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.
132 lines
2.9 KiB
JavaScript
132 lines
2.9 KiB
JavaScript
/* Copyright 2021 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 { bytesToString, shadow, unreachable } from "../shared/util.js";
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class BaseStream {
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constructor() {
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if (this.constructor === BaseStream) {
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unreachable("Cannot initialize BaseStream.");
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}
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}
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// eslint-disable-next-line getter-return
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get length() {
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unreachable("Abstract getter `length` accessed");
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}
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// eslint-disable-next-line getter-return
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get isEmpty() {
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unreachable("Abstract getter `isEmpty` accessed");
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}
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get isDataLoaded() {
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return shadow(this, "isDataLoaded", true);
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}
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getByte() {
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unreachable("Abstract method `getByte` called");
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}
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getBytes(length) {
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unreachable("Abstract method `getBytes` called");
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}
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/**
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* NOTE: This method can only be used to get image-data that is guaranteed
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* to be fully loaded, since otherwise intermittent errors may occur;
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* note the `ObjectLoader` class.
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*/
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async getImageData(length, decoderOptions) {
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return this.getBytes(length, decoderOptions);
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}
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async asyncGetBytes() {
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unreachable("Abstract method `asyncGetBytes` called");
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}
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get isAsync() {
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return false;
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}
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get canAsyncDecodeImageFromBuffer() {
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return false;
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}
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peekByte() {
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const peekedByte = this.getByte();
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if (peekedByte !== -1) {
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this.pos--;
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}
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return peekedByte;
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}
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peekBytes(length) {
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const bytes = this.getBytes(length);
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this.pos -= bytes.length;
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return bytes;
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}
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getUint16() {
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const b0 = this.getByte();
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const b1 = this.getByte();
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if (b0 === -1 || b1 === -1) {
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return -1;
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}
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return (b0 << 8) + b1;
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}
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getInt32() {
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const b0 = this.getByte();
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const b1 = this.getByte();
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const b2 = this.getByte();
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const b3 = this.getByte();
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return (b0 << 24) + (b1 << 16) + (b2 << 8) + b3;
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}
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getByteRange(begin, end) {
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unreachable("Abstract method `getByteRange` called");
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}
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getString(length) {
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return bytesToString(this.getBytes(length));
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}
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skip(n) {
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this.pos += n || 1;
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}
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reset() {
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unreachable("Abstract method `reset` called");
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}
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moveStart() {
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unreachable("Abstract method `moveStart` called");
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}
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makeSubStream(start, length, dict = null) {
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unreachable("Abstract method `makeSubStream` called");
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}
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/**
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* @returns {Array | null}
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*/
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getBaseStreams() {
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return null;
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}
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}
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export { BaseStream };
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