59c4041a49
This patch also changes most examples to use "top level await", since that's now supported and slightly simplifies the code.
60 lines
1.8 KiB
JavaScript
60 lines
1.8 KiB
JavaScript
/* Copyright 2018 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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if (!pdfjsImageDecoders.JpegImage) {
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// eslint-disable-next-line no-alert
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alert("Please build the pdfjs-dist library using `gulp dist-install`");
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}
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const JPEG_IMAGE = "fish.jpg";
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const jpegCanvas = document.getElementById("jpegCanvas");
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const jpegCtx = jpegCanvas.getContext("2d");
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// Load the image data, and convert it to a Uint8Array.
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//
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const response = await fetch(JPEG_IMAGE);
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if (!response.ok) {
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throw new Error(response.statusText);
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}
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const typedArrayImage = new Uint8Array(await response.arrayBuffer());
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// Parse the image data using `JpegImage`.
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//
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const jpegImage = new pdfjsImageDecoders.JpegImage();
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jpegImage.parse(typedArrayImage);
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const width = jpegImage.width,
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height = jpegImage.height;
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const jpegData = jpegImage.getData({
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width,
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height,
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forceRGB: true,
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});
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// Render the JPEG image on a <canvas>.
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//
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const imageData = jpegCtx.createImageData(width, height);
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const imageBytes = imageData.data;
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for (let j = 0, k = 0, jj = width * height * 4; j < jj; ) {
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imageBytes[j++] = jpegData[k++];
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imageBytes[j++] = jpegData[k++];
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imageBytes[j++] = jpegData[k++];
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imageBytes[j++] = 255;
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}
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jpegCanvas.width = width;
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jpegCanvas.height = height;
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jpegCtx.putImageData(imageData, 0, 0);
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