VelloSharp.Rendering

VelloSharp.Rendering packages shared rendering helpers that sit on top of the core VelloSharp APIs. It provides host-agnostic render path utilities and buffer descriptors so platforms can feed Renderer.Render without duplicating stride and format negotiation code.

Getting Started

1. Install the package with dotnet add package VelloSharp.Rendering.
2. Import the namespace via using VelloSharp.Rendering; wherever you assemble render targets.
3. Describe your output surface with RenderTargetDescriptor, supplying width, height, pixel format, and stride.
4. Call VelloRenderPath.Render with a Renderer, Scene, and either a managed Span<byte> buffer or an unmanaged pointer.

Usage Example

using System;
using System.Buffers;
using System.Numerics;
using VelloSharp;
using VelloSharp.Rendering;

var descriptor = new RenderTargetDescriptor(
    Width: 1280,
    Height: 720,
    Format: RenderFormat.Bgra8,
    StrideBytes: 1280 * 4);

var buffer = ArrayPool<byte>.Shared.Rent(descriptor.RequiredBufferSize);
try
{
    using var scene = new Scene();
    using var renderer = new Renderer(descriptor.Width, descriptor.Height);

    // Populate the scene with Vello primitives.
    var path = new PathBuilder()
        .MoveTo(0, 0)
        .LineTo(1280, 0)
        .LineTo(1280, 720)
        .LineTo(0, 720)
        .Close();
    scene.FillPath(path, FillRule.NonZero, Matrix3x2.Identity, RgbaColor.FromBytes(0, 144, 255));

    var renderParams = new RenderParams(descriptor.Width, descriptor.Height, RgbaColor.FromBytes(18, 18, 18));
    VelloRenderPath.Render(renderer, scene, buffer.AsSpan(0, descriptor.RequiredBufferSize), renderParams, descriptor);
}
finally
{
    ArrayPool<byte>.Shared.Return(buffer);
}

Next Steps

• Keep RenderTargetDescriptor alongside platform-specific swapchain or framebuffer code to validate buffer sizes before calling into the renderer.
• When interoperating with native surfaces, use the VelloRenderPath.Render overload that accepts an IntPtr to avoid extra copies.
• Combine the helpers with VelloSharp.Integration packages (Avalonia, WPF, WinForms, Uno) to present the rendered buffers inside UI frameworks.