CMake: minimize dependencies for CHECK_UPDATES=Off, WITH_SCANNER=Off

src/qrcode/utils/QrCodeUtils.cpp

@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// SPDX-FileCopyrightText: 2020-2023 The Monero Project
+
+#include "QrCodeUtils.h"
+#include <QDebug>
+
+bool QrCodeUtils::zimageFromQImage(const QImage &qImg, zbar::Image &dst) {
+    qDebug() << qImg.format();
+    switch (qImg.format()) {
+        case QImage::Format_RGB32 :
+        case QImage::Format_ARGB32 :
+        case QImage::Format_ARGB32_Premultiplied :
+            break;
+        default :
+            return false;
+    }
+
+    unsigned int bpl(qImg.bytesPerLine());
+    unsigned int width(bpl / 4);
+    unsigned int height(qImg.height());
+
+    dst.set_size(width, height);
+    dst.set_format("BGR4");
+    unsigned long datalen = qImg.sizeInBytes();
+    dst.set_data(qImg.bits(), datalen);
+    if ((width * 4 != bpl) || (width * height * 4 > datalen)) {
+        return false;
+    }
+    return true;
+}
+
+QString QrCodeUtils::scanImage(const QImage &img) {
+    zbar::ImageScanner scanner;
+    scanner.set_config(zbar::ZBAR_NONE, zbar::ZBAR_CFG_ENABLE, 1);
+
+    zbar::Image zImg;
+    int r = zimageFromQImage(img, zImg);
+    if (!r) {
+        qWarning() << "Unable to convert QImage into zbar::Image";
+        return "";
+    }
+
+    zbar::Image scanImg = zImg.convert(zbar_fourcc('Y', '8', '0', '0'));
+    scanner.scan(scanImg);
+
+    QString result;
+    for (zbar::Image::SymbolIterator sym = scanImg.symbol_begin(); sym != scanImg.symbol_end(); ++sym) {
+        if (!sym->get_count()) {
+            result = QString::fromStdString(sym->get_data());
+        }
+    }
+    return result;
+}