CODEWITHSUNDEEP
pngcore-animationcgcontext
Pavel Gubarev
Pavel Gubarev

Reputation: 89

CALayers to PNG: strange color changes

My task is to render my CALayer tree to PNG. When I do this I get the image which is generally OK, but the colors slightly change.

Here's my code:

I render the view into context

   let contentsScale = view.layer!.contentsScale
        let width = Int(view.frame.width * contentsScale)
        let height = Int(view.frame.height * contentsScale)



    let bytesPerRow = width * 4
    let context = CGContext(
        data: nil,
        width: width,
        height: height,
        bitsPerComponent: 8,
        bytesPerRow: bytesPerRow,
        space: CGColorSpace(name: CGColorSpace.genericRGBLinear)! ,
        bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue
        )!

    if needsAntialiased {
        context.setShouldAntialias(false)
    }

    view.layer!.render(in: context)

And then I save the context into PNG:

let image = context.makeImage()!

 guard let destination = CGImageDestinationCreateWithURL(destinationURL as CFURL, kUTTypePNG, 1, nil) else { return false }

        CGImageDestinationAddImage(destination, image, nil)
        return CGImageDestinationFinalize(destination)

At some point my colors change. The layer that should be filled with B30000 becomes 870000.

I suppose it has something to do with colorspace. But I don't know what should I change genericRGBLinear for to preserve my colors.

Any ideas where the problem can be?

Upvotes: 0

Views: 79

Answers (1)

Pavel Gubarev
Pavel Gubarev

Reputation: 89

So the solution was to create fillColor for layer in the same color space

    let colorSpace = CGColorSpace(name: CGColorSpace.genericRGBLinear)!

    layer.fillColor = CGColor(colorSpace: colorSpace, components: components)

Upvotes: 1

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