Hit Testing and Scene Inspection

SKSvg exposes both broad inspection-oriented hit testing and topmost routed-target hit testing. The retained scene graph powers both APIs.

Hit testing elements in picture coordinates

Use HitTestElements(...) when you want every matching authored element, not just the routed target:

using System.Linq;
using ShimSkiaSharp;
using Svg.Skia;

using var svg = new SKSvg();
svg.Load("image.svg");

var element = svg.HitTestElements(new SKPoint(10, 10)).FirstOrDefault();
var elementsInBox = svg.HitTestElements(new SKRect(0, 0, 40, 40)).ToList();
var topmost = svg.HitTestTopmostElement(new SKPoint(10, 10));

Inspecting retained scene nodes

Use the scene-node APIs when you want compiled bounds, hit-test targets, or node metadata instead of just the authored SvgElement:

using System.Linq;
using ShimSkiaSharp;
using Svg.Skia;

using var svg = new SKSvg();
svg.Load("image.svg");

var node = svg.HitTestTopmostSceneNode(new SKPoint(10, 10));
var nodesInBox = svg.HitTestSceneNodes(new SKRect(0, 0, 40, 40)).ToList();

var targetId = node?.HitTestTargetElement?.ID;
var bounds = node?.TransformedBounds;

Hit testing on transformed canvases

When the picture is drawn through a transformed canvas, convert the pointer or selection rectangle back into picture space first:

using ShimSkiaSharp;
using Svg.Skia;

using var svg = new SKSvg();
svg.Load("image.svg");

var canvasMatrix = SKMatrix.CreateScale(2f, 2f);
if (svg.TryGetPicturePoint(new SKPoint(50, 50), canvasMatrix, out var picturePoint))
{
    var hits = svg.HitTestElements(picturePoint);
}

There are also overloads that take the canvas matrix directly:

HitTestElements(SKPoint point, SKMatrix canvasMatrix)
HitTestElements(SKRect rect, SKMatrix canvasMatrix)
HitTestSceneNodes(SKPoint point, SKMatrix canvasMatrix)
HitTestSceneNodes(SKRect rect, SKMatrix canvasMatrix)
HitTestTopmostSceneNode(SKPoint point, SKMatrix canvasMatrix)
HitTestTopmostElement(SKPoint point, SKMatrix canvasMatrix)

Avalonia control hit testing

The Skia-backed Avalonia.Svg.Skia.Svg control exposes HitTestElements(Point point) in control coordinates, so the control handles the coordinate transform for you.

The shared hit-test path now also respects typed pointer-events values, geometry-aware element bounds, and topmost-target routing used by SvgInteractionDispatcher.

Use HitTestElements(...) when you want all matches. Use HitTestTopmostElement(...) when you need the routed pointer target. Use HitTestSceneNodes(...) when diagnostics or editor tooling need access to retained-scene metadata.

For retained-scene lookup helpers, continue with Retained Scene Graph Usage. For the higher-level routed input and animation playback surface, continue with Interaction and Animation.