feat: move qr code glue in MSALoginDialog (#3676)

launcher/CMakeLists.txt

@@ -1311,7 +1311,7 @@ target_link_libraries(Launcher_logic
     qdcss
     BuildConfig
     Qt${QT_VERSION_MAJOR}::Widgets
-    qrcode
+    qrcodegenerator
 )
 
 if (UNIX AND NOT CYGWIN AND NOT APPLE)

launcher/ui/dialogs/MSALoginDialog.cpp

@@ -36,7 +36,6 @@
 #include "MSALoginDialog.h"
 #include "Application.h"
 
-#include "qr.h"
 #include "ui_MSALoginDialog.h"
 
 #include "DesktopServices.h"
@@ -44,10 +43,15 @@
 
 #include <QApplication>
 #include <QClipboard>
+#include <QColor>
+#include <QPainter>
 #include <QPixmap>
+#include <QSize>
 #include <QUrl>
 #include <QtWidgets/QPushButton>
 
+#include "qrcodegen.hpp"
+
 MSALoginDialog::MSALoginDialog(QWidget* parent) : QDialog(parent), ui(new Ui::MSALoginDialog)
 {
     ui->setupUi(this);
@@ -139,6 +143,33 @@ void MSALoginDialog::authorizeWithBrowser(const QUrl& url)
     m_url = url;
 }
 
+// https://stackoverflow.com/questions/21400254/how-to-draw-a-qr-code-with-qt-in-native-c-c
+void paintQR(QPainter& painter, const QSize sz, const QString& data, QColor fg)
+{
+    // NOTE: At this point you will use the API to get the encoding and format you want, instead of my hardcoded stuff:
+    qrcodegen::QrCode qr = qrcodegen::QrCode::encodeText(data.toUtf8().constData(), qrcodegen::QrCode::Ecc::LOW);
+    const int s = qr.getSize() > 0 ? qr.getSize() : 1;
+    const double w = sz.width();
+    const double h = sz.height();
+    const double aspect = w / h;
+    const double size = ((aspect > 1.0) ? h : w);
+    const double scale = size / (s + 2);
+    // NOTE: For performance reasons my implementation only draws the foreground parts in supplied color.
+    // It expects background to be prepared already (in white or whatever is preferred).
+    painter.setPen(Qt::NoPen);
+    painter.setBrush(fg);
+    for (int y = 0; y < s; y++) {
+        for (int x = 0; x < s; x++) {
+            const int color = qr.getModule(x, y);  // 0 for white, 1 for black
+            if (0 != color) {
+                const double rx1 = (x + 1) * scale, ry1 = (y + 1) * scale;
+                QRectF r(rx1, ry1, scale, scale);
+                painter.drawRects(&r, 1);
+            }
+        }
+    }
+}
+
 void MSALoginDialog::authorizeWithBrowserWithExtra(QString url, QString code, [[maybe_unused]] int expiresIn)
 {
     ui->stackedWidget->setCurrentIndex(1);