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https://github.com/swiftgraphs/grape

A Swift library for graph visualization and efficient force simulation.
https://github.com/swiftgraphs/grape

force-directed-graphs graph physics-simulation simulation swift swiftui visualization

Last synced: about 2 months ago
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A Swift library for graph visualization and efficient force simulation.

Host: GitHub
URL: https://github.com/swiftgraphs/grape
Owner: SwiftGraphs
License: mit
Created: 2023-10-04T01:13:16.000Z (about 1 year ago)
Default Branch: main
Last Pushed: 2024-10-07T17:11:29.000Z (3 months ago)
Last Synced: 2024-10-27T03:58:26.012Z (about 2 months ago)
Topics: force-directed-graphs, graph, physics-simulation, simulation, swift, swiftui, visualization
Language: Swift
Homepage: https://swiftgraphs.github.io/Grape/Grape/documentation/grape/
Size: 24 MB
Stars: 243
Watchers: 6
Forks: 10
Open Issues: 1
Metadata Files:
- Readme: README.md
- License: LICENSE

Awesome Lists containing this project

README

        


  

  Grape






   

   

  



A Swift library for graph visualization and efficient force simulation.

  

  

  

  







## Examples

### Force Directed Graph

This is a force directed graph visualizing [the network of character co-occurence in _Les Misérables_](https://observablehq.com/@d3/force-directed-graph-component). Take a closer look at the animation:

https://github.com/swiftgraphs/Grape/assets/45376537/d80dc797-1980-4755-85b9-18ee26e2a7ff

Source code: [Miserables.swift](https://github.com/swiftgraphs/Grape/blob/main/Examples/ForceDirectedGraphExample/ForceDirectedGraphExample/Miserables.swift). 




### Force Directed Graph in visionOS

This is the same graph as the first example, rendered in `RealityView`:

https://github.com/swiftgraphs/Grape/assets/45376537/4585471e-2339-4aee-8f39-0c11fdfb6901

Source code: [ForceDirectedGraph3D/ContentView.swift](https://github.com/swiftgraphs/Grape/blob/main/Examples/ForceDirectedGraph3D/ForceDirectedGraph3D/ContentView.swift).




### Mermaid Visualization

Dynamical graph structure based on your input, with tap and drag gesture supports, all within 100 lines of view body.

https://github.com/swiftgraphs/Grape/assets/45376537/7c75d367-d5a8-4316-813b-288b375f513b

Source code: [MermaidVisualization.swift](https://github.com/swiftgraphs/Grape/blob/main/Examples/ForceDirectedGraphExample/ForceDirectedGraphExample/MermaidVisualization.swift)




  

    

### Lattice Simulation

A 36x36 force directed lattice.

https://github.com/swiftgraphs/Grape/assets/45376537/5b76fddc-dd5c-4d35-bced-29c01269dd2b

Source code: [Lattice.swift](https://github.com/swiftgraphs/Grape/blob/main/Examples/ForceDirectedGraphExample/ForceDirectedGraphExample/Lattice.swift)

  

### Dragging Gesture

An example rendering a ring with 60 vertices, with dragging gesture enabled.

https://github.com/swiftgraphs/Grape/assets/45376537/73213e7f-73ee-44f3-9b3e-7e58355045d2

Source code: [MyRing.swift](https://github.com/swiftgraphs/Grape/blob/main/Examples/ForceDirectedGraphExample/ForceDirectedGraphExample/MyRing.swift)







## Installation

To use Grape in an Xcode project by adding it to your project as a package:

```

https://github.com/li3zhen1/Grape

```

To use Grape in a [SwiftPM](https://swift.org/package-manager/) project, add this to your `Package.swift`:

``` swift

dependencies: [

    .package(url: "https://github.com/li3zhen1/Grape", from: "0.7.0")

]

```

```swift

.product(name: "Grape", package: "Grape"),

```

> [!NOTE]

> The `Grape` module relies on the [`Observation` framework](https://developer.apple.com/documentation/observation). It’s possible to backdeploy with community shims like [`swift-perception`](https://github.com/pointfreeco/swift-perception).

> 

> The `Grape` module may introduce breaking API changes in minor version changes before 1.0 release.

>

> The `ForceSimulation` module is stable in terms of public API now.







## Get started

Grape ships 2 modules:

- The `Grape` module allows you to create force-directed graphs in SwiftUI Views.

- The `ForceSimulation` module is the underlying mechanism of `Grape`, and it helps you to create more complicated or customized force simulations. It also contains a `KDTree` data structure built with performance in mind, which can be useful for spatial partitioning tasks.




### The `Grape` module

For detailed usage, please refer to [documentation](https://swiftgraphs.github.io/Grape/Grape/documentation/grape). A quick example here:

```swift

import Grape

struct MyGraph: View {

    // States including running status, transformation, etc.

    // Gives you a handle to control the states.

    @State var graphStates = ForceDirectedGraphState() 

    

    var body: some View {

        ForceDirectedGraph(states: graphStates) {

            

            // Declare nodes and links like you would do in Swift Charts.

            NodeMark(id: 0).foregroundStyle(.green)

            NodeMark(id: 1).foregroundStyle(.blue)

            NodeMark(id: 2).foregroundStyle(.yellow)

            Series(0..<2) { i in

                LinkMark(from: i, to: i+1)

            }

            

        } force: {

            LinkForce()

            CenterForce()

            ManyBodyForce()

        }

    }

}

```




### The `ForceSimulation` module

  Refer to the documentation or expand this section to find more about this module.

