Class SkiaCoverageArrowRenderer

Namespace

EncDotNet.S100.Renderers.Skia

Assembly

EncDotNet.S100.Renderers.Skia.dll

Draws oriented overlay symbols (e.g. S-111 surface-current arrows) from a SymbolScheme directly onto an SKCanvas, with no Mapsui dependency. This is the headless, direct-Skia analogue of MapsuiCoverageArrowRenderer: it shares the same per-band scaling contract (S-111 Ed 2.0.0, content/S111/pc/Rules/select_arrow.xsl) and palette-token SVG processing, but rasterises each arrow with Svg.Skia.SKSvg and projects grid-cell centres through WebMercator instead of Mapsui's navigator.

public sealed class SkiaCoverageArrowRenderer

Inheritance

object

SkiaCoverageArrowRenderer

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Properties

BaseSymbolScale

Multiplier applied to each band's scale factor. Callers fold the user-facing RenderContext.SymbolScale into this value so the symbol-scale preference continues to affect arrow size.

public double BaseSymbolScale { get; init; }

Property Value

double

Palette

The colour palette used to resolve SVG CSS fill/stroke tokens (e.g. fSCBN1 → palette token SCBN1).

public ColorPalette? Palette { get; init; }

Property Value

ColorPalette

SymbolProvider

Returns raw SVG content for a symbol reference name (e.g. "SCAROW01"), or null when unavailable.

public required Func<string, string?> SymbolProvider { get; init; }

Property Value

Func<string, string>

Methods

Draw(SKCanvas, StyledCoverageLayer, ICrsTransform, Func<(double X, double Y), (float X, float Y)>)

Draws the layer's symbol scheme onto canvas. Each grid cell that survives thinning becomes one rotated, palette-coloured symbol placed at its projected pixel position. No-ops when the layer has no symbol scheme.

public void Draw(SKCanvas canvas, StyledCoverageLayer layer, ICrsTransform nativeToWgs84, Func<(double X, double Y), (float X, float Y)> project)

Parameters

canvas SKCanvas

Target canvas (already sized / cleared by the caller).

layer StyledCoverageLayer

The styled coverage layer carrying the symbol scheme.

nativeToWgs84 ICrsTransform

Transform from the grid's native CRS to WGS84 (EPSG:4326); pass Instance for geographic grids.

project Func<(double X, double Y), (float X, float Y)>

Projects an EPSG:3857 (x, y) world coordinate to an output pixel.

Remarks

Thinning uses the S-98 Appendix G-1.1 grid algorithm (ThinGrid(int, int, ReadOnlySpan<double>, ReadOnlySpan<double>, ReadOnlySpan<float>, ReadOnlySpan<float>, double, SymbolRect, double, List<int>)) over the canvas's clip bounds, with the same arrow length and Rmax as MapsuiCoverageArrowRenderer, so a headless render and the viewer draw the same arrows for the same view.