pdf.js

/* 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;
}
`

//https://github.com/mozilla/pdf.js/blob/d64f223d034ad74fb62571c3acff566d25eca413/web/annotation_layer_builder.css
const annotationLayerBuilderCSS = `
/* 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 {
  --annotation-unfocused-field-background: url("data:image/svg+xml;charset=UTF-8,<svg width='1px' height='1px' xmlns='http://www.w3.org/2000/svg'><rect width='100%' height='100%' style='fill:rgba(0, 54, 255, 0.13);'/></svg>");
  --input-focus-border-color: Highlight;
  --input-focus-outline: 1px solid Canvas;
  --input-unfocused-border-color: transparent;
  --input-disabled-border-color: transparent;
  --input-hover-border-color: black;
  --link-outline: none;
}

@media screen and (forced-colors: active) {
  :root {
    --input-focus-border-color: CanvasText;
    --input-unfocused-border-color: ActiveText;
    --input-disabled-border-color: GrayText;
    --input-hover-border-color: Highlight;
    --link-outline: 1.5px solid LinkText;
    --hcm-highligh-filter: invert(100%);
  }
  .annotationLayer .textWidgetAnnotation :is(input, textarea):required,
  .annotationLayer .choiceWidgetAnnotation select:required,
  .annotationLayer
    .buttonWidgetAnnotation:is(.checkBox, .radioButton)
    input:required {
    outline: 1.5px solid selectedItem;
  }

  .annotationLayer .linkAnnotation:hover {
    backdrop-filter: var(--hcm-highligh-filter);
  }

  .annotationLayer .linkAnnotation > a:hover {
    opacity: 0 !important;
    background: none !important;
    box-shadow: none;
  }

  .annotationLayer .popupAnnotation .popup {
    outline: calc(1.5px * var(--scale-factor)) solid CanvasText !important;
    background-color: ButtonFace !important;
    color: ButtonText !important;
  }

  .annotationLayer .highlightArea:hover::after {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    backdrop-filter: var(--hcm-highligh-filter);
    content: "";
    pointer-events: none;
  }

  .annotationLayer .popupAnnotation.focused .popup {
    outline: calc(3px * var(--scale-factor)) solid Highlight !important;
  }
}

.annotationLayer {
  position: absolute;
  top: 0;
  left: 0;
  pointer-events: none;
  transform-origin: 0 0;
  z-index: 3;
}

.annotationLayer[data-main-rotation="90"] .norotate {
  transform: rotate(270deg) translateX(-100%);
}
.annotationLayer[data-main-rotation="180"] .norotate {
  transform: rotate(180deg) translate(-100%, -100%);
}
.annotationLayer[data-main-rotation="270"] .norotate {
  transform: rotate(90deg) translateY(-100%);
}

.annotationLayer canvas {
  position: absolute;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.annotationLayer section {
  position: absolute;
  text-align: initial;
  pointer-events: auto;
  box-sizing: border-box;
  transform-origin: 0 0;
}

.annotationLayer .linkAnnotation {
  outline: var(--link-outline);
}

.annotationLayer :is(.linkAnnotation, .buttonWidgetAnnotation.pushButton) > a {
  position: absolute;
  font-size: 1em;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

.annotationLayer
  :is(.linkAnnotation, .buttonWidgetAnnotation.pushButton):not(.hasBorder)
  > a:hover {
  opacity: 0.2;
  background-color: rgb(255 255 0);
  box-shadow: 0 2px 10px rgb(255 255 0);
}

.annotationLayer .linkAnnotation.hasBorder:hover {
  background-color: rgb(255 255 0 / 0.2);
}

.annotationLayer .hasBorder {
  background-size: 100% 100%;
}

.annotationLayer .textAnnotation img {
  position: absolute;
  cursor: pointer;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
}

