Use image renderer

Author: jcavar

README.md

@@ -67,6 +67,8 @@ Snapshot audio tests are snapshot tested itself. Please find many examples in: [
 - [ ] Multi level comparison (first hash, then data, then image)
 - [ ] Use accelerate in downsampling
 - [x] Add file strategy
+- [ ] Use smaller images to not bloat the size of repo
+- [ ] Use sparklines
 
 ## Contributing
 

Sources/AudioSnapshotTesting/AudioSnapshotTesting.swift

@@ -72,8 +72,9 @@ public extension Snapshotting where Format == PlatformImage, Value == (AVAudioPC
     ///    - height: The height of the resulting image.
     ///    - strategy: The strategy to use when generating the waveform. Defaults to `.joinedLines`.
     ///    - mono: A boolean indicating whether to mix down to a mono signal before generating the waveform. Defaults to `true`.
+    @available(macOS 13.0, iOS 16.0, *)
     static func waveform(width: Int, height: Int, strategy: WaveformStrategy = .joinedLines, mono: Bool = true) -> Snapshotting {
-        Snapshotting<PlatformView, PlatformImage>.image(size: .init(width: width, height: height))
+        SimplySnapshotting<PlatformImage>.image()
             .pullback { buffer1, buffer2 in
                 let verticalPadding: CGFloat = 4
                 let waveformHeight = CGFloat(height) - (verticalPadding * 2)
@@ -95,7 +96,8 @@ public extension Snapshotting where Format == PlatformImage, Value == (AVAudioPC
                 }
                 .padding(.vertical, verticalPadding)
                 .background(Color.black)
-                return PlatformHostingView(rootView: waveform.environment(\.colorScheme, .light))
+
+                return renderViewToImage(waveform, width: width, height: height)
             }
     }
 }
@@ -108,8 +110,14 @@ public extension Snapshotting where Format == PlatformImage, Value == AVAudioPCM
     ///    - height: The height of the resulting image.
     ///    - strategy: The strategy to use when generating the waveform. Defaults to `.joinedLines`.
     ///    - mono: A boolean indicating whether to mix down to a mono signal before generating the waveform. Defaults to `true`.
-    static func waveform(width: Int, height: Int, strategy: WaveformStrategy = .joinedLines, mono: Bool = true) -> Snapshotting {
-        Snapshotting<PlatformView, PlatformImage>.image(size: .init(width: width, height: height))
+    @available(macOS 13.0, iOS 16.0, *)
+    static func waveform(
+        width: Int,
+        height: Int,
+        strategy: WaveformStrategy = .joinedLines,
+        mono: Bool = true
+    ) -> Snapshotting {
+        SimplySnapshotting<PlatformImage>.image()
             .pullback { buffer in
                 let verticalPadding: CGFloat = 4
                 let waveformHeight = CGFloat(height) - (verticalPadding * 2)
@@ -121,7 +129,8 @@ public extension Snapshotting where Format == PlatformImage, Value == AVAudioPCM
                 )
                 .padding(.vertical, verticalPadding)
                 .background(Color.black)
-                return PlatformHostingView(rootView: waveform.environment(\.colorScheme, .light))
+
+                return renderViewToImage(waveform, width: width, height: height)
             }
     }
 
@@ -138,14 +147,14 @@ public extension Snapshotting where Format == PlatformImage, Value == AVAudioPCM
         window: [Float]? = nil,
         threshold: Float = 0.005
     ) -> Snapshotting {
-        Snapshotting<PlatformView, PlatformImage>.image(size: .init(width: width, height: height))
+        SimplySnapshotting<PlatformImage>.image()
             .pullback { buffer in
                 let effectiveWindow = window ?? createHannWindow(size: Int(buffer.frameLength))
                 let data = buffer
                     .spectrum(window: effectiveWindow)
                     .filter { $0.amplitude > threshold }
                 let spectrum = SpectrumView(data: data, height: CGFloat(height))
-                return PlatformHostingView(rootView: spectrum.environment(\.colorScheme, .light))
+                return renderViewToImage(spectrum, width: width, height: height)
             }
     }
 
