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196affd8e0
When an image has a non-zero SMaskInData it means that the image has an alpha channel. With JPX images, the colorspace isn't required (by spec) so when we don't have it, the JPX decoder will handle the conversion in RGBA format.
80 lines
2.5 KiB
JavaScript
80 lines
2.5 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, warn } from "../shared/util.js";
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import OpenJPEG from "../../external/openjpeg/openjpeg.js";
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import { Stream } from "./stream.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, decoderOptions) {
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decoderOptions ||= {};
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this.#module ||= OpenJPEG({ warn });
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const imageData = this.#module.decode(data, decoderOptions);
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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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if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("IMAGE_DECODERS")) {
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if (stream instanceof ArrayBuffer || ArrayBuffer.isView(stream)) {
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stream = new Stream(stream);
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} else {
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throw new JpxError("Invalid data format, must be a TypedArray.");
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}
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}
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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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