32 lines
1.1 KiB
JavaScript
32 lines
1.1 KiB
JavaScript
import { createCanvasSurface } from '../core/canvas_surface.js';
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const MAX_STATIC_LAYERS = 24;
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export function createStaticLayerCanvas(width, height) {
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return createCanvasSurface(width, height)?.canvas || null;
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}
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export function drawCachedStaticLayer(state, g, layerId, key, rect, build) {
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if (!state || !rect || rect.w <= 0 || rect.h <= 0) return;
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if (!state.staticLayers) state.staticLayers = new Map();
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const fullKey = `${layerId}:${key}:${Math.max(0, rect.w | 0)}x${Math.max(0, rect.h | 0)}`;
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let layer = state.staticLayers.get(fullKey);
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if (layer) {
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// Map-Reihenfolge als kleine LRU-Liste verwenden.
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state.staticLayers.delete(fullKey);
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state.staticLayers.set(fullKey, layer);
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}
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if (!layer) {
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const canvas = createStaticLayerCanvas(rect.w, rect.h);
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if (!canvas) return;
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const ctx = canvas.getContext('2d');
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build(ctx, rect);
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layer = { canvas };
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state.staticLayers.set(fullKey, layer);
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while (state.staticLayers.size > MAX_STATIC_LAYERS) {
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state.staticLayers.delete(state.staticLayers.keys().next().value);
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}
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}
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g.drawImage(layer.canvas, rect.x, rect.y);
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}
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