|
| 1 | +'use client'; |
| 2 | + |
| 3 | +import React, {useState, useRef, useEffect} from 'react'; |
| 4 | +import {Document, Page, pdfjs} from 'react-pdf'; |
| 5 | +import 'react-pdf/dist/Page/TextLayer.css'; |
| 6 | +import 'react-pdf/dist/Page/AnnotationLayer.css'; |
| 7 | + |
| 8 | +pdfjs.GlobalWorkerOptions.workerSrc = `//cdnjs.cloudflare.com/ajax/libs/pdf.js/${pdfjs.version}/pdf.worker.js`; |
| 9 | + |
| 10 | +const MyPdfViewer = () => { |
| 11 | + const [file, setFile] = useState<File | null>(null); |
| 12 | + const [numPages, setNumPages] = useState<number | null>(null); |
| 13 | + // eslint-disable-next-line @typescript-eslint/no-unused-vars |
| 14 | + const [pageNumber, setPageNumber] = useState<number>(1); |
| 15 | + const [inputValue, setInputValue] = useState<string>('1'); |
| 16 | + const pageRefs = useRef<(React.RefObject<HTMLDivElement> | null)[]>([]); |
| 17 | + |
| 18 | + // PDFファイルが読み込まれたときの処理 |
| 19 | + function onDocumentLoadSuccess({numPages}: {numPages: number}) { |
| 20 | + setNumPages(numPages); |
| 21 | + pageRefs.current = Array(numPages) |
| 22 | + .fill(null) |
| 23 | + .map(() => React.createRef()); |
| 24 | + } |
| 25 | + |
| 26 | + // ファイルを選択したときの処理 |
| 27 | + const handleChange = (event: React.ChangeEvent<HTMLInputElement>) => { |
| 28 | + const file = event.target.files?.[0]; |
| 29 | + if (file) { |
| 30 | + const reader = new FileReader(); |
| 31 | + reader.onload = () => { |
| 32 | + setFile(file); |
| 33 | + }; |
| 34 | + reader.readAsDataURL(file); |
| 35 | + } |
| 36 | + }; |
| 37 | + |
| 38 | + // ページが表示されたときの処理 |
| 39 | + const observePage = (pageIndex: number) => { |
| 40 | + const observer = new IntersectionObserver( |
| 41 | + entries => { |
| 42 | + if (entries[0].isIntersecting) { |
| 43 | + setPageNumber(pageIndex + 1); |
| 44 | + setInputValue((pageIndex + 1).toString()); |
| 45 | + } |
| 46 | + }, |
| 47 | + {threshold: 0.5} |
| 48 | + ); |
| 49 | + |
| 50 | + // ページが表示されたときにページ番号を更新する |
| 51 | + const pageElement = pageRefs.current[pageIndex]?.current; |
| 52 | + if (pageElement) { |
| 53 | + observer.observe(pageElement); |
| 54 | + } |
| 55 | + return () => { |
| 56 | + if (pageElement) { |
| 57 | + observer.unobserve(pageElement); |
| 58 | + } |
| 59 | + }; |
| 60 | + }; |
| 61 | + |
| 62 | + // ページ番号を指定してページに移動する |
| 63 | + const goToPage = (page: number) => { |
| 64 | + const pageElement = pageRefs.current[page - 1]?.current; |
| 65 | + if (pageElement) { |
| 66 | + pageElement.scrollIntoView(); |
| 67 | + } |
| 68 | + }; |
| 69 | + |
| 70 | + // ページ数が変わったときにページの表示を監視する |
| 71 | + useEffect(() => { |
| 72 | + const cleanupFunctions = Array(numPages || 0) |
| 73 | + .fill(null) |
| 74 | + .map((_, index) => observePage(index)); |
| 75 | + return () => { |
| 76 | + cleanupFunctions.forEach(cleanup => cleanup()); |
| 77 | + }; |
| 78 | + }, [numPages]); |
| 79 | + |
| 80 | + return ( |
| 81 | + <div> |
| 82 | + <input type="file" onChange={handleChange} /> |
| 83 | + {file && ( |
| 84 | + <div> |
| 85 | + <div> |
| 86 | + <label>Page: </label> |
| 87 | + <input |
| 88 | + type="text" |
| 89 | + value={inputValue} |
| 90 | + onChange={e => setInputValue(e.target.value)} |
| 91 | + onKeyDown={e => { |
| 92 | + if (e.key === 'Enter') { |
| 93 | + goToPage(Number(inputValue)); |
| 94 | + } |
| 95 | + }} |
| 96 | + className="border rounded p-1 w-10 text-center" |
| 97 | + /> |
| 98 | + / {numPages} |
| 99 | + </div> |
| 100 | + <div className="h-[80vh] overflow-auto"> |
| 101 | + <Document file={file as File} onLoadSuccess={onDocumentLoadSuccess}> |
| 102 | + {Array.from(new Array(numPages || 0), (el, index) => ( |
| 103 | + <Page |
| 104 | + key={`page_${index + 1}`} |
| 105 | + pageNumber={index + 1} |
| 106 | + inputRef={pageRefs.current[index]} |
| 107 | + /> |
| 108 | + ))} |
| 109 | + </Document> |
| 110 | + </div> |
| 111 | + </div> |
| 112 | + )} |
| 113 | + </div> |
| 114 | + ); |
| 115 | +}; |
| 116 | + |
| 117 | +export default MyPdfViewer; |
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