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

Robert · Accepted Answer · 2014-11-21 22:26:01Z

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, 2014 at 22:26

Robert

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answered Jun 9, 2014 at 9:59

loopmasta

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5 Comments

Ryan H. Over a year ago

With the current version of Swift (I'm using Xcode 6.1): let bitmapInfo = CGBitmapInfo(CGImageAlphaInfo.PremultipliedLast.rawValue)

Janusz Chudzynski Over a year ago

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)

the_critic Over a year ago

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

Khaled Annajar Over a year ago

Swift 2 let context = CGBitmapContextCreate(nil, width, height, bitsPerComponent, bytesPerRow, colourSpace, CGBitmapInfo.ByteOrder32Little.rawValue)

Iraniya Naynesh Over a year ago

I want to use other that PremultipliedLast but if I am using none, first or last context become nil

Echelon · Accepted Answer · 2016-10-27 10:09:27Z

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 }

Graham Perks · Accepted Answer · 2015-09-23 19:50:22Z

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 · Accepted Answer · 2020-05-13 22:07:45Z

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

"CGImageAlphaInfo.premultipliedLast.rawValue". Really, Apple?

abdullahselek · Accepted Answer · 2017-09-20 13:55:19Z

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 }

pkamb · Accepted Answer · 2019-12-11 08:33:10Z

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)

Sam Soffes · Accepted Answer · 2016-04-29 21:05:57Z

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)

Goz · Accepted Answer · 2014-06-08 19:18:43Z

0

CGBitmapInfo.AlphaInfoMask is not a valid bitmap info.

Try setting CGBitmapInfo.AlphaLast or CGBitmapInfo.AlphaFirst.

answered Jun 8, 2014 at 19:18

Goz

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1 Comment

loopmasta Over a year ago

This does not compile and i can not find CGBitmapInfo.AlphaLast or CGBitmapInfo.AlphaFirst in developer.apple.com/library/prerelease/ios/documentation/…

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