@@ -165,7 +174,7 @@ public extension Snapshotting where Format == PlatformImage, Value == AVAudioPCM
         imageWidth: Int = 1000
     ) -> Snapshotting {
         let height = frequencyCount
-        return Snapshotting<PlatformView, PlatformImage>.image(size: .init(width: imageWidth, height: height))
+        return SimplySnapshotting<PlatformImage>.image()
             .pullback { buffer in
                 let fftSize = frequencyCount * 2
                 let lastBucketStart = Int(buffer.frameLength) - fftSize
@@ -187,11 +196,32 @@ public extension Snapshotting where Format == PlatformImage, Value == AVAudioPCM
                 let duration = Double(buffer.frameLength) / buffer.format.sampleRate
 
                 let spectrogram = SpectrogramView(data: data, width: width, height: height, maxFrequency: maxFrequency, duration: duration)
-                return PlatformHostingView(rootView: spectrogram.environment(\.colorScheme, .light))
+                return renderViewToImage(spectrogram, width: imageWidth, height: height)
             }
     }
 }
 
+/// Renders a SwiftUI view to a platform image using ImageRenderer
+/// - Parameters:
+///   - view: The SwiftUI view to render
+///   - width: The width of the resulting image
+///   - height: The height of the resulting image
+/// - Returns: A platform-specific image (NSImage on macOS, UIImage on iOS)
+@available(iOS 16.0, macOS 13.0, *)
+@MainActor
+private func renderViewToImage<Content: View>(_ view: Content, width: Int, height: Int) -> PlatformImage {
+    let renderer = ImageRenderer(
+        content: view.environment(\.colorScheme, .light)
+    )
+    renderer.proposedSize = .init(width: CGFloat(width), height: CGFloat(height))
+    renderer.scale = 2
+    #if os(iOS)
+    return renderer.uiImage!
+    #else
+    return renderer.nsImage!
+    #endif
+}
+
 /// Creates a normalized Hann window of the specified size
 /// - Parameter size: The number of samples in the window
 /// - Returns: An array of Float values representing the Hann window function

Sources/AudioSnapshotTesting/CGImageExtensions.swift

@@ -7,11 +7,9 @@ extension CGImage {
         let rgbImageFormat = vImage_CGImageFormat(
             bitsPerComponent: 32,
             bitsPerPixel: 32 * 3,
-            colorSpace: CGColorSpaceCreateDeviceRGB(),
-            bitmapInfo: CGBitmapInfo(
-                rawValue: kCGBitmapByteOrder32Host.rawValue |
-                CGBitmapInfo.floatComponents.rawValue |
-                CGImageAlphaInfo.none.rawValue))!
+            colorSpace: CGColorSpace(name: CGColorSpace.sRGB)!,
+            bitmapInfo: CGBitmapInfo.floatComponents
+        )!
 
         /// RGB vImage buffer that contains a vertical representation of the audio spectrogram.
         let redBuffer = vImage.PixelBuffer<vImage.PlanarF>(width: height, height: width)
@@ -42,29 +40,29 @@ extension CGImage {
     }
 }
 
+// Lookup table resolution: 32 entries provides good color accuracy while keeping memory usage low
+// Higher values (64, 128) would provide smoother gradients but increase memory and initialization time
+// Lower values (16, 8) would be faster but produce visible banding in spectrograms
+let entriesPerChannel = UInt8(32)
+
+
 /// Returns the RGB values from a blue -> red -> green color map for a specified value.
 ///
 /// Values near zero return dark blue, `0.5` returns red, and `1.0` returns full-brightness green.
 @available(macOS 13, iOS 16, *)
 nonisolated(unsafe) var multidimensionalLookupTable: vImage.MultidimensionalLookupTable = {
-    // Lookup table resolution: 32 entries provides good color accuracy while keeping memory usage low
-    // Higher values (64, 128) would provide smoother gradients but increase memory and initialization time
-    // Lower values (16, 8) would be faster but produce visible banding in spectrograms
-    let entriesPerChannel = UInt8(32)
     let srcChannelCount = 1
     let destChannelCount = 3
 
     let lookupTableElementCount = Int(pow(Float(entriesPerChannel), Float(srcChannelCount))) * Int(destChannelCount)
 
