A simple graph editor for Blazor.
The WASM sample project can be demoed at https://kristofferstrube.github.io/Blazor.GraphEditor/
You need to install .NET 7.0 or newer to use the library.
You can install the package via NuGet with the Package Manager in your IDE or alternatively using the command line:
dotnet add package KristofferStrube.Blazor.SVGEditorThe package can be used in Blazor WebAssembly and Blazor Server projects. In the samples folder of this repository, you can find two projects that show how to use the SVGEditor component in both Blazor Server and WASM.
You need to reference the package to use it in your pages. This can be done in _Import.razor by adding the following.
@using KristofferStrube.Blazor.GraphEditorTo use the component in your pages you also need to register som services in your service collection. We have a single method that is exposed via the Blazor.SVGEditor library which adds all these services.
var builder = WebAssemblyHostBuilder.CreateDefault(args);
builder.RootComponents.Add<App>("#app");
builder.RootComponents.Add<HeadOutlet>("head::after");
builder.Services.AddScoped(sp => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });
// Adding the needed services.
builder.Services.AddSVGEditor();
await builder.Build().RunAsync();The libraries that the component uses also need to have some stylesheets and scripts added to function.
For this, you need to insert the following tags in the <head> section of your index.html or Host.cshtml file:
<link href="_content/BlazorColorPicker/colorpicker.css" rel="stylesheet" />
<link href="_content/Blazor.ContextMenu/blazorContextMenu.min.css" rel="stylesheet" />
<link href="_content/KristofferStrube.Blazor.SVGEditor/kristofferStrubeBlazorSVGEditor.css" rel="stylesheet" />The library uses Scoped CSS, so you must include your project-specific .styles.css CSS file in your project for the scoped styles of the library components. An example is in the test project in this repo:
<link href="KristofferStrube.Blazor.GraphEditor.WasmExample.styles.css" rel="stylesheet" />At the end of the file, after you have referenced the Blazor Server or Wasm bootstrapper, insert the following:
<script src="_content/Blazor.ContextMenu/blazorContextMenu.min.js"></script>Now, you are ready to use the component in your page. A minimal example of this would be the following:
<div style="height:80vh;">
<GraphEditor
@ref=GraphEditor
TNode="Page"
TEdge="Transition"
NodeIdMapper="n => n.id"
NodeRadiusMapper="n => n.size"
NodeColorMapper="n => n.color"
EdgeFromMapper="e => e.from"
EdgeToMapper="e => e.to"
EdgeWidthMapper="e => e.weight*5"
EdgeSpringConstantMapper="e => e.weight"
EdgeSpringLengthMapper="e => e.length"
/>
</div>
@code {
private GraphEditor<Page, Transition> GraphEditor = default!;
private bool running = true;
protected override async Task OnAfterRenderAsync(bool firstRender)
{
if (!firstRender) return;
while (!GraphEditor.IsReadyToLoad)
{
await Task.Delay(50);
}
var pages = new List<Page>() { new("1", size: 60), new("2", "#3333AA"), new("3", "#AA33AA"), new("4", "#AA3333"), new("5", "#AAAA33"), new("6", "#33AAAA"), new("7"), new("8") };
var edges = new List<Transition>() {
new(pages[0], pages[1], 1),
new(pages[0], pages[2], 1),
new(pages[0], pages[3], 1),
new(pages[0], pages[4], 1),
new(pages[0], pages[5], 1),
new(pages[0], pages[6], 1),
new(pages[6], pages[7], 2, 150) };
await GraphEditor.LoadGraph(pages, edges);
DateTimeOffset startTime = DateTimeOffset.UtcNow;
while (running)
{
await GraphEditor.ForceDirectedLayout();
/// First 5 seconds also fit the viewport to all the nodes and edges in the graph.
if (startTime - DateTimeOffset.UtcNow < TimeSpan.FromSeconds(5))
GraphEditor.SVGEditor.FitViewportToAllShapes(delta: 0.8);
await Task.Delay(1);
}
}
public record Page(string id, string color = "#66BB6A", float size = 50);
public record Transition(Page from, Page to, float weight, float length = 200);
public void Dispose()
{
running = false;
}
}