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https://github.com/alladinian/histogramview
A SwiftUI view for displaying image histograms
https://github.com/alladinian/histogramview
graphics histogram image ios macos swift swiftui
Last synced: about 1 month ago
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A SwiftUI view for displaying image histograms
- Host: GitHub
- URL: https://github.com/alladinian/histogramview
- Owner: alladinian
- Created: 2021-10-20T14:58:14.000Z (about 3 years ago)
- Default Branch: main
- Last Pushed: 2021-10-20T16:08:50.000Z (about 3 years ago)
- Last Synced: 2024-10-10T22:42:10.506Z (about 1 month ago)
- Topics: graphics, histogram, image, ios, macos, swift, swiftui
- Language: Swift
- Homepage:
- Size: 7.81 KB
- Stars: 28
- Watchers: 5
- Forks: 5
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# HistogramView
A SwiftUI view for displaying image histograms.
## How do I use it?
It's as simple as:
``` swift
HistogramView(image: myImage)
```
*Note:* Both `UIImage` & `NSImage` are supported (by the `HistogramImage` typealias, depending on the platform).
## What options do I have for configuration?
The initializer supports channel opacity, blendMode and scale for the final graph.
``` swift
/// 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
```
## How fast is this thing?
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).
## How is the graph curve produced?
Each channel is a `SwiftUI` `Path` that uses [Hermite interpolation](https://en.wikipedia.org/wiki/Hermite_interpolation) for generating a continous curve.
The actual implementation for the interpolator is taken from [@FlexMonkey's implementation](https://github.com/FlexMonkey/Filterpedia/blob/7a0d4a7070894eb77b9d1831f689f9d8765c12ca/Filterpedia/components/HistogramDisplay.swift#L228) (part of the [Filterpedia](https://github.com/FlexMonkey/Filterpedia) project) and adapted to be used on `Path` instead of `UIBezierPath`.
## Authors
Vasilis Akoinoglou, [email protected]