.annotationLayer .textWidgetAnnotation :is(input, textarea),
.annotationLayer .choiceWidgetAnnotation select,
.annotationLayer .buttonWidgetAnnotation:is(.checkBox, .radioButton) input {
  background-image: var(--annotation-unfocused-field-background);
  border: 2px solid var(--input-unfocused-border-color);
  box-sizing: border-box;
  font: calc(9px * var(--scale-factor)) sans-serif;
  height: 100%;
  margin: 0;
  vertical-align: top;
  width: 100%;
}

.annotationLayer .textWidgetAnnotation :is(input, textarea):required,
.annotationLayer .choiceWidgetAnnotation select:required,
.annotationLayer
  .buttonWidgetAnnotation:is(.checkBox, .radioButton)
  input:required {
  outline: 1.5px solid red;
}

.annotationLayer .choiceWidgetAnnotation select option {
  padding: 0;
}

.annotationLayer .buttonWidgetAnnotation.radioButton input {
  border-radius: 50%;
}

.annotationLayer .textWidgetAnnotation textarea {
  resize: none;
}

.annotationLayer .textWidgetAnnotation :is(input, textarea)[disabled],
.annotationLayer .choiceWidgetAnnotation select[disabled],
.annotationLayer
  .buttonWidgetAnnotation:is(.checkBox, .radioButton)
  input[disabled] {
  background: none;
  border: 2px solid var(--input-disabled-border-color);
  cursor: not-allowed;
}

.annotationLayer .textWidgetAnnotation :is(input, textarea):hover,
.annotationLayer .choiceWidgetAnnotation select:hover,
.annotationLayer
  .buttonWidgetAnnotation:is(.checkBox, .radioButton)
  input:hover {
  border: 2px solid var(--input-hover-border-color);
}
.annotationLayer .textWidgetAnnotation :is(input, textarea):hover,
.annotationLayer .choiceWidgetAnnotation select:hover,
.annotationLayer .buttonWidgetAnnotation.checkBox input:hover {
  border-radius: 2px;
}

.annotationLayer .textWidgetAnnotation :is(input, textarea):focus,
.annotationLayer .choiceWidgetAnnotation select:focus {
  background: none;
  border: 2px solid var(--input-focus-border-color);
  border-radius: 2px;
  outline: var(--input-focus-outline);
}

.annotationLayer .buttonWidgetAnnotation:is(.checkBox, .radioButton) :focus {
  background-image: none;
  background-color: transparent;
}

.annotationLayer .buttonWidgetAnnotation.checkBox :focus {
  border: 2px solid var(--input-focus-border-color);
  border-radius: 2px;
  outline: var(--input-focus-outline);
}

.annotationLayer .buttonWidgetAnnotation.radioButton :focus {
  border: 2px solid var(--input-focus-border-color);
  outline: var(--input-focus-outline);
}

.annotationLayer .buttonWidgetAnnotation.checkBox input:checked::before,
.annotationLayer .buttonWidgetAnnotation.checkBox input:checked::after,
.annotationLayer .buttonWidgetAnnotation.radioButton input:checked::before {
  background-color: CanvasText;
  content: "";
  display: block;
  position: absolute;
}

.annotationLayer .buttonWidgetAnnotation.checkBox input:checked::before,
.annotationLayer .buttonWidgetAnnotation.checkBox input:checked::after {
  height: 80%;
  left: 45%;
  width: 1px;
}

.annotationLayer .buttonWidgetAnnotation.checkBox input:checked::before {
  transform: rotate(45deg);
}

.annotationLayer .buttonWidgetAnnotation.checkBox input:checked::after {
  transform: rotate(-45deg);
}

.annotationLayer .buttonWidgetAnnotation.radioButton input:checked::before {
  border-radius: 50%;
  height: 50%;
  left: 30%;
  top: 20%;
  width: 50%;
}

.annotationLayer .textWidgetAnnotation input.comb {
  font-family: monospace;
  padding-left: 2px;
  padding-right: 0;
}

