50 lines
1.5 KiB
JavaScript
50 lines
1.5 KiB
JavaScript
import DataTile from '../../../../src/ol/source/DataTile.js';
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import Map from '../../../../src/ol/Map.js';
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import TileLayer from '../../../../src/ol/layer/WebGLTile.js';
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import View from '../../../../src/ol/View.js';
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const size = [81, 99];
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const canvas = document.createElement('canvas');
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canvas.width = size[0];
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canvas.height = size[1];
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const context = canvas.getContext('2d');
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context.strokeStyle = 'white';
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context.textAlign = 'center';
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const lineHeight = 16;
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context.font = `${lineHeight}px sans-serif`;
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new Map({
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target: 'map',
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layers: [
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new TileLayer({
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source: new DataTile({
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loader: function (z, x, y) {
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const halfWidth = size[0] / 2;
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const halfHeight = size[1] / 2;
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context.fillStyle = '#00AAFF';
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context.fillRect(0, 0, size[0], size[1]);
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context.fillStyle = 'white';
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context.fillText(`z: ${z}`, halfWidth, halfHeight - lineHeight);
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context.fillText(`x: ${x}`, halfWidth, halfHeight);
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context.fillText(`y: ${y}`, halfWidth, halfHeight + lineHeight);
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context.strokeRect(0, 0, size[0], size[1]);
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const data = context.getImageData(0, 0, size[0], size[1]).data;
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const bandCount = 3;
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const result = data.filter((_, index) => index % 4 < bandCount);
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return Promise.resolve(result);
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},
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tileSize: size,
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}),
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}),
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],
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view: new View({
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center: [0, 0],
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zoom: 4,
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}),
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});
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render({tolerance: 0.03});
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