From 72516c311bd4ae39604cbc4b1903e0e97b882602 Mon Sep 17 00:00:00 2001
From: Marijn Besseling <njirambem@gmail.com>
Date: Wed, 10 Sep 2025 21:12:51 +0200
Subject: add qr pages

---
 Blog/Components/Pages/QRCodeScan.razor.js | 100 ++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 Blog/Components/Pages/QRCodeScan.razor.js

(limited to 'Blog/Components/Pages/QRCodeScan.razor.js')

diff --git a/Blog/Components/Pages/QRCodeScan.razor.js b/Blog/Components/Pages/QRCodeScan.razor.js
new file mode 100644
index 0000000..bb80f37
--- /dev/null
+++ b/Blog/Components/Pages/QRCodeScan.razor.js
@@ -0,0 +1,100 @@
+import { getById, writeError, writeInfo, a, div } from "/common.module.js";
+
+// regexr.com/2rj36
+const url_like_regex =
+    /^[-a-zA-Z0-9@:%_\+.~#?&//=]{2,256}\.[a-z]{2,4}\b(\/[-a-zA-Z0-9@:%_\+.~#?&//=]*)?$/i;
+
+///https://stackoverflow.com/questions/3115982/how-to-check-if-two-arrays-are-equal-with-javascript
+function arraysEqual(a, b) {
+    if (a === b) return true;
+    if (a == null || b == null) return false;
+    if (a.length !== b.length) return false;
+
+    for (var i = 0; i < a.length; ++i) {
+        if (a[i] !== b[i]) return false;
+    }
+    return true;
+}
+
+function logQRValue(value) {
+    if (URL.canParse(value)) {
+        writeInfo(div(a(new URL(url).href, value)));
+    } else if (url_like_regex.test(value)) {
+        // Not a true URL but close enough for me to create an anchor tag.
+        if (!value.startsWith("http://") && !value.startsWith("https://")) {
+            value = "https://" + value;
+        }
+        writeInfo(div(a(value, value)));
+    } else {
+        writeInfo(value);
+    }
+}
+
+export function onLoad() {
+    // check compatibility
+    if (!("BarcodeDetector" in globalThis)) {
+        writeError(
+            "Barcode Detector is not supported by this browser. Make sure Shape Detection API is turned on.",
+        );
+    } else {
+        writeInfo("Barcode Detector supported!");
+
+        // create new detector
+        const barcodeDetector = new BarcodeDetector({
+            formats: ["qr_code"],
+        });
+
+        const initBarcodescan = (stream) => {
+            writeInfo("Starting scanner...");
+            var lastbarcodes = [];
+            setInterval(() => {
+                barcodeDetector
+                    .detect(stream)
+                    .then((barcodes) => {
+                        if (barcodes.length === 0) {
+                        } else {
+                            const values = barcodes.map(
+                                (barcode) => barcode.rawValue,
+                            );
+                            if (arraysEqual(values, lastbarcodes)) {
+                                return;
+                            }
+
+                            values.forEach(logQRValue);
+                            lastbarcodes = values;
+                        }
+                    })
+                    .catch((err) => {
+                        writeError(err);
+                    });
+            }, 1000);
+        };
+
+        var video = getById("video");
+        video.setAttribute("playsinline", "");
+        video.setAttribute("autoplay", "");
+        video.setAttribute("muted", "");
+        video.style.width = "100%";
+        // video.style.height = "100%";
+
+        /* Setting up the constraint */
+        var facingMode = "environment"; // Can be 'user' or 'environment' to access back or front camera (NEAT!)
+        var constraints = {
+            audio: false,
+            video: {
+                facingMode: facingMode,
+            },
+        };
+
+        /* Stream it to video element */
+        navigator.mediaDevices
+            .getUserMedia(constraints)
+            .then(function success(stream) {
+                video.srcObject = stream;
+            })
+            .finally(() => {
+                writeInfo("Initialized video stream");
+                initBarcodescan(video);
+            });
+    }
+}
\ No newline at end of file
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