From 4f321563c7d2df7a621ea7912779753bdd774a2d Mon Sep 17 00:00:00 2001
From: John Factotum <50942278+johnfactotum@users.noreply.github.com>
Date: Mon, 9 Oct 2023 01:56:13 +0800
Subject: [PATCH] PDF: add annotation layer and handle links

---
 pdf.js | 392 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 392 insertions(+)

diff --git a/pdf.js b/pdf.js
index fd88184..bcadc11 100644
--- a/pdf.js
+++ b/pdf.js
@@ -114,6 +114,385 @@ const textLayerBuilderCSS = `
 }
 `
 
+//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 scale = devicePixelRatio
     const viewport = page.getViewport({ scale })
@@ -142,6 +521,16 @@ const renderPage = async (page, getImageBlob) => {
         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>
@@ -155,9 +544,11 @@ const renderPage = async (page, getImageBlob) => {
             padding: 0;
         }
         ${textLayerBuilderCSS}
+        ${annotationLayerBuilderCSS}
         </style>
         <img src="${src}">
         ${container.outerHTML}
+        ${div.outerHTML}
     `], { type: 'text/html' }))
     return url
 }
@@ -195,6 +586,7 @@ export const makePDF = async file => {
         },
         size: 1000,
     }))
+    book.isExternal = uri => /^\w+:/i.test(uri)
     book.resolveHref = async href => {
         const parsed = JSON.parse(href)
         const dest = typeof parsed === 'string'