36881e3770
In order to eventually get rid of SystemJS and start using native `import`s instead, we'll need to provide "complete" file identifiers since otherwise there'll be MIME type errors when attempting to use `import`.
114 lines
3.0 KiB
JavaScript
114 lines
3.0 KiB
JavaScript
/* Copyright 2019 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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/* eslint no-var: error */
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import { ColorSpace } from "./colorspace.js";
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import { JpegStream } from "./jpeg_stream.js";
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import { Stream } from "./stream.js";
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class NativeImageDecoder {
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constructor({
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xref,
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resources,
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handler,
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forceDataSchema = false,
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pdfFunctionFactory,
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}) {
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this.xref = xref;
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this.resources = resources;
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this.handler = handler;
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this.forceDataSchema = forceDataSchema;
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this.pdfFunctionFactory = pdfFunctionFactory;
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}
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canDecode(image) {
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return (
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image instanceof JpegStream &&
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NativeImageDecoder.isDecodable(
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image,
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this.xref,
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this.resources,
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this.pdfFunctionFactory
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)
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);
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}
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decode(image) {
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// For natively supported JPEGs send them to the main thread for decoding.
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const dict = image.dict;
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let colorSpace = dict.get("ColorSpace", "CS");
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colorSpace = ColorSpace.parse(
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colorSpace,
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this.xref,
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this.resources,
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this.pdfFunctionFactory
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);
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return this.handler
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.sendWithPromise("JpegDecode", [
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image.getIR(this.forceDataSchema),
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colorSpace.numComps,
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])
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.then(function({ data, width, height }) {
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return new Stream(data, 0, data.length, dict);
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});
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}
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/**
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* Checks if the image can be decoded and displayed by the browser without any
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* further processing such as color space conversions.
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*/
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static isSupported(image, xref, res, pdfFunctionFactory) {
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const dict = image.dict;
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if (dict.has("DecodeParms") || dict.has("DP")) {
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return false;
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}
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const cs = ColorSpace.parse(
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dict.get("ColorSpace", "CS"),
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xref,
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res,
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pdfFunctionFactory
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);
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// isDefaultDecode() of DeviceGray and DeviceRGB needs no `bpc` argument.
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return (
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(cs.name === "DeviceGray" || cs.name === "DeviceRGB") &&
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cs.isDefaultDecode(dict.getArray("Decode", "D"))
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);
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}
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/**
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* Checks if the image can be decoded by the browser.
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*/
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static isDecodable(image, xref, res, pdfFunctionFactory) {
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const dict = image.dict;
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if (dict.has("DecodeParms") || dict.has("DP")) {
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return false;
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}
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const cs = ColorSpace.parse(
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dict.get("ColorSpace", "CS"),
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xref,
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res,
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pdfFunctionFactory
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);
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const bpc = dict.get("BitsPerComponent", "BPC") || 1;
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return (
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(cs.numComps === 1 || cs.numComps === 3) &&
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cs.isDefaultDecode(dict.getArray("Decode", "D"), bpc)
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);
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}
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}
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export { NativeImageDecoder };
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