fb0775525e
For all of the other `DecodeStream`s we're not passing in a `Dict`-instance manually, but instead get it from the `stream`-parameter. Hence there's no particularly good reason, as far as I can tell, to not do the same thing in `Jbig2Stream`/`JpegStream`/`JpxStream` as well.
88 lines
2.7 KiB
JavaScript
88 lines
2.7 KiB
JavaScript
/* Copyright 2012 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 { DecodeStream } from "./decode_stream.js";
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import { JpxImage } from "./jpx.js";
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import { shadow } from "../shared/util.js";
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/**
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* For JPEG 2000's we use a library to decode these images and
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* the stream behaves like all the other DecodeStreams.
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*/
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class JpxStream extends DecodeStream {
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constructor(stream, maybeLength, params) {
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super(maybeLength);
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this.stream = stream;
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this.dict = stream.dict;
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this.maybeLength = maybeLength;
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this.params = params;
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}
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get bytes() {
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// If `this.maybeLength` is null, we'll get the entire stream.
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return shadow(this, "bytes", this.stream.getBytes(this.maybeLength));
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}
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ensureBuffer(requested) {
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// No-op, since `this.readBlock` will always parse the entire image and
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// directly insert all of its data into `this.buffer`.
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}
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readBlock() {
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if (this.eof) {
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return;
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}
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const jpxImage = new JpxImage();
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jpxImage.parse(this.bytes);
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const width = jpxImage.width;
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const height = jpxImage.height;
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const componentsCount = jpxImage.componentsCount;
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const tileCount = jpxImage.tiles.length;
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if (tileCount === 1) {
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this.buffer = jpxImage.tiles[0].items;
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} else {
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const data = new Uint8ClampedArray(width * height * componentsCount);
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for (let k = 0; k < tileCount; k++) {
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const tileComponents = jpxImage.tiles[k];
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const tileWidth = tileComponents.width;
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const tileHeight = tileComponents.height;
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const tileLeft = tileComponents.left;
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const tileTop = tileComponents.top;
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const src = tileComponents.items;
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let srcPosition = 0;
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let dataPosition = (width * tileTop + tileLeft) * componentsCount;
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const imgRowSize = width * componentsCount;
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const tileRowSize = tileWidth * componentsCount;
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for (let j = 0; j < tileHeight; j++) {
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const rowBytes = src.subarray(srcPosition, srcPosition + tileRowSize);
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data.set(rowBytes, dataPosition);
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srcPosition += tileRowSize;
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dataPosition += imgRowSize;
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}
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}
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this.buffer = data;
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}
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this.bufferLength = this.buffer.length;
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this.eof = true;
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}
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}
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export { JpxStream };
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