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KristofferStrube.Blazor.SVGEditor

License: MIT GitHub issues GitHub forks GitHub stars NuGet Downloads (official NuGet)

A basic HTML SVG Editor written in Blazor.

Showcase

Demo

The WASM sample project can be demoed at https://kristofferstrube.github.io/Blazor.SVGEditor/

Getting Started

Prerequisites

You need to install .NET 7.0 or newer to use the library.

Download .NET 7

Installation

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.SVGEditor

The 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.

Import

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.SVGEditor

Add to service collection

To use the component in your pages you also need to register som services in your service collection. We have made a single method that allows you to add the needed service which you use like so:

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();

Include needed stylesheets and scripts

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.SVGEditor.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>

Adding the component to a site.

Now, you are ready to use the component in your page. A minimal example of this would be the following:

<div style="height:80vh">
    <SVGEditor Input=@Input InputUpdated="(string s) => { Input = s; StateHasChanged(); }" />
</div>

@code {
    private string Input = @"<rect x=""0"" y=""0"" height=""200"" width=""200"" fill=""green"" stroke=""blue"" stroke-width=""2""></rect>";
}

Tag type support and attributes

  • RECT (x, y, width, height, fill, stroke, stroke-width, stroke-linecap, stroke-linejoin, stroke-offset)
  • CIRCLE (cx, cy, r, fill, stroke, stroke-width, stroke-linecap, stroke-linejoin, stroke-offset)
  • ELLIPSE (cx, cy, rx, ry, fill, stroke, stroke-width, stroke-linecap, stroke-linejoin, stroke-offset)
  • POLYGON (points, fill, stroke, stroke-width, stroke-linecap, stroke-linejoin, stroke-offset)
  • POLYLINE (points, fill, stroke, stroke-width, stroke-linecap, stroke-linejoin, stroke-offset)
  • LINE (x1, y1, x2, y2, fill, stroke, stroke-width, stroke-linecap, stroke-linejoin, stroke-offset)
  • TEXT (x, y, style:(font-size,font-weight,font-family), fill, stroke, stroke-width, stroke-linecap, stroke-linejoin, stroke-offset)
  • PATH (d, fill, stroke, stroke-width, stroke-linecap, stroke-linejoin, stroke-offset)
    • Movements
    • Lines
    • Vertical Lines
    • Horizontal Lines
    • Close Path
    • Cubic Bézier Curve
      • Shorthand aswell
    • Quadratic Bézier Curve
      • Shorthand aswell
    • Elliptical Arc Curve
      • Needs more work for radi interaction
  • G (fill, stroke, stroke-width, stroke-linecap, stroke-linejoin, stroke-offset)
    • Missing scaling of children
  • ANIMATE
    • Support for showing all Animate tags when Playing
    • Support for editing Fill animation values
    • Support for editing Stroke animation values
    • Support for editing Stroke Offset values
  • LINEARGRADIENT (x1, x2, y1, y2, and stops)

Current goals

  • Add support for touch devices
  • Support errors better to recover instead of crashing when parsing malformed SVGs.

Issues

Feel free to open issues on the repository if you find any errors with the package or have wishes for features.

Related articles:

Diagram of relation between core types in the project.

  graph LR;
      subgraph Shapes
      Circle
      Ellipse
      Line
      Text
      Path
      Polygon
      Polyline
      Rect
      G
      end
      subgraph Path Instructions
      ClosePathInstruction
      CubicBézierCurveInstruction
      EllipticalArcInstruction
      HorizontalLineInstruction
      LineInstruction
      MoveInstruction
      QuadraticBézierCurveInstruction
      ShorthandCubicBézierCurveInstruction
      ShorthandQuadraticBézierCurveInstruction
      VerticalLineInstruction
      end
      ISVGElement[[ISVGElement]]
      Shape[[Shape]]
      BasePathInstruction[[BasePathInstruction]]
      BaseControlPointPathInstruction[[BaseControlPointPathInstruction]]
      IPathInstruction[[IPathInstruction]]
      Shape-.->ISVGElement;
      SVG------ISVGElement
      G---ISVGElement;
      Path-.->Shape;
      Path-----IPathInstruction
      G-.->Shape;
      Circle-.->Shape;
      Ellipse-.->Shape;
      Line-.->Shape;
      Text-.->Shape;
      Polygon-.->Shape;
      Polyline-.->Shape;
      Rect-.->Shape;
      ClosePathInstruction-->BasePathInstruction
      CubicBézierCurveInstruction-->BaseControlPointPathInstruction
      EllipticalArcInstruction-->BasePathInstruction
      HorizontalLineInstruction-->BasePathInstruction
      LineInstruction-->BasePathInstruction
      MoveInstruction-->BasePathInstruction
      QuadraticBézierCurveInstruction-->BaseControlPointPathInstruction
      ShorthandCubicBézierCurveInstruction-->BaseControlPointPathInstruction
      ShorthandQuadraticBézierCurveInstruction-->BaseControlPointPathInstruction
      VerticalLineInstruction-->BasePathInstruction
      BaseControlPointPathInstruction-->BasePathInstruction
      BasePathInstruction-->IPathInstruction
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