Use cgImage.bytesPerRow instead of width

[YuAo]

Because the bitmap data allocated may be padded.

[jathu]

@YuAo can you provide more information? What do you mean by the data allocated may be padded?

[YuAo]

@jathu When an image is stored in memory, the memory buffer may contain extra padding bytes after each row of pixels. bytesPerRow is number of bytes allocated for a single row of an image.

Examples:

let cgContext: CGContext = CGContext(data: nil, width: 100, height: 100, bitsPerComponent: 8, bytesPerRow: 0, space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: CGBitmapInfo.byteOrder32Little.rawValue | CGImageAlphaInfo.premultipliedFirst.rawValue)!
let image: CGImage = cgContext.makeImage()!
image.bytesPerRow //448
image.width * 4 //400

This image object here has the bytesPerRow of 448.

---

In your case, you use UIGraphicsGetImageFromCurrentImageContext to generate images.

UIGraphicsBeginImageContextWithOptions(CGSize(width: 100, height: 100), false, 1.0)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
image!.cgImage!.bytesPerRow //416
image!.cgImage!.width * 4 //400

This image object here has the bytesPerRow of 416.

---

So, the index of pixel byte at (x,y) should be y * bytesPerRow + x * 4 instead of ((width * y) + x) * 4.

May be the underlying problem for #65

[jathu]

Yup, that makes sense. I think this looks good. Can you also bump the version from 2.2.0 to 2.3.0?

[YuAo]

Can you also bump the version from 2.2.0 to 2.3.0?

Done.

[jathu]

Ah, I should've specified the locations but we'll also need to update the version here:

UIImageColors/UIImageColors/Supporting Files/Info.plist

Line 18 in 8b37548

<string>2.2.0</string>