/* global pdfjsLib */
// https://github.com/mozilla/pdf.js/blob/f04967017f22e46d70d11468dd928b4cdc2f6ea1/web/text_layer_builder.css
const textLayerBuilderCSS = `
/* Copyright 2014 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
:root {
--highlight-bg-color: rgb(180 0 170);
--highlight-selected-bg-color: rgb(0 100 0);
}
@media screen and (forced-colors: active) {
:root {
--highlight-bg-color: Highlight;
--highlight-selected-bg-color: ButtonText;
}
}
.textLayer {
position: absolute;
text-align: initial;
inset: 0;
overflow: hidden;
opacity: 0.25;
line-height: 1;
text-size-adjust: none;
forced-color-adjust: none;
transform-origin: 0 0;
z-index: 2;
}
.textLayer :is(span, br) {
color: transparent;
position: absolute;
white-space: pre;
cursor: text;
transform-origin: 0% 0%;
}
/* Only necessary in Google Chrome, see issue 14205, and most unfortunately
* the problem doesn't show up in "text" reference tests. */
/*#if !MOZCENTRAL*/
.textLayer span.markedContent {
top: 0;
height: 0;
}
/*#endif*/
.textLayer .highlight {
margin: -1px;
padding: 1px;
background-color: var(--highlight-bg-color);
border-radius: 4px;
}
.textLayer .highlight.appended {
position: initial;
}
.textLayer .highlight.begin {
border-radius: 4px 0 0 4px;
}
.textLayer .highlight.end {
border-radius: 0 4px 4px 0;
}
.textLayer .highlight.middle {
border-radius: 0;
}
.textLayer .highlight.selected {
background-color: var(--highlight-selected-bg-color);
}
.textLayer ::selection {
/*#if !MOZCENTRAL*/
background: blue;
/*#endif*/
background: AccentColor; /* stylelint-disable-line declaration-block-no-duplicate-properties */
}
/* Avoids https://github.com/mozilla/pdf.js/issues/13840 in Chrome */
/*#if !MOZCENTRAL*/
.textLayer br::selection {
background: transparent;
}
/*#endif*/
.textLayer .endOfContent {
display: block;
position: absolute;
inset: 100% 0 0;
z-index: -1;
cursor: default;
user-select: none;
}
.textLayer .endOfContent.active {
top: 0;
}
`
const renderPage = async (page, getImageBlob) => {
const scale = devicePixelRatio
const viewport = page.getViewport({ scale })
const canvas = document.createElement('canvas')
canvas.height = viewport.height
canvas.width = viewport.width
const canvasContext = canvas.getContext('2d')
await page.render({ canvasContext, viewport }).promise
const blob = await new Promise(resolve => canvas.toBlob(resolve))
if (getImageBlob) return blob
/*
// with the SVG backend
const operatorList = await page.getOperatorList()
const svgGraphics = new pdfjsLib.SVGGraphics(page.commonObjs, page.objs)
const svg = await svgGraphics.getSVG(operatorList, viewport)
const str = new XMLSerializer().serializeToString(svg)
const blob = new Blob([str], { type: 'image/svg+xml' })
*/
const container = document.createElement('div')
container.classList.add('textLayer')
await pdfjsLib.renderTextLayer({
textContentSource: await page.getTextContent(),
container, viewport,
}).promise
const src = URL.createObjectURL(blob)
const url = URL.createObjectURL(new Blob([`
${container.outerHTML}
`], { type: 'text/html' }))
return url
}
const makeTOCItem = item => ({
label: item.title,
href: JSON.stringify(item.dest),
subitems: item.items.length ? item.items.map(makeTOCItem) : null,
})
export const makePDF = async file => {
const data = new Uint8Array(await file.arrayBuffer())
const pdf = await pdfjsLib.getDocument({ data }).promise
const book = { rendition: { layout: 'pre-paginated' } }
const info = (await pdf.getMetadata())?.info
book.metadata = {
title: info?.Title,
author: info?.Author,
}
const outline = await pdf.getOutline()
book.toc = outline?.map(makeTOCItem)
const cache = new Map()
book.sections = Array.from({ length: pdf.numPages }).map((_, i) => ({
id: i,
load: async () => {
const cached = cache.get(i)
if (cached) return cached
const url = await renderPage(await pdf.getPage(i + 1))
cache.set(i, url)
return url
},
size: 1000,
}))
book.resolveHref = async href => {
const parsed = JSON.parse(href)
const dest = typeof parsed === 'string'
? await pdf.getDestination(parsed) : parsed
const index = await pdf.getPageIndex(dest[0])
return { index }
}
book.splitTOCHref = async href => {
const parsed = JSON.parse(href)
const dest = typeof parsed === 'string'
? await pdf.getDestination(parsed) : parsed
const index = await pdf.getPageIndex(dest[0])
return [index, null]
}
book.getTOCFragment = doc => doc.documentElement
book.getCover = async () => renderPage(await pdf.getPage(1), true)
return book
}