-    let tableData = [UInt16](unsafeUninitializedCapacity: lookupTableElementCount) {
-        buffer,
-        count in
+    let tableData = [UInt16](unsafeUninitializedCapacity: lookupTableElementCount) { buffer, count in
         /// Supply the samples in the range `0...65535`. The transform function
         /// interpolates these to the range `0...1`.
         let multiplier = CGFloat(UInt16.max)
         var bufferIndex = 0
 
-        for gray in ( 0 ..< entriesPerChannel) {
+        for gray in 0 ..< entriesPerChannel {
             /// Create normalized red, green, and blue values in the range `0...1`.
             let normalizedValue = CGFloat(gray) / CGFloat(entriesPerChannel - 1)
 
@@ -85,11 +83,11 @@ nonisolated(unsafe) var multidimensionalLookupTable: vImage.MultidimensionalLook
 
             color.getRed(&r, green: &g, blue: &b, alpha: nil)
 
-            buffer[ bufferIndex ] = UInt16(g * multiplier)
+            buffer[bufferIndex] = UInt16(g * multiplier)
             bufferIndex += 1
-            buffer[ bufferIndex ] = UInt16(r * multiplier)
+            buffer[bufferIndex] = UInt16(r * multiplier)
             bufferIndex += 1
-            buffer[ bufferIndex ] = UInt16(b * multiplier)
+            buffer[bufferIndex] = UInt16(b * multiplier)
             bufferIndex += 1
         }
         count = lookupTableElementCount

Sources/AudioSnapshotTesting/SpectrogramView.swift

@@ -39,6 +39,10 @@ struct SpectrogramView: View {
     }
 
     var body: some View {
+        image
+            .resizable()
+            .padding(.vertical, SpectrogramLayout.verticalPadding)
+        /*
         VStack(spacing: 0) {
             HStack(spacing: SpectrogramLayout.labelSpacing) {
                 FrequencyAxisView(maxFrequency: maxFrequency)
@@ -53,6 +57,7 @@ struct SpectrogramView: View {
                     .padding(.horizontal, SpectrogramLayout.horizontalPadding)
             }
         }
+         */
     }
 }
 
@@ -123,7 +128,7 @@ private struct FrequencyLabel: View {
 
     var body: some View {
         Text(Self.frequencyFormatter.string(from: NSNumber(value: frequency)) ?? "\(frequency)")
-            .font(.caption)
+            .font(.system(size: 10, weight: .regular, design: .monospaced))
             .foregroundColor(.secondary)
             .frame(height: SpectrogramLayout.frequencyLabelHeight)
     }
@@ -183,7 +188,7 @@ private struct TimeLabel: View {
 
     var body: some View {
         Text(formatTime(time, totalDuration: duration))
-            .font(.caption)
+            .font(.system(size: 10, weight: .regular, design: .monospaced))
             .foregroundColor(.secondary)
     }
 

