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 may then entry the cgImage or uiImage property to retrieve the generated picture.
As all the time, I like to display the utilization of an API with an instance. Earlier, we’ve constructed a line chart utilizing the brand new Charts framework. Let’s see 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 information. Right here is the code snippet:
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var physique: some View { VStack { Chart { ForEach(chartData, id: .metropolis) { collection in ForEach(collection.information) { 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, 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) { collection in ForEach(collection.information) { 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, top: 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 are going to 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 avoid wasting the picture to the picture album.
Be aware: You must 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 discovered use ShareLink to current a share sheet for content material sharing. With ImageRenderer, you possibly can simply construct a perform for customers to share the chart view.
For comfort goal, 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.
Be aware: If you’re new to @MainActor, you possibly can 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
Chances are you’ll 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 the next decision, you possibly can set it to 2.0 or 3.0. Alternatively, you possibly can set the worth to the dimensions of the display screen:
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renderer.scale = UIScreen.most 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 need to use this new API to create some handy options in your customers. Aside from rendering photographs, ImageRenderer additionally permits you to render a PDF doc. You may confer 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+.
