CGImage.resizedImage was broken for grayscale images

bitsPerComponent and pixel were hardcoded to 8/32, and colorSpace was empty. Works fine for RGB and ARGB but not for e.g. grayscale. Instead, we now pull this info from the CGImage we're passing anyway.

This fixes the test `testResizeGrayscaleImage` and therefore fixes #30.

CoreTootin/Extensions/CGImage+Additions.swift

@@ -17,8 +17,8 @@
 //  GNU General Public License for more details.
 //
 
-import Foundation
 import Accelerate
+import Foundation
 
 public extension CGImage
 {
@@ -29,27 +29,28 @@ public extension CGImage
 
 	func resizedImage(newHeight: CGFloat, scale: CGFloat = 1.0) -> CGImage?
 	{
-		let newWidth = (newHeight/CGFloat(height)) * CGFloat(width)
-		return resizedImage(newSize: CGSize(width: newWidth, height: newHeight), scale: scale)
+		let newWidth = (newHeight / CGFloat(height)) * CGFloat(width)
+		return self.resizedImage(newSize: CGSize(width: newWidth, height: newHeight), scale: scale)
 	}
 
 	func resizedImage(newSize: CGSize, scale: CGFloat = 1.0) -> CGImage?
 	{
-		var format = vImage_CGImageFormat(bitsPerComponent: 8,
-										  bitsPerPixel: 32,
-										  colorSpace: nil,
-										  bitmapInfo: bitmapInfo,
-										  version: 0, decode: nil, renderingIntent: .defaultIntent)
+		var format = vImage_CGImageFormat(bitsPerComponent: UInt32(self.bitsPerComponent),
+		                                  bitsPerPixel: UInt32(self.bitsPerPixel),
+		                                  colorSpace: Unmanaged.passUnretained(self.colorSpace!),
+		                                  bitmapInfo: self.bitmapInfo,
+		                                  version: 0, decode: nil, renderingIntent: .defaultIntent)
 
 		var sourceBuffer = vImage_Buffer()
 		defer
 		{
-			sourceBuffer.data.deallocate()
+			sourceBuffer.data?.deallocate()
 		}
 
 		var error: Int = kvImageNoError
 		error = vImageBuffer_InitWithCGImage(&sourceBuffer, &format, nil, self, numericCast(kvImageNoFlags))
-		guard error == kvImageNoError else
+		guard error == kvImageNoError
+		else
 		{
 			return nil
 		}
@@ -65,9 +66,9 @@ public extension CGImage
 		}
 
 		var destBuffer = vImage_Buffer(data: destData,
-									   height: vImagePixelCount(newHeight),
-									   width: vImagePixelCount(newWidth),
-									   rowBytes: destBytesPerRow)
+		                               height: vImagePixelCount(newHeight),
+		                               width: vImagePixelCount(newWidth),
+		                               rowBytes: destBytesPerRow)
 
 		if colorSpace?.model == .rgb
 		{
@@ -82,9 +83,10 @@ public extension CGImage
 
 		error = kvImageNoError
 		let resizedImageReference = vImageCreateCGImageFromBuffer(&destBuffer, &format, nil,
-																  nil, numericCast(kvImageNoFlags), &error)
+		                                                          nil, numericCast(kvImageNoFlags), &error)
 
-		guard error == kvImageNoError, let resizedImage = resizedImageReference?.takeRetainedValue() else
+		guard error == kvImageNoError, let resizedImage = resizedImageReference?.takeRetainedValue()
+		else
 		{
 			return nil
 		}