Class S100VectorSceneRenderer

Namespace

EncDotNet.S100.Renderers.Mapsui

Assembly

EncDotNet.S100.Renderers.Mapsui.dll

The TiledScene ("B") render subsystem, Phase 1: a Mapsui custom layer renderer that draws the chart base plane by rasterising the backend-agnostic VectorScene IR directly — bypassing Mapsui's feature / style / layer walk entirely — on a worker thread, then compositing the result on the UI/render thread as a single translated SKImage blit. See docs/design/S100-Render-Subsystem-Design.md (§3, §4, Phase 1).

public static class S100VectorSceneRenderer

Inheritance

object

S100VectorSceneRenderer

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

Straight from the IR. This renderer consumes the fully-resolved VectorScene (world coords in EPSG:3857, sizes in display px, colours resolved, symbols pre-processed, patterns pre-rasterised) and draws it with SkiaDisplayListRenderer, so the base plane never touches Mapsui's feature/style model — unlike the retired Mapsui snapshot arm (issue #600), which recorded what Mapsui would draw by riding GetFeatures / SortFeatures and the per-feature style dispatch.

Off the synchronous loop (the Phase 1 goal). The expensive rasterisation never runs on the render thread. Each frame the renderer blits the best available image under a pure translation (north-up, constant resolution ⇒ the world→screen projection is an affine translation, identical to the snapshot path's math). When the current image no longer covers the viewport (zoom, or a pan past the recorded MarginPx margin) a fresh whole-viewport-plus-margin raster is scheduled on a worker; the stale image keeps blitting (translated) until the new one publishes, at which point the layer's per-session redraw sink marshals a single repaint that swaps it in. Jobs are coalesced latest-wins per layer so a fast gesture never queues a backlog.

Single surface (Phase 1 scope). One image per layer covering the viewport + margin — no tile pyramid, no prediction, no disk cache yet (those are Phases 2–4). A rotated viewport (course-up) breaks the translate-only blit and is out of v1 scope, so it falls back to drawing nothing for that frame (north-up is the only supported orientation).

Fidelity. The scene bound to the layer via BindScene(ILayer, VectorScene) is built by MapsuiDisplayListRenderer with the pattern resolver set, so area pattern fills are present in the IR (unlike the Mapsui arm, which lowers patterns through a separate post-IR phase). Scale-visibility (S-100 Part 9 §11.1, the per-op SCAMIN carried in the IR) is honoured against the live viewport's scale denominator, matching the A arm's scale-dependent show/hide.

Selection. A fresh vector layer is tagged with RendererName when SceneMode selects the single-surface arm (Single); the tagging is done by MapsuiDisplayListRenderer. EncDotNet.S100.Renderers.Mapsui.S100VectorSceneRenderer.Register() wires the renderer into Mapsui once at startup.

Fields

RendererName

The Mapsui.Layers.ILayer.CustomLayerRendererName value that routes a layer through this renderer. Set on the vector layer by MapsuiDisplayListRenderer when the TiledScene subsystem is active.

public const string RendererName = "s100.vector.scene"

Field Value

string

Properties

MarginPx

Margin, in screen pixels, rasterised around the viewport on every edge so a pan reveals already-rendered content out to the margin before a re-raster is needed. Read once from S100_VECTOR_SCENE_MARGIN (default 256).

public static double MarginPx { get; }

Property Value

double

Methods

BindScene(ILayer, VectorScene)

Binds the fully-resolved VectorScene that this renderer rasterises for layer. Called by MapsuiDisplayListRenderer when it produces a layer for the active TiledScene subsystem. Binding a new scene invalidates any cached image so the next frame re-rasterises.

public static void BindScene(ILayer layer, VectorScene scene)

Parameters

layer ILayer

The Mapsui layer the scene belongs to.

scene VectorScene

The resolved scene IR (with pattern fills).

Render(SKCanvas, Viewport, ILayer, RenderService)

The render handler Mapsui invokes for layers tagged with RendererName. Blits the best available image under a translation and schedules an off-thread re-raster when the image no longer covers the viewport.

public static void Render(SKCanvas canvas, Viewport viewport, ILayer layer, RenderService renderService)

Parameters

canvas SKCanvas

viewport Viewport

layer ILayer

renderService RenderService

TryBindFilteredScene(ILayer, ILayer, Func<PaintOp, bool>)

Binds to target a copy of the scene bound to source that keeps only the ops keep accepts — the single-surface counterpart of TryBindFilteredScene(ILayer, ILayer, Func<PaintOp, bool>).

public static bool TryBindFilteredScene(ILayer source, ILayer target, Func<PaintOp, bool> keep)

Parameters

source ILayer

A layer a scene was bound to.

target ILayer

The layer to bind the filtered scene to.

keep Func<PaintOp, bool>

Returns true for each op to keep.

Returns

bool

true when source had a scene to copy.