Image2Image Encoder

Encoder

swift/StableDiffusion/pipeline/AlphasCumprodCalculation.swift

@@ -0,0 +1,29 @@
+// For licensing see accompanying LICENSE.md file.
+// Copyright (C) 2022 Apple Inc. All Rights Reserved.
+
+import Foundation
+
+public struct AlphasCumprodCalculation {
+    public var sqrtAlphasCumprod: Float
+    public var sqrtOneMinusAlphasCumprod: Float
+    
+    public init(
+        sqrtAlphasCumprod: Float,
+        sqrtOneMinusAlphasCumprod: Float
+    ) {
+        self.sqrtAlphasCumprod = sqrtAlphasCumprod
+        self.sqrtOneMinusAlphasCumprod = sqrtOneMinusAlphasCumprod
+    }
+    
+    public init(
+        alphasCumprod: [Float],
+        timesteps: Int = 1_000,
+        steps: Int,
+        strength: Float
+    ) {
+        let tEnc = Int(strength * Float(steps))
+        let initTimestep = timesteps - timesteps / steps * (steps - tEnc) + 1
+        self.sqrtAlphasCumprod = alphasCumprod[initTimestep].squareRoot()
+        self.sqrtOneMinusAlphasCumprod = (1 - alphasCumprod[initTimestep]).squareRoot()
+    }
+}

swift/StableDiffusion/pipeline/CGImage+vImage.swift

@@ -0,0 +1,120 @@
+// For licensing see accompanying LICENSE.md file.
+// Copyright (C) 2022 Apple Inc. All Rights Reserved.
+
+import Foundation
+import Accelerate
+import CoreML
+
+@available(iOS 16.0, macOS 13.0, *)
+extension CGImage {
+    
+    typealias PixelBufferPFx1 = vImage.PixelBuffer<vImage.PlanarF>
+    typealias PixelBufferP8x3 = vImage.PixelBuffer<vImage.Planar8x3>
+    typealias PixelBufferIFx3 = vImage.PixelBuffer<vImage.InterleavedFx3>
+    typealias PixelBufferI8x3 = vImage.PixelBuffer<vImage.Interleaved8x3>
+    
+    public enum ShapedArrayError: String, Swift.Error {
+        case wrongNumberOfChannels
+        case incorrectFormatsConvertingToShapedArray
+        case vImageConverterNotInitialized
+    }
+    
+    public static func fromShapedArray(_ array: MLShapedArray<Float32>) throws -> CGImage {
+        
+        // array is [N,C,H,W], where C==3
+        let channelCount = array.shape[1]
+        guard channelCount == 3 else {
+            throw ShapedArrayError.wrongNumberOfChannels
+        }
+        
+        let height = array.shape[2]
+        let width = array.shape[3]
+
+        // Normalize each channel into a float between 0 and 1.0
+        let floatChannels = (0..<channelCount).map { i in
+
+            // Normalized channel output
+            let cOut = PixelBufferPFx1(width: width, height:height)
+
+            // Reference this channel in the array and normalize
+            array[0][i].withUnsafeShapedBufferPointer { ptr, _, strides in
+                let cIn = PixelBufferPFx1(data: .init(mutating: ptr.baseAddress!),
+                                          width: width, height: height,
+                                          byteCountPerRow: strides[0]*4)
+                // Map [-1.0 1.0] -> [0.0 1.0]
+                cIn.multiply(by: 0.5, preBias: 1.0, postBias: 0.0, destination: cOut)
+            }
+            return cOut
+        }
+
+        // Convert to interleaved and then to UInt8
+        let floatImage = PixelBufferIFx3(planarBuffers: floatChannels)
+        let uint8Image = PixelBufferI8x3(width: width, height: height)
+        floatImage.convert(to:uint8Image) // maps [0.0 1.0] -> [0 255] and clips
+
+        // Convert to uint8x3 to RGB CGImage (no alpha)
+        let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.none.rawValue)
