A SwiftUI view for displaying image histograms.

It's as simple as:

HistogramView(image: myImage)

Note: Both UIImage & NSImage are supported (by the HistogramImage typealias, depending on the platform).

The initializer supports channel opacity, blendMode and scale for the final graph.

/// The opacity of each channel layer. Default is `1`
public let channelOpacity: CGFloat

/// The blend mode for the channel layers. Default is `.screen`
public let blendMode: BlendMode

/// The scale of each layer. Default is `1`
public let scale: CGFloat

Under the hood the histogram calculation is performed by Accelerate's vImageHistogramCalculation_ARGB8888 for RGB channels, so it's pretty fast actually. Fast enough to be perfomed synchronously (although didn't test it on gigantic images).

Each channel is a SwiftUI Path that uses Hermite interpolation for generating a continous curve. The actual implementation for the interpolator is taken from @FlexMonkey's implementation (part of the Filterpedia project) and adapted to be used on Path instead of UIBezierPath.

Vasilis Akoinoglou, [email protected]