72 lines
2.2 KiB
JavaScript
72 lines
2.2 KiB
JavaScript
/* Copyright 2024 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 { BaseException } from "../shared/util.js";
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import OpenJPEG from "../../external/openjpeg/openjpeg.js";
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class JpxError extends BaseException {
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constructor(msg) {
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super(msg, "JpxError");
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}
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}
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class JpxImage {
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static #module = null;
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static decode(data, ignoreColorSpace = false) {
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this.#module ||= OpenJPEG();
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const imageData = this.#module.decode(data, ignoreColorSpace);
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if (typeof imageData === "string") {
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throw new JpxError(imageData);
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}
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return imageData;
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}
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static cleanup() {
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this.#module = null;
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}
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static parseImageProperties(stream) {
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// No need to use OpenJPEG here since we're only getting very basic
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// information which are located in the first bytes of the file.
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let newByte = stream.getByte();
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while (newByte >= 0) {
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const oldByte = newByte;
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newByte = stream.getByte();
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const code = (oldByte << 8) | newByte;
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// Image and tile size (SIZ)
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if (code === 0xff51) {
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stream.skip(4);
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const Xsiz = stream.getInt32() >>> 0; // Byte 4
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const Ysiz = stream.getInt32() >>> 0; // Byte 8
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const XOsiz = stream.getInt32() >>> 0; // Byte 12
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const YOsiz = stream.getInt32() >>> 0; // Byte 16
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stream.skip(16);
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const Csiz = stream.getUint16(); // Byte 36
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return {
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width: Xsiz - XOsiz,
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height: Ysiz - YOsiz,
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// Results are always returned as `Uint8ClampedArray`s.
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bitsPerComponent: 8,
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componentsCount: Csiz,
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};
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}
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}
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throw new JpxError("No size marker found in JPX stream");
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}
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}
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export { JpxError, JpxImage };
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