Sources/AudioSnapshotTesting/SpectrumView.swift

@@ -17,21 +17,31 @@ struct SpectrumView: View {
         .chartYAxis {
             AxisMarks(position: .leading) { _ in
                 AxisValueLabel()
+                    .font(.system(size: 10, weight: .regular, design: .monospaced))
                     .foregroundStyle(.white)
                 AxisGridLine()
                     .foregroundStyle(.white.opacity(0.3))
             }
         }
-        .chartYAxisLabel(position: .leading) { Text("Amplitude").foregroundStyle(.white) }
+        .chartYAxisLabel(position: .leading) { 
+            Text("Amplitude")
+                .font(.system(size: 12, weight: .regular, design: .monospaced))
+                .foregroundStyle(.white) 
+        }
         .chartXAxis {
             AxisMarks(preset: .aligned, values: xAxisValues) { _ in
                 AxisValueLabel()
+                    .font(.system(size: 10, weight: .regular, design: .monospaced))
                     .foregroundStyle(.white)
                 AxisGridLine()
                     .foregroundStyle(.white.opacity(0.3))
             }
         }
-        .chartXAxisLabel(position: .bottom) { Text("Frequency (Hz)").foregroundStyle(.white) }
+        .chartXAxisLabel(position: .bottom) { 
+            Text("Frequency (Hz)")
+                .font(.system(size: 12, weight: .regular, design: .monospaced))
+                .foregroundStyle(.white) 
+        }
         .padding(16)
         .frame(height: height)
         .background(Color.black)

Tests/AudioSnapshotTestingTests/AudioSnapshotTestingTests.swift

@@ -2,21 +2,21 @@ import Testing
 import AVFAudio
 @testable import AudioSnapshotTesting
 
+@available(iOS 16.0, *)
 @Test(
     .snapshots(record: false, diffTool: .ksdiff),
     arguments: ["sine", "triangle", "square", "sawtooth", "brown", "pink", "white"]
 )
 @MainActor
 func fileWaveform(wave: String) async throws {
-    // TODO: account for retina
-
     assertSnapshot(
         of: try AVAudioPCMBuffer.read(wave: wave),
         as: .waveform(width: 3000, height: 800),
         named: wave
     )
 }
 
+@available(iOS 16.0, *)
 @Test(.snapshots(record: false, diffTool: .ksdiff))
 @MainActor
 func fileWaveformMetronome() async throws {
@@ -27,6 +27,7 @@ func fileWaveformMetronome() async throws {
     )
 }
 
+@available(iOS 16.0, *)
 @Test(.snapshots(record: false, diffTool: .ksdiff))
 @MainActor
 func stereoFileWaveform() async throws {
@@ -36,6 +37,7 @@ func stereoFileWaveform() async throws {
     )
 }
 
+@available(iOS 16, *)
 @Test(.snapshots(record: false, diffTool: .ksdiff))
 @MainActor
 func fileWaveformOverlay() async throws {
@@ -102,28 +104,42 @@ func spectrumSynthesised() async throws {
 
 @available(iOS 16, *)
 @Test(
-    "Generates color spectrum spectrogram",
-    .snapshots(record: false, diffTool: .ksdiff)
+    .snapshots(record: true, diffTool: .ksdiff)
 )
 @MainActor
 func spectrogramColors() async throws {
-    let frequencyCount = 1024
+    let frequencyCount = 32
     let signal = synthesizeSignal(
         frequencyAmplitudePairs: (0..<frequencyCount).map { (Float($0), Float($0) / Float(frequencyCount)) },
-        count: 2048
+        count: frequencyCount * 2
     )
-    let buffer = createBuffer(from: signal + signal + signal + signal)
+    let buffer = createBuffer(from: signal)
 
+    #if os(macOS)
     assertSnapshot(
         of: buffer,
         as: .spectrogram(
             hopSize: 128,
             frequencyCount: frequencyCount,
             window: [Float](repeating: 1, count: 2048),
             amplitudeScale: .linear,
-            imageWidth: 200
-        )
+            imageWidth: 1
+        ),
+        named: "macOS"
+    )
+    #else
+    assertSnapshot(
+        of: buffer,
+        as: .spectrogram(
+            hopSize: 128,
+            frequencyCount: frequencyCount,
+            window: [Float](repeating: 1, count: 2048),
+            amplitudeScale: .linear,
+            imageWidth: 1
+        ),
+        named: "iOS"
     )
+    #endif
 }
 
 @available(iOS 16, *)