  

`ForceSimulation` module mainly contains 3 concepts, `Kinetics`, `ForceProtocol` and `Simulation`.



  



  

- `Kinetics` describes all kinetic states of your system, i.e. position, velocity, link connections, and the variable `alpha` that describes how "active" your system is.

- Forces are any types that conforms to `ForceProtocol`. This module provides most of the forces you will use in force directed graphs. And you can also create your own forces. They should be responsible for 2 tasks:

    - `bindKinetics(_ kinetics: Kinetics)`: binding to a `Kinetics`. In most cases the force should keep a reference of the `Kinetics` so they know what to mutate when `apply` is called.

    - `apply()`: Mutating the states of `Kinetics`. For example, a gravity force should add velocities on each node in this function.

- `Simulation` is a shell class you interact with, which enables you to create any dimensional simulation with velocity Verlet integration. It manages a `Kinetics` and a force conforming to `ForceProtocol`. Since `Simulation` only stores one force, you are responsible for compositing multiple forces into one.

- Another data structure `KDTree` is used to accelerate the force simulation with [Barnes-Hut Approximation](https://jheer.github.io/barnes-hut/).




The basic concepts of simulations and forces can be found here: [Force simulations - D3](https://d3js.org/d3-force/simulation). You can simply create simulations by using `Simulation` like this:

```swift

import simd

import ForceSimulation

// assuming you’re simulating 4 nodes

let nodeCount = 4

// Connect them

let links = [(0, 1), (1, 2), (2, 3), (3, 0)] 

/// Create a 2D force composited with 4 primitive forces.

let myForce = SealedForce2D {

    // Forces are namespaced under `Kinetics`

    // here we only use `Kinetics>`, i.e. `Kinetics2D`

    Kinetics2D.ManyBodyForce(strength: -30)

    Kinetics2D.LinkForce(

        stiffness: .weightedByDegree(k: { _, _ in 1.0 }),

        originalLength: .constant(35)

    )

    Kinetics2D.CenterForce(center: .zero, strength: 1)

    Kinetics2D.CollideForce(radius: .constant(3))

}

/// Create a simulation, the dimension is inferred from the force.

let mySimulation = Simulation(

    nodeCount: nodeCount,

    links: links.map { EdgeID(source: $0.0, target: $0.1) },

    forceField: myForce

) 

/// Force is ready to start! run `tick` to iterate the simulation.

for mySimulation in 0..<120 {

    mySimulation.tick()

    let positions = mySimulation.kinetics.position.asArray()

    /// Do something with the positions.

}

```

See [Example](https://github.com/swiftgraphs/Grape/tree/main/Examples/ForceDirectedGraphExample) for more details. 







## Roadmap

|   | 2D simd | ND simd | Metal |

| --- | --- | --- | --- |

| **NdTree** | ✅ | ✅ |  |

| **Simulation** | ✅ | ✅ |  |

|  LinkForce | ✅ | ✅ |  |

|  ManyBodyForce | ✅ | ✅ |  |

|  CenterForce | ✅ | ✅ |  |

|  CollideForce | ✅ | ✅ |  |

|  PositionForce | ✅ | ✅ |  |

|  RadialForce | ✅ | ✅ |  |

| **SwiftUI View** | ✅ |  |  |

|  Basic Visualization | ✅ |  |  |

|  Gestures | ✅ |  |  |

|  Node Styling | ✅ |  |  |

|  Link Styling | 🚧 |  |  |

|  Animatable Transition | 🚧 |  |  |







## Performance




#### Simulation

Grape uses simd to calculate position and velocity. Currently it takes **~0.005** seconds to iterate 120 times over the example graph(2D). (77 vertices, 254 edges, with manybody, center, collide and link forces. Release build on a M1 Max, [tested](https://github.com/swiftgraphs/Grape/blob/main/Tests/ForceSimulationTests/MiserableGraphTest.swift) with command `swift test -c release`)

For 3D simulation, it takes **~0.008** seconds for the same graph and same configs.

> [!IMPORTANT]

> Due to heavy use of generics (some are not specialized in Debug mode), the performance in Debug build is ~100x slower than Release build. Grape might ship a version with pre-inlined generics to address this problem.




#### KDTree

The `BufferedKDTree` from this package is **~22x** faster than `GKQuadtree` from Apple’s GameKit, according to this [test case](https://github.com/swiftgraphs/Grape/blob/main/Tests/ForceSimulationTests/GKTreeCompareTest.swift). However, please note that comparing Swift structs with NSObjects is unfair, and their behaviors are different.




## Credits

This library has been greatly influenced by the outstanding work done by [D3.js (Data-Driven Documents)](https://d3js.org).