RecursiveAI.OneImage.Svg 1.3.0

OneImage.Svg

SVG for OneImage: registers SVG (and gzip-compressed .svgz) as an image format that is drawn directly at the size you ask for. Pure C# with no dependency beyond OneImage, OneImage.Text and .NET.

dotnet add package RecursiveAI.OneImage.Svg

using OneImage;
using OneImage.Svg;

var config = new ImageConfiguration().Add(SvgFormat.Instance);   // not in ImageConfiguration.Default, so it trims away when unused
var load = new LoadOptions { Configuration = config };

ImageInfo info = Image.Identify("logo.svg", load);                       // natural size, nothing drawn
Image.Load("logo.svg", load).Resize(width: 400).Save("logo-400.png");     // drawn at 400 px, not scaled up from the natural size
Image.Thumbnail("logo.svg", 64, upscale: true, loadOptions: load).Save("logo-64.webp");

The output is 8-bit sRGB RGBA, transparent where nothing is drawn. Only the shapes under a requested region are drawn for it, so large renders stream in tiles.

What it draws

Static SVG 1.1 and SVG Tiny-style content, plus the parts of SVG 2 and CSS that documents rely on: shapes and paths with fills and strokes (caps, joins, dashes, markers), gradients and patterns, opacity, blend modes and isolated groups, transforms, nested svg, use and symbol, clip paths and masks, style sheets with the usual selectors, switch, data: images (any raster format OneImage reads, and nested SVG), the filter primitives and CSS filter functions, and text including textPath, bidirectional text, vertical writing modes and decorations.

Text needs fonts. Add font files through SvgFontOptions (TrueType, OpenType/CFF, collections, WOFF and WOFF2), or let it use the installed ones:

var fonts = new SvgFontOptions { UseSystemFonts = false };
fonts.AddFont("Roboto-Regular.ttf");
var config = new ImageConfiguration().Add(new SvgFormat(fonts: fonts));

Text whose font cannot be found draws nothing. The default font size (CSS medium) is 16 pixels, as in browsers; SvgFontOptions.DefaultFontSize changes it.

What it never does

External references (other files, URLs), @font-face, scripts, animation (SMIL) and foreignObject are never loaded or run, and the XML parser refuses DTDs and entity declarations, so a document cannot read files, reach the network or expand entities. A reference that cannot be resolved is treated as SVG's error handling says (the element is not drawn).

Limits

Documents are untrusted input. SvgLimits bounds document size, element count and nesting, attributes and names, style sheet size and matching work, use fan-out and reference depth, layers, pattern tiles, embedded images, filter size, text and path segments. A document that exceeds one fails with ImageLimitException, before the memory it would need is allocated; the load call's ImageLimits (pixels, dimension, expansion ratio) apply on top. Pass your own with new SvgFormat(new SvgLimits { ... }).

The SVG page in the repository covers the design, the limits table, how SVG features map to OneImage operations, and the conformance results.