79 lines
2.9 KiB
JavaScript
79 lines
2.9 KiB
JavaScript
/* Copyright 2017 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import { createImage } from "../../src/core/editor/pdf_images.js";
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import { Dict } from "../../src/core/primitives.js";
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import { FlateStream } from "../../src/core/flate_stream.js";
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import { isNodeJS } from "../../src/shared/util.js";
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import { PredictorStream } from "../../src/core/predictor_stream.js";
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import { Stream } from "../../src/core/stream.js";
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describe("stream", function () {
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describe("PredictorStream", function () {
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it("should decode simple predictor data", function () {
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const dict = new Dict();
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dict.set("Predictor", 12);
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dict.set("Colors", 1);
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dict.set("BitsPerComponent", 8);
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dict.set("Columns", 2);
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const input = new Stream(
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new Uint8Array([2, 100, 3, 2, 1, 255, 2, 1, 255]),
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0,
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9,
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dict
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);
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const predictor = new PredictorStream(input, /* length = */ 9, dict);
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const result = predictor.getBytes(6);
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expect(result).toEqual(new Uint8Array([100, 3, 101, 2, 102, 1]));
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});
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it("should decode the FlateDecode stream produced by createImage", async function () {
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if (isNodeJS) {
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pending("OffscreenCanvas is not supported in Node.js.");
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}
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const width = 2;
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const height = 2;
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const canvas = new OffscreenCanvas(width, height);
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const ctx = canvas.getContext("2d");
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const source = new Uint8ClampedArray([
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255, 0, 0, 255, 0, 255, 0, 255, 0, 0, 255, 255, 255, 255, 0, 255,
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]);
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ctx.putImageData(new ImageData(source, width, height), 0, 0);
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const bitmap = canvas.transferToImageBitmap();
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const { imageStream } = await createImage(bitmap, /* xref = */ null, {
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closeBitmap: true,
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});
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expect(imageStream.dict.get("Filter").name).toEqual("FlateDecode");
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const flate = new FlateStream(imageStream, imageStream.length);
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const predictor = new PredictorStream(
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flate,
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imageStream.length,
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imageStream.dict.get("DecodeParms")
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);
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const decoded = predictor.getBytes(width * height * 3);
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const expected = new Uint8Array(width * height * 3);
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for (let i = 0, j = 0; i < source.length; i += 4, j += 3) {
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expected[j] = source[i];
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expected[j + 1] = source[i + 1];
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expected[j + 2] = source[i + 2];
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}
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expect(decoded).toEqual(expected);
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});
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});
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});
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