I am getting unsupported parameter combination CGBitmap error with swift

Question

I am trying to create a CGContext in swift. It compiles but throws an error at runtime.

let colorSpace:CGColorSpace = CGColorSpaceCreateDeviceRGB()
let context:CGContext = CGBitmapContextCreate(nil, 20, 20, 8, 0, colorSpace, CGBitmapInfo.AlphaInfoMask)
CGColorSpaceRelease(colorSpace);

....

And the error is:

Error: CGBitmapContextCreate: unsupported parameter combination: 8 integer bits/component; 32 bits/pixel; 3-component color space; unrecognized; 96 bytes/row.
fatal error: Can't unwrap Optional.None

score 63 · Accepted Answer · edited Nov 21 '14 at 22:26

63

Just in case somebody is running into the same problem. The snippet below finally works.

let colorSpace:CGColorSpace = CGColorSpaceCreateDeviceRGB()
let bitmapInfo = CGBitmapInfo(CGImageAlphaInfo.PremultipliedLast.rawValue)
let context = CGBitmapContextCreate(nil, UInt(rect.size.width), UInt(rect.size.height), 8, 0, colorSpace, bitmapInfo)

It generates a 32 bit RGBA context in swift

edited Nov 21 '14 at 22:26

Robert

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answered Jun 09 '14 at 09:59

loopmasta

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With the current version of Swift (I'm using Xcode 6.1): let bitmapInfo = CGBitmapInfo(CGImageAlphaInfo.PremultipliedLast.rawValue) – Ryan H. Oct 28 '14 at 00:17
4

And with the current version of the Xcode is now: let context = CGBitmapContextCreate(nil, Int(rect.size.width), Int(rect.size.height), 8, 0, colorSpace, bitmapInfo) – Janusz Chudzynski May 22 '15 at 15:43
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Swift 2.0 actually expects a `UInt32` instead of a `CGBitMapInfo` object, so in Swift 2.0 use `let context = CGBitmapContextCreate(nil, Int(rect.size.width), Int(rect.size.height), 8, 0, colorSpace, bitmapInfo.rawValue)`. <- notice how we convert `CGBitMapInfo` to `UInt32` by using its `rawValue` – the_critic Sep 11 '15 at 13:22
Swift 2 let context = CGBitmapContextCreate(nil, width, height, bitsPerComponent, bytesPerRow, colourSpace, CGBitmapInfo.ByteOrder32Little.rawValue) – Khaled Annajar Oct 10 '16 at 14:12
I want to use other that PremultipliedLast but if I am using none, first or last context become nil – Iraniya Naynesh Jul 05 '18 at 12:30

score 18 · Answer 2 · answered Oct 27 '16 at 10:09

Updated for Swift 3:

    let colorSpace = CGColorSpaceCreateDeviceRGB()
    let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.premultipliedLast.rawValue)
    guard let context = CGContext.init(data: nil, width: Int(size.width), height: Int(size.height), bitsPerComponent: Int(bitsPerComponent), bytesPerRow: Int(bytesPerRow), space: colorSpace, bitmapInfo: UInt32(bitmapInfo.rawValue)) else {
        // cannot create context - handle error
    }

score 11 · Answer 3 · answered Sep 23 '15 at 19:50

In Swift 2.1 one can access the fields properly, and even OR them together:

let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.PremultipliedFirst.rawValue | CGBitmapInfo.ByteOrder32Little.rawValue)

let context = CGBitmapContextCreate(baseAddress, width, height, 8,
                bytesPerRow, colorSpace, bitmapInfo.rawValue);

Whole lot of 'rawValue' going on :)

You don't even need to separate out the bitmapInfo, and can do a one-liner:

let context = CGBitmapContextCreate(baseAddress, width, height, 8,
                bytesPerRow, colorSpace, CGImageAlphaInfo.PremultipliedFirst.rawValue | CGBitmapInfo.ByteOrder32Little.rawValue

Jawad Ali · Answer 4 · 2020-05-13T22:07:45.840

6

Updated for Swift 5:

 let colorSpace:CGColorSpace = CGColorSpaceCreateDeviceRGB()
 let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.premultipliedLast.rawValue)
 let context = CGContext(data: nil, width: UInt(rect.size.width), height: UInt(rect.size.height), bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: bitmapInfo.rawValue)

where rect has height and width

edited May 13 '20 at 22:07

answered Dec 11 '19 at 07:50

Jawad Ali

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"CGImageAlphaInfo.premultipliedLast.rawValue". Really, Apple? – Maury Markowitz Oct 25 '22 at 00:09

score 4 · Answer 5 · edited Dec 11 '19 at 08:33

I had some issues in Swift 1.2 using UInt, now I'm using Int and it's working. This Example shows how to convert an Image to a grayscale image.

let imageRect = self.myImage.frame

let colorSpace = CGColorSpaceCreateDeviceGray()
let width = imageRect.width
let height = imageRect.height

let bitmapInfo = CGBitmapInfo(CGImageAlphaInfo.None.rawValue)
let context = CGBitmapContextCreate(nil, Int(width), Int(height), 8, 0, colorSpace, bitmapInfo)

abdullahselek · Answer 6 · 2017-09-20T13:55:19.103

Suggested way compatible with both Xcode 8.3 and Xcode 9 which supports Swift 3 and Swift 4

let colorSpace = CGColorSpaceCreateDeviceRGB()
guard let bitmapContext = CGContext(data: nil, 
                                    width: Int(size.width),
                                    height: Int(size.height),
                                    bitsPerComponent: Int(bitsPerComponent),
                                    bytesPerRow: Int(bytesPerRow),
                                    space: colorSpace,
                                    bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue) else {
                                  return nil
    }

score 1 · Answer 7 · answered Apr 29 '16 at 21:05

1

In Swift 2.2:

let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.PremultipliedLast.rawValue).rawValue
let colorSpace = CGColorSpaceCreateDeviceRGB()
let context = CGBitmapContextCreate(nil, Int(width), Int(height), 8, 0, colorSpace, bitmapInfo)

answered Apr 29 '16 at 21:05

Sam Soffes

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score 0 · Answer 8 · answered Jun 08 '14 at 19:18

0

CGBitmapInfo.AlphaInfoMask is not a valid bitmap info.

Try setting CGBitmapInfo.AlphaLast or CGBitmapInfo.AlphaFirst.

answered Jun 08 '14 at 19:18

Goz

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This does not compile and i can not find CGBitmapInfo.AlphaLast or CGBitmapInfo.AlphaFirst in https://developer.apple.com/library/prerelease/ios/documentation/GraphicsImaging/Reference/CGBitmapContext/index.html#//apple_ref/c/func/CGBitmapContextCreate – loopmasta Jun 08 '14 at 20:31

I am getting unsupported parameter combination CGBitmap error with swift

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