From 502a429e3e87495dfd93da3cbeb19ca93614c536 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 23 Aug 2024 13:39:32 +0200
Subject: [PATCH 1/2] Use `HTMLCanvasElement.toBlob()` unconditionally in
 `PDFPrintService`

The fallback is very old code, and according to the MDN compatibility data `HTMLCanvasElement.toBlob()` should be available in all browsers that we support now: https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toBlob#browser_compatibility
---
 web/pdf_print_service.js | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/web/pdf_print_service.js b/web/pdf_print_service.js
index 78ea670a7..7017345a0 100644
--- a/web/pdf_print_service.js
+++ b/web/pdf_print_service.js
@@ -190,14 +190,9 @@ class PDFPrintService {
   useRenderedPage() {
     this.throwIfInactive();
     const img = document.createElement("img");
-    const scratchCanvas = this.scratchCanvas;
-    if ("toBlob" in scratchCanvas) {
-      scratchCanvas.toBlob(function (blob) {
-        img.src = URL.createObjectURL(blob);
-      });
-    } else {
-      img.src = scratchCanvas.toDataURL();
-    }
+    this.scratchCanvas.toBlob(blob => {
+      img.src = URL.createObjectURL(blob);
+    });
 
     const wrapper = document.createElement("div");
     wrapper.className = "printedPage";

From 6a1b1ae6a42fcc421d513852b9164be04097b96b Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 23 Aug 2024 18:39:28 +0200
Subject: [PATCH 2/2] Revoke the blob-URLs used during printing in
 `PDFPrintService`

---
 web/pdf_print_service.js | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/web/pdf_print_service.js b/web/pdf_print_service.js
index 7017345a0..45106ca30 100644
--- a/web/pdf_print_service.js
+++ b/web/pdf_print_service.js
@@ -199,10 +199,18 @@ class PDFPrintService {
     wrapper.append(img);
     this.printContainer.append(wrapper);
 
-    return new Promise(function (resolve, reject) {
-      img.onload = resolve;
-      img.onerror = reject;
-    });
+    const { promise, resolve, reject } = Promise.withResolvers();
+    img.onload = resolve;
+    img.onerror = reject;
+
+    promise
+      .catch(() => {
+        // Avoid "Uncaught promise" messages in the console.
+      })
+      .then(() => {
+        URL.revokeObjectURL(img.src);
+      });
+    return promise;
   }
 
   performPrint() {