.annotationLayer .textWidgetAnnotation input.comb:focus {
  /*
   * Letter spacing is placed on the right side of each character. Hence, the
   * letter spacing of the last character may be placed outside the visible
   * area, causing horizontal scrolling. We avoid this by extending the width
   * when the element has focus and revert this when it loses focus.
   */
  width: 103%;
}

.annotationLayer .buttonWidgetAnnotation:is(.checkBox, .radioButton) input {
  appearance: none;
}

.annotationLayer .fileAttachmentAnnotation .popupTriggerArea {
  height: 100%;
  width: 100%;
}

.annotationLayer .popupAnnotation {
  position: absolute;
  font-size: calc(9px * var(--scale-factor));
  pointer-events: none;
  width: max-content;
  max-width: 45%;
  height: auto;
}

.annotationLayer .popup {
  background-color: rgb(255 255 153);
  box-shadow: 0 calc(2px * var(--scale-factor)) calc(5px * var(--scale-factor))
    rgb(136 136 136);
  border-radius: calc(2px * var(--scale-factor));
  outline: 1.5px solid rgb(255 255 74);
  padding: calc(6px * var(--scale-factor));
  cursor: pointer;
  font: message-box;
  white-space: normal;
  word-wrap: break-word;
  pointer-events: auto;
}

.annotationLayer .popupAnnotation.focused .popup {
  outline-width: 3px;
}

.annotationLayer .popup * {
  font-size: calc(9px * var(--scale-factor));
}

.annotationLayer .popup > .header {
  display: inline-block;
}

.annotationLayer .popup > .header h1 {
  display: inline;
}

.annotationLayer .popup > .header .popupDate {
  display: inline-block;
  margin-left: calc(5px * var(--scale-factor));
  width: fit-content;
}

.annotationLayer .popupContent {
  border-top: 1px solid rgb(51 51 51);
  margin-top: calc(2px * var(--scale-factor));
  padding-top: calc(2px * var(--scale-factor));
}

.annotationLayer .richText > * {
  white-space: pre-wrap;
  font-size: calc(9px * var(--scale-factor));
}

.annotationLayer .popupTriggerArea {
  cursor: pointer;
}

.annotationLayer section svg {
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
}

.annotationLayer .annotationTextContent {
  position: absolute;
  width: 100%;
  height: 100%;
  opacity: 0;
  color: transparent;
  user-select: none;
  pointer-events: none;
}

.annotationLayer .annotationTextContent span {
  width: 100%;
  display: inline-block;
}

.annotationLayer svg.quadrilateralsContainer {
  contain: strict;
  width: 0;
  height: 0;
  position: absolute;
  top: 0;
  left: 0;
  z-index: -1;
}
`

const renderPage = async (page, getImageBlob) => {

    const naturalPdfSize = page.getViewport({ scale: 1 })
    const naturalPdfRatio = naturalPdfSize.width / naturalPdfSize.height
    const appRatio = innerWidth / innerHeight
    const pdfToAppResolutionRatio = appRatio / naturalPdfRatio

    const scale = devicePixelRatio * pdfToAppResolutionRatio
    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 div = document.createElement('div')
    div.classList.add('annotationLayer')
    await new pdfjsLib.AnnotationLayer({ page, viewport, div }).render({
        annotations: await page.getAnnotations(),
        linkService: {
            getDestinationHash: dest => JSON.stringify(dest),
            addLinkAttributes: (link, url) => link.href = url,
        },
    })

    const src = URL.createObjectURL(blob)
    const url = URL.createObjectURL(new Blob([`
        <!DOCTYPE html>
        <meta charset="utf-8">
        <style>
        :root {
            --scale-factor: ${scale};
        }
        html, body {
            margin: 0;
            padding: 0;
        }
        ${textLayerBuilderCSS}
        ${annotationLayerBuilderCSS}
        </style>
        <img src="${src}">
        ${container.outerHTML}
        ${div.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.sections[0].pageSpread = 'right'
    book.isExternal = uri => /^\w+:/i.test(uri)
    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
}