CODEWITHSUNDEEP
swift
HixField
HixField

Reputation: 3796

Extract Float array from Data

I have a function that receives a Data object together with a width and height. The data is a so called "normalised" image in binary form. Each pixel consists out of 3 Float values for the R, G, B colors ranging from 0 -> 1.0 (instead of the typical 0-255 for UInt8 values, but here we have floats). In fact its a sort of 2 dimensional array with a width and a height like this:

enter image description here

How can extract the R, G, B values as Swift floats from the Data object? This is what I came up with so far:

    func convert(data: Data, width: Int, height: Int) {
        let sizeFloat = MemoryLayout.size(ofValue: CGFloat.self)
        for x in 0...width {
            for y in 0...height {
                let index = ( x + (y * width) ) * sizeFloat * 3
                let dataIndex = Data.Index(???)
                data.copyBytes(to: <#T##UnsafeMutableBufferPointer<DestinationType>#>??, from: <#T##Range<Data.Index>?#>???)
           let Red = ....
           let Green = ...
           let Blue = ...
            }
        }
    }

Upvotes: 2

Views: 1960

Answers (2)

Martin R
Martin R

Reputation: 539975

You can use withUnsafeBytes() to access the raw data as an array of Float values:

func convert(data: Data, width: Int, height: Int) {
    data.withUnsafeBytes { (floatPtr: UnsafePointer<Float>) in
        for x in 0..<width {
            for y in 0..<height {
                let index = (x + y * width) * 3
                let red = floatPtr[index]
                let green = floatPtr[index+1]
                let blue = floatPtr[index+2]
                // ...
            }
        }
    }
}

Upvotes: 3

Tom Edwards
Tom Edwards

Reputation: 124

var r= data[0];
var g = data[1];
var b = data[2];

element.background-color =rgba(r,g,b,1)

perhaps your looking for something like this?

Upvotes: -1

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