+        let cgImage = uint8Image.makeCGImage(cgImageFormat:
+                .init(bitsPerComponent: 8,
+                      bitsPerPixel: 3*8,
+                      colorSpace: CGColorSpaceCreateDeviceRGB(),
+                      bitmapInfo: bitmapInfo)!)!
+
+        return cgImage
+    }
+    
+    public var plannerRGBShapedArray: MLShapedArray<Float32> {
+        get throws {
+            guard
+                var sourceFormat = vImage_CGImageFormat(cgImage: self),
+                var mediumFormat = vImage_CGImageFormat(
+                    bitsPerComponent: 8 * MemoryLayout<UInt8>.size,
+                    bitsPerPixel: 8 * MemoryLayout<UInt8>.size * 4,
+                    colorSpace: CGColorSpaceCreateDeviceRGB(),
+                    bitmapInfo: CGBitmapInfo(rawValue: CGImageAlphaInfo.first.rawValue)),
+                let width = vImagePixelCount(exactly: self.width),
+                let height = vImagePixelCount(exactly: self.height)
+            else {
+                throw ShapedArrayError.incorrectFormatsConvertingToShapedArray
+            }
+            
+            var sourceImageBuffer = try vImage_Buffer(cgImage: self)
+            
+            var mediumDesination = try vImage_Buffer(width: Int(width), height: Int(height), bitsPerPixel: mediumFormat.bitsPerPixel)
+            
+            let converter = vImageConverter_CreateWithCGImageFormat(
+                &sourceFormat,
+                &mediumFormat,
+                nil,
+                vImage_Flags(kvImagePrintDiagnosticsToConsole),
+                nil)
+            
+            guard let converter = converter?.takeRetainedValue() else {
+                throw ShapedArrayError.vImageConverterNotInitialized
+            }
+            
+            vImageConvert_AnyToAny(converter, &sourceImageBuffer, &mediumDesination, nil, vImage_Flags(kvImagePrintDiagnosticsToConsole))
+            
+            var destinationA = try vImage_Buffer(width: Int(width), height: Int(height), bitsPerPixel: 8 * UInt32(MemoryLayout<Float>.size))
+            var destinationR = try vImage_Buffer(width: Int(width), height: Int(height), bitsPerPixel: 8 * UInt32(MemoryLayout<Float>.size))
+            var destinationG = try vImage_Buffer(width: Int(width), height: Int(height), bitsPerPixel: 8 * UInt32(MemoryLayout<Float>.size))
+            var destinationB = try vImage_Buffer(width: Int(width), height: Int(height), bitsPerPixel: 8 * UInt32(MemoryLayout<Float>.size))
+            
+            var minFloat: [Float] = [-1.0, -1.0, -1.0, -1.0]
+            var maxFloat: [Float] = [1.0, 1.0, 1.0, 1.0]
+            
+            vImageConvert_ARGB8888toPlanarF(&mediumDesination, &destinationA, &destinationR, &destinationG, &destinationB, &maxFloat, &minFloat, .zero)
+           
+            let redData = Data(bytes: destinationR.data, count: Int(width) * Int(height) * MemoryLayout<Float>.size)
+            let greenData = Data(bytes: destinationG.data, count: Int(width) * Int(height) * MemoryLayout<Float>.size)
+            let blueData = Data(bytes: destinationB.data, count: Int(width) * Int(height) * MemoryLayout<Float>.size)
+            
+            let imageData = redData + greenData + blueData
+
+            let shapedArray = MLShapedArray<Float32>(data: imageData, shape: [1, 3, 512, 512])
+            
+            return shapedArray
+        }
+    }
+}
+

