From f731222b3f5566b131d1613756e7a6435de8f87c Mon Sep 17 00:00:00 2001
From: trbKnl <ncdeschipper@gmail.com>
Date: Tue, 20 Feb 2024 10:18:06 +0100
Subject: [PATCH] links clickable in pdfs from pdf.js

---
 core/assets/js/pdf_viewer.js | 58 +++++++++++++++++++++++++++++-------
 1 file changed, 47 insertions(+), 11 deletions(-)

diff --git a/core/assets/js/pdf_viewer.js b/core/assets/js/pdf_viewer.js
index 5d398910a7..a10be28d92 100644
--- a/core/assets/js/pdf_viewer.js
+++ b/core/assets/js/pdf_viewer.js
@@ -47,21 +47,55 @@ export const PDFViewer = {
   renderPage(width, pageNum) {
     console.log("[PDFViewer] Render page", pageNum);
     this.pdf.getPage(pageNum).then(
-      (page) => {
-        var canvas = this.createCanvas();
+      async (page) => {
+        var scale = window.devicePixelRatio;
+        var viewport = page.getViewport({ scale: scale });
+        if (width < viewport.width) {
+          scale = (width / viewport.width) * scale;
+        }
+
+        //This gives us the page's dimensions at full scale
+        viewport = page.getViewport({ scale: scale });
+
+        //We'll create a canvas for each page to draw it on
+        const canvas = this.createCanvas(viewport);
         const context = canvas.getContext("2d");
+        page.render({ canvasContext: context, viewport: viewport });
 
-        const pdfWidth = page.getViewport({ scale: 1 }).width;
-        const viewport = page.getViewport({ scale: width / pdfWidth });
+        // Make annotations clickable
+        const annotations = await page.getAnnotations()
 
-        console.log("[PDFViewer] width", width);
-        console.log("[PDFViewer] pdfWidth", pdfWidth);
-        console.log("[PDFViewer] viewport.width", viewport.width);
+        function translateEventCoordinatesToPdfViewport(canvas, x ,y) {
+          const rect = canvas.getBoundingClientRect();
+          const newx = (x - rect.left) / scale;
+          const newy = (-1 * (y - rect.bottom)) / scale;
+          return {x: newx, y: newy}
+        }
 
-        canvas.width = viewport.width;
-        canvas.height = viewport.height;
+        canvas.addEventListener("click", (event) => {
+          const {x, y} = translateEventCoordinatesToPdfViewport(canvas, event.clientX, event.clientY)
+          for (let annotation of annotations) {
+            const rect  = annotation.rect
+            if (x > rect[0] && x < rect[2] && y > rect[1] && y < rect[3]) {
+              if (annotation.url) {
+                window.open(annotation.url, "_blank");
+              }
+            }
+          }
+        });
 
-        page.render({ canvasContext: context, viewport: viewport });
+        canvas.addEventListener("mousemove", (event) => {
+          const {x, y} = translateEventCoordinatesToPdfViewport(canvas, event.clientX, event.clientY)
+          for (let annotation of annotations) {
+            const rect  = annotation.rect
+            if (x > rect[0] && x < rect[2] && y > rect[1] && y < rect[3]) {
+              canvas.style.cursor = "pointer"
+              break
+            } else {
+              canvas.style.cursor = "default"
+            }
+          }
+        })
 
         this.renderPage(width, pageNum + 1);
       },
@@ -79,9 +113,11 @@ export const PDFViewer = {
     this.container.style.display = "block";
     this.el.appendChild(this.container);
   },
-  createCanvas() {
+  createCanvas(viewport) {
     var canvas = document.createElement("canvas");
     canvas.style.display = "block";
+    canvas.height = viewport.height;
+    canvas.width = viewport.width;
     this.container.appendChild(canvas);
     return canvas;
   },