phd student, middle child
Published
Edited
Sep 24, 2020
1 fork
2 stars
import { HTTPFileChunkStore } from '@manzt/zarr-js-file-chunk-store'
chunkstore = await fetch(url + '.zchunkstore').then(res => res.json())
pyramid = {
// Init store
const chunkstore = await fetch(url + '.zchunkstore').then(res => res.json());
const store = new HTTPFileChunkStore(url, chunkstore);
// get pyramidal paths
const rootAttrs = await getJson(store, '.zattrs');
const { datasets } = rootAttrs.multiscales[0];
return Promise.all(
datasets.map(({ path }) => zarr.openArray({ store, path }))
);
}
draw_scan(pyramid[4])
async function draw_scan(z_arr, channels = [0, 1, 3]) {
// Fetch the 2D pixel arrays for each channel
const [r, g, b] = await Promise.all(
channels.map(c => z_arr.getRaw([c, null, null]))
);
// Need to interleave the channels in RGBA buffer...
const rgba = new Uint8ClampedArray(4 * r.data.length).fill(0);
let offset = 0;
for (let i = 0; i < r.data.length; i++) {
rgba[offset] = r.data[i];
rgba[offset + 1] = g.data[i];
rgba[offset + 2] = b.data[i];
rgba[offset + 3] = 255; // alpha
offset += 4;
}
// Create image and draw to canvas
const img = new ImageData(rgba, z_arr.shape[2], z_arr.shape[1]);
const context = DOM.context2d(img.width / 2, img.height / 2);
context.putImageData(img, 0, 0);
return context.canvas;
}
zarr = import('zarr@0.3')
import { table } from '@tmcw/tables'
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