swift/StableDiffusion/pipeline/Decoder.swift

@@ -3,7 +3,6 @@
 
 import Foundation
 import CoreML
-import Accelerate
 
 /// A decoder model which produces RGB images from latent samples
 @available(iOS 16.2, macOS 13.1, *)
@@ -57,12 +56,11 @@ public struct Decoder: ResourceManaging {
         }
 
         // Transform the outputs to CGImages
-        let images: [CGImage] = (0..<results.count).map { i in
+        let images: [CGImage] = try (0..<results.count).map { i in
             let result = results.features(at: i)
             let outputName = result.featureNames.first!
             let output = result.featureValue(for: outputName)!.multiArrayValue!
-
+            return try CGImage.fromShapedArray(MLShapedArray<Float32>(output))
-            return toRGBCGImage(MLShapedArray<Float32>(output))
         }
 
         return images
@@ -74,50 +72,4 @@ public struct Decoder: ResourceManaging {
         }
     }
 
-    typealias PixelBufferPFx1 = vImage.PixelBuffer<vImage.PlanarF>
-    typealias PixelBufferP8x3 = vImage.PixelBuffer<vImage.Planar8x3>
-    typealias PixelBufferIFx3 = vImage.PixelBuffer<vImage.InterleavedFx3>
-    typealias PixelBufferI8x3 = vImage.PixelBuffer<vImage.Interleaved8x3>
-
-    func toRGBCGImage(_ array: MLShapedArray<Float32>) -> CGImage {
-
-        // array is [N,C,H,W], where C==3
-        let channelCount = array.shape[1]
-        assert(channelCount == 3,
-               "Decoding model output has \(channelCount) channels, expected 3")
-        let height = array.shape[2]
-        let width = array.shape[3]
-
-        // Normalize each channel into a float between 0 and 1.0
-        let floatChannels = (0..<channelCount).map { i in
-
-            // Normalized channel output
-            let cOut = PixelBufferPFx1(width: width, height:height)
-
-            // Reference this channel in the array and normalize
-            array[0][i].withUnsafeShapedBufferPointer { ptr, _, strides in
-                let cIn = PixelBufferPFx1(data: .init(mutating: ptr.baseAddress!),
-                                          width: width, height: height,
-                                          byteCountPerRow: strides[0]*4)
-                // Map [-1.0 1.0] -> [0.0 1.0]
-                cIn.multiply(by: 0.5, preBias: 1.0, postBias: 0.0, destination: cOut)
-            }
-            return cOut
-        }
-
-        // Convert to interleaved and then to UInt8
-        let floatImage = PixelBufferIFx3(planarBuffers: floatChannels)
-        let uint8Image = PixelBufferI8x3(width: width, height: height)
-        floatImage.convert(to:uint8Image) // maps [0.0 1.0] -> [0 255] and clips
-
-        // Convert to uint8x3 to RGB CGImage (no alpha)
-        let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.none.rawValue)
-        let cgImage = uint8Image.makeCGImage(cgImageFormat:
-                .init(bitsPerComponent: 8,
-                      bitsPerPixel: 3*8,
-                      colorSpace: CGColorSpaceCreateDeviceRGB(),
-                      bitmapInfo: bitmapInfo)!)!
-
-        return cgImage
-    }
 }

swift/StableDiffusion/pipeline/Encoder.swift

@@ -0,0 +1,80 @@
+// For licensing see accompanying LICENSE.md file.
+// Copyright (C) 2022 Apple Inc. All Rights Reserved.
+
+import Foundation
+import CoreML
+
+@available(iOS 16.0, macOS 13.0, *)
+/// Encoder, currently supports image2image
+public struct Encoder {
+    
+    public enum Error: String, Swift.Error {
+        case latentOutputNotValid
+        case batchLatentOutputEmpty
+    }
+    
+    /// VAE encoder model + post math and adding noise from schedular
+    var model: MLModel
+    
+    /// Create decoder from Core ML model
+    ///
+    /// - Parameters
+    ///     - model: Core ML model for VAE decoder
+    public init(model: MLModel) {
+        self.model = model
+    }
+    
+    /// Prediction queue
+    let queue = DispatchQueue(label: "encoder.predict")
+
+    /// Batch encode latent samples into images
+    /// - Parameters:
+    ///   - image: image used for image2image
+    ///   - diagonalNoise: random noise for `DiagonalGaussianDistribution` operation
+    ///   - noise: random noise for initial latent space based on strength argument
+    ///   - alphasCumprodStep: calculations using the scheduler traditionally calculated in the pipeline in pyTorch Diffusers library.
+    /// - Returns: The encoded latent space as MLShapedArray
+    public func encode(
+        image:  CGImage,
+        diagonalNoise: MLShapedArray<Float32>,
+        noise: MLShapedArray<Float32>,
+        alphasCumprodStep: AlphasCumprodCalculation
+    ) throws -> MLShapedArray<Float32> {
+        let sample = try image.plannerRGBShapedArray
+        let sqrtAlphasCumprod = MLShapedArray(scalars: [alphasCumprodStep.sqrtAlphasCumprod], shape: [1, 1])
+        let sqrtOneMinusAlphasCumprod = MLShapedArray(scalars: [alphasCumprodStep.sqrtOneMinusAlphasCumprod], shape: [1, 1])
+        
+        let dict: [String: Any] = [
+            "sample": MLMultiArray(sample),
+            "diagonalNoise": MLMultiArray(diagonalNoise),
+            "noise": MLMultiArray(noise),
+            "sqrtAlphasCumprod": MLMultiArray(sqrtAlphasCumprod),
+            "sqrtOneMinusAlphasCumprod": MLMultiArray(sqrtOneMinusAlphasCumprod),
+        ]
+        let featureProvider = try MLDictionaryFeatureProvider(dictionary: dict)
+        
+        let batch = MLArrayBatchProvider(array: [featureProvider])
+
+        // Batch predict with model
+        let results = try queue.sync { try model.predictions(fromBatch: batch) }
+        
+        let batchLatents: [MLShapedArray<Float32>] = try (0..<results.count).compactMap { i in
+            let result = results.features(at: i)
+            guard
+                let outputName = result.featureNames.first,
+                let output = result.featureValue(for: outputName)?.multiArrayValue
+            else {
+                throw Error.latentOutputNotValid
+            }
+            print("output.shape: \(output.shape)")
+            return MLShapedArray(output)
+        }
+        
+        guard let latents = batchLatents.first else {
+            throw Error.batchLatentOutputEmpty
+        }
+        
+        return latents
+    }
+    
+}