Add QR code display on the receive page

This embeds MIT licenced code from Project Nayuki:
https://www.nayuki.io/page/qr-code-generator-library
The C++ part of the code is embedded in src/QR-Code-generator.
See src/QR-Code-generator/Readme.markdown for more info.

2 files changed, 28 insertions, 0 deletions

diff --git a/src/libwalletqt/QRCodeImageProvider.cpp b/src/libwalletqt/QRCodeImageProvider.cpp
new file mode 100644
index 00000000..217d3d7d
--- /dev/null
+++ b/src/libwalletqt/QRCodeImageProvider.cpp
@@ -0,0 +1,17 @@
+#include "QrCode.hpp"
+
+#include "QRCodeImageProvider.h"
+
+QImage QRCodeImageProvider::requestImage(const QString &id, QSize *size, const QSize &requestedSize)
+{
+  using namespace qrcodegen;
+
+  QrCode qrcode = QrCode::encodeText(id.toStdString().c_str(), QrCode::Ecc::MEDIUM);
+  QImage img = QImage(qrcode.size, qrcode.size, QImage::Format_Mono);
+  for (int y = 0; y < qrcode.size; ++y)
+    for (int x = 0; x < qrcode.size; ++x)
+      img.setPixel(x, y, qrcode.getModule(x, y));
+  if (size)
+    *size = QSize(qrcode.size, qrcode.size);
+  return img;
+}
diff --git a/src/libwalletqt/QRCodeImageProvider.h b/src/libwalletqt/QRCodeImageProvider.h
new file mode 100644
index 00000000..930b731a
--- /dev/null
+++ b/src/libwalletqt/QRCodeImageProvider.h
@@ -0,0 +1,11 @@
+#include <QImage>
+#include <QQuickImageProvider>
+
+class QRCodeImageProvider: public QQuickImageProvider
+{
+public:
+  QRCodeImageProvider(): QQuickImageProvider(QQuickImageProvider::Image) {}
+
+  QImage requestImage(const QString &id, QSize *size, const QSize &requestedSize);
+};
+