the right way to use ShareLink to current 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 objective, let’s refactor the code for picture rendering right into a separate methodology:
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@MainActor personal func generateSnapshot() –> UIImage { let renderer = ImageRenderer(content material: chartView)
return renderer.uiImage ?? UIImage() } |
The generateSnapshot methodology converts the chartView into a picture.
Notice: If you’re new to @MainActor, you’ll be able to take a look at 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 whenever 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 regulate the size of the rendered picture. By default, its worth is ready 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 size of the display:
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renderer.scale = UIScreen.primary.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 to your customers. Aside from rendering photographs, ImageRenderer additionally enables you to render a PDF doc. You’ll be able to 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 are going to additional look into this class.
Founding father of AppCoda. Creator 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+.
