Add address label to request payment QR Code (QT)

In the Receive 'Tab' of the QT wallet, when 'Show'ing a previously requested payment, add a label underneath the QR Code showing the bitcoin address where the funds will go to.

This way the user can be sure that the QR code scanner app the user using is reading the correct bitcoin address, preventing funds to be stolen.

Includes fix for HiDPI screens by @jonasschnelli.

1 files changed, 17 insertions, 5 deletions

diff --git a/src/qt/receiverequestdialog.cpp b/src/qt/receiverequestdialog.cpp
index a1e9156eea..b13ea3df70 100644
--- a/src/qt/receiverequestdialog.cpp
+++ b/src/qt/receiverequestdialog.cpp
@@ -45,7 +45,7 @@ QImage QRImageWidget::exportImage()
 {
     if(!pixmap())
         return QImage();
-    return pixmap()->toImage().scaled(EXPORT_IMAGE_SIZE, EXPORT_IMAGE_SIZE);
+    return pixmap()->toImage();
 }
 
 void QRImageWidget::mousePressEvent(QMouseEvent *event)
@@ -166,20 +166,32 @@ void ReceiveRequestDialog::update()
                 ui->lblQRCode->setText(tr("Error encoding URI into QR Code."));
                 return;
             }
-            QImage myImage = QImage(code->width + 8, code->width + 8, QImage::Format_RGB32);
-            myImage.fill(0xffffff);
+            QImage qrImage = QImage(code->width + 8, code->width + 8, QImage::Format_RGB32);
+            qrImage.fill(0xffffff);
             unsigned char *p = code->data;
             for (int y = 0; y < code->width; y++)
             {
                 for (int x = 0; x < code->width; x++)
                 {
-                    myImage.setPixel(x + 4, y + 4, ((*p & 1) ? 0x0 : 0xffffff));
+                    qrImage.setPixel(x + 4, y + 4, ((*p & 1) ? 0x0 : 0xffffff));
                     p++;
                 }
             }
             QRcode_free(code);
 
-            ui->lblQRCode->setPixmap(QPixmap::fromImage(myImage).scaled(300, 300));
+            QImage qrAddrImage = QImage(QR_IMAGE_SIZE, QR_IMAGE_SIZE+20, QImage::Format_RGB32);
+            qrAddrImage.fill(0xffffff);
+            QPainter painter(&qrAddrImage);
+            painter.drawImage(0, 0, qrImage.scaled(QR_IMAGE_SIZE, QR_IMAGE_SIZE));
+            QFont font = GUIUtil::fixedPitchFont();
+            font.setPixelSize(12);
+            painter.setFont(font);
+            QRect paddedRect = qrAddrImage.rect();
+            paddedRect.setHeight(QR_IMAGE_SIZE+12);
+            painter.drawText(paddedRect, Qt::AlignBottom|Qt::AlignCenter, info.address);
+            painter.end();
+
+            ui->lblQRCode->setPixmap(QPixmap::fromImage(qrAddrImage));
             ui->btnSaveAs->setEnabled(true);
         }
     }