Various improvements

submodules/StickerResources/Sources/StickerResources.swift

@@ -8,6 +8,7 @@ import MediaResources
 import Tuples
 import ImageBlur
 import FastBlur
+import Accelerate
 
 public func imageFromAJpeg(data: Data) -> (UIImage, UIImage)? {
     if let (colorData, alphaData) = data.withUnsafeBytes({ bytes -> (Data, Data)? in
@@ -660,3 +661,100 @@ public func preloadedStickerPackThumbnail(account: Account, info: StickerPackCol
     
     return .single(true)
 }
+
+public func getAverageColor(image: UIImage) -> UIColor? {
+    let blurredWidth = 16
+    let blurredHeight = 16
+    let blurredBytesPerRow = blurredWidth * 4
+    guard let context = DrawingContext(size: CGSize(width: CGFloat(blurredWidth), height: CGFloat(blurredHeight)), scale: 1.0, opaque: true, bytesPerRow: blurredBytesPerRow) else {
+        return nil
+    }
+    
+    let size = CGSize(width: CGFloat(blurredWidth), height: CGFloat(blurredHeight))
+    
+    if let cgImage = image.cgImage {
+        context.withFlippedContext { c in
+            c.setFillColor(UIColor.white.cgColor)
+            c.fill(CGRect(origin: CGPoint(), size: size))
+            c.draw(cgImage, in: CGRect(origin: CGPoint(x: -size.width / 2.0, y: -size.height / 2.0), size: CGSize(width: size.width * 1.8, height: size.height * 1.8)))
+        }
+    }
+        
+    var destinationBuffer = vImage_Buffer()
+    destinationBuffer.width = UInt(blurredWidth)
+    destinationBuffer.height = UInt(blurredHeight)
+    destinationBuffer.data = context.bytes
+    destinationBuffer.rowBytes = context.bytesPerRow
+    
+    vImageBoxConvolve_ARGB8888(&destinationBuffer,
+                               &destinationBuffer,
+                               nil,
+                               0, 0,
+                               UInt32(15),
+                               UInt32(15),
+                               nil,
+                               vImage_Flags(kvImageTruncateKernel))
+    
+    let divisor: Int32 = 0x1000
+
+    let rwgt: CGFloat = 0.3086
+    let gwgt: CGFloat = 0.6094
+    let bwgt: CGFloat = 0.0820
+
+    let adjustSaturation: CGFloat = 1.7
+
+    let a = (1.0 - adjustSaturation) * rwgt + adjustSaturation
+    let b = (1.0 - adjustSaturation) * rwgt
+    let c = (1.0 - adjustSaturation) * rwgt
+    let d = (1.0 - adjustSaturation) * gwgt
+    let e = (1.0 - adjustSaturation) * gwgt + adjustSaturation
+    let f = (1.0 - adjustSaturation) * gwgt
+    let g = (1.0 - adjustSaturation) * bwgt
+    let h = (1.0 - adjustSaturation) * bwgt
+    let i = (1.0 - adjustSaturation) * bwgt + adjustSaturation
+
+    let satMatrix: [CGFloat] = [
+        a, b, c, 0,
+        d, e, f, 0,
+        g, h, i, 0,
+        0, 0, 0, 1
+    ]
+
+    var matrix: [Int16] = satMatrix.map { value in
+        return Int16(value * CGFloat(divisor))
+    }
+
+    vImageMatrixMultiply_ARGB8888(&destinationBuffer, &destinationBuffer, &matrix, divisor, nil, nil, vImage_Flags(kvImageDoNotTile))
+    
+    context.withFlippedContext { c in
+        c.setFillColor(UIColor.white.withMultipliedAlpha(0.1).cgColor)
+        c.fill(CGRect(origin: CGPoint(), size: size))
+    }
+    
+    var sumR: UInt64 = 0
+    var sumG: UInt64 = 0
+    var sumB: UInt64 = 0
+    var sumA: UInt64 = 0
+    
+    for y in 0 ..< blurredHeight {
+        let row = context.bytes.assumingMemoryBound(to: UInt8.self).advanced(by: y * blurredBytesPerRow)
+        for x in 0 ..< blurredWidth {
+            let pixel = row.advanced(by: x * 4)
+            sumB += UInt64(pixel.advanced(by: 0).pointee)
+            sumG += UInt64(pixel.advanced(by: 1).pointee)
+            sumR += UInt64(pixel.advanced(by: 2).pointee)
+            sumA += UInt64(pixel.advanced(by: 3).pointee)
+        }
+    }
+    sumR /= UInt64(blurredWidth * blurredHeight)
+    sumG /= UInt64(blurredWidth * blurredHeight)
+    sumB /= UInt64(blurredWidth * blurredHeight)
+    sumA /= UInt64(blurredWidth * blurredHeight)
+    sumA = 255
+    
+    var color = UIColor(red: CGFloat(sumR) / 255.0, green: CGFloat(sumG) / 255.0, blue: CGFloat(sumB) / 255.0, alpha: CGFloat(sumA) / 255.0)
+    if color.lightness > 0.8 {
+        color = color.withMultipliedBrightnessBy(0.8)
+    }
+    return color
+}