GUI: Enable customisation of QR Code font

Author: luke-jr

src/qt/forms/optionsdialog.ui

@@ -796,6 +796,31 @@
          </item>
         </layout>
        </item>
+       <item>
+        <layout class="QHBoxLayout" name="horizontalLayout_qrFont">
+         <item>
+          <widget class="QLabel" name="qrFontLabel">
+           <property name="text">
+            <string>Font in QR Codes: </string>
+           </property>
+           <property name="buddy">
+            <cstring>qrFont</cstring>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <widget class="QComboBox" name="qrFont"/>
+         </item>
+         <item>
+          <widget class="QLabel" name="qrFont_preview">
+           <property name="text">
+            <string notr="true">1NS17iag9jJgT…
+bc1p2q3rvn3gp…</string>
+           </property>
+          </widget>
+         </item>
+        </layout>
+       </item>
        <item>
         <spacer name="verticalSpacer_Display">
          <property name="orientation">

src/qt/optionsdialog.cpp

@@ -205,6 +205,12 @@ OptionsDialog::OptionsDialog(QWidget* parent, bool enableWallet)
     }
 
     setupFontOptions(ui->moneyFont, ui->moneyFont_preview);
+    setupFontOptions(ui->qrFont, ui->qrFont_preview);
+#ifndef USE_QRCODE
+    ui->qrFontLabel->setVisible(false);
+    ui->qrFont->setVisible(false);
+    ui->qrFont_preview->setVisible(false);
+#endif
 
     GUIUtil::handleCloseWindowShortcut(this);
 }
@@ -245,6 +251,9 @@ void OptionsDialog::setModel(OptionsModel *_model)
         const auto& font_for_money = _model->data(_model->index(OptionsModel::FontForMoney, 0), Qt::EditRole).value<OptionsModel::FontChoice>();
         setFontChoice(ui->moneyFont, font_for_money);
 
+        const auto& font_for_qrcodes = _model->data(_model->index(OptionsModel::FontForQRCodes, 0), Qt::EditRole).value<OptionsModel::FontChoice>();
+        setFontChoice(ui->qrFont, font_for_qrcodes);
+
         updateDefaultProxyNets();
     }
 
@@ -384,6 +393,7 @@ void OptionsDialog::on_openBitcoinConfButton_clicked()
 void OptionsDialog::on_okButton_clicked()
 {
     model->setData(model->index(OptionsModel::FontForMoney, 0), ui->moneyFont->itemData(ui->moneyFont->currentIndex()));
+    model->setData(model->index(OptionsModel::FontForQRCodes, 0), ui->qrFont->itemData(ui->qrFont->currentIndex()));
 
     mapper->submit();
     accept();

src/qt/optionsmodel.cpp

@@ -258,6 +258,11 @@ bool OptionsModel::Init(bilingual_str& error)
     }
     Q_EMIT fontForMoneyChanged(getFontForMoney());
 
+    if (settings.contains("FontForQRCodes")) {
+        m_font_qrcodes = FontChoiceFromString(settings.value("FontForQRCodes").toString());
+    }
+    Q_EMIT fontForQRCodesChanged(getFontChoiceForQRCodes());
+
     m_mask_values = settings.value("mask_values", false).toBool();
 
     return true;
@@ -466,6 +471,8 @@ QVariant OptionsModel::getOption(OptionID option, const std::string& suffix) con
         return QString::fromStdString(SettingToString(setting(), ""));
     case FontForMoney:
         return QVariant::fromValue(m_font_money);
+    case FontForQRCodes:
+        return QVariant::fromValue(m_font_qrcodes);
     case CoinControlFeatures:
         return fCoinControlFeatures;
     case EnablePSBTControls:
@@ -649,6 +656,15 @@ bool OptionsModel::setOption(OptionID option, const QVariant& value, const std::
         Q_EMIT fontForMoneyChanged(getFontForMoney());
         break;
     }
+    case FontForQRCodes:
+    {
+        const auto& new_font = value.value<FontChoice>();
+        if (m_font_qrcodes == new_font) break;
+        settings.setValue("FontForQRCodes", FontChoiceToString(new_font));
+        m_font_qrcodes = new_font;
+        Q_EMIT fontForQRCodesChanged(new_font);
+        break;
+    }
     case CoinControlFeatures:
         fCoinControlFeatures = value.toBool();
         settings.setValue("fCoinControlFeatures", fCoinControlFeatures);

src/qt/optionsmodel.h

@@ -63,6 +63,7 @@ class OptionsModel : public QAbstractListModel
         ThirdPartyTxUrls,       // QString
         Language,               // QString
         FontForMoney,           // FontChoice
+        FontForQRCodes,         // FontChoice
         CoinControlFeatures,    // bool
         SubFeeFromAmount,       // bool
         ThreadsScriptVerif,     // int
@@ -104,6 +105,7 @@ class OptionsModel : public QAbstractListModel
     BitcoinUnit getDisplayUnit() const { return m_display_bitcoin_unit; }
     QString getThirdPartyTxUrls() const { return strThirdPartyTxUrls; }
     QFont getFontForMoney() const;
+    FontChoice getFontChoiceForQRCodes() const { return m_font_qrcodes; }
     bool getCoinControlFeatures() const { return fCoinControlFeatures; }
     bool getSubFeeFromAmount() const { return m_sub_fee_from_amount; }
     bool getEnablePSBTControls() const { return m_enable_psbt_controls; }
@@ -131,6 +133,7 @@ class OptionsModel : public QAbstractListModel
     BitcoinUnit m_display_bitcoin_unit;
     QString strThirdPartyTxUrls;
     FontChoice m_font_money{FontChoiceAbstract::EmbeddedFont};
+    FontChoice m_font_qrcodes{FontChoiceAbstract::BestSystemFont};
     bool fCoinControlFeatures;
     bool m_sub_fee_from_amount;
     bool m_enable_psbt_controls;
@@ -153,6 +156,7 @@ class OptionsModel : public QAbstractListModel
     void coinControlFeaturesChanged(bool);
     void showTrayIconChanged(bool);
     void fontForMoneyChanged(const QFont&);
+    void fontForQRCodesChanged(const FontChoice&);
 };
 
 Q_DECLARE_METATYPE(OptionsModel::FontChoice)

src/qt/qrimagewidget.cpp

@@ -5,6 +5,7 @@
 #include <qt/qrimagewidget.h>
 
 #include <qt/guiutil.h>
+#include <qt/optionsmodel.h>
 
 #include <QApplication>
 #include <QClipboard>
@@ -31,7 +32,7 @@ QRImageWidget::QRImageWidget(QWidget* parent)
     contextMenu->addAction(tr("&Copy Image"), this, &QRImageWidget::copyImage);
 }
 
-bool QRImageWidget::setQR(const QString& data, const QString& text)
+bool QRImageWidget::setQR(const QString& data, const QString& text, const OptionsModel::FontChoice& fontchoice)
 {
 #ifdef USE_QRCODE
     setText("");
@@ -72,11 +73,22 @@ bool QRImageWidget::setQR(const QString& data, const QString& text)
             QRect paddedRect = qrAddrImage.rect();
             paddedRect.setHeight(QR_IMAGE_SIZE + QR_IMAGE_TEXT_MARGIN);
 
-            QFont font = GUIUtil::fixedPitchFont();
-            font.setStretch(QFont::SemiCondensed);
-            font.setLetterSpacing(QFont::AbsoluteSpacing, 1);
-            const qreal font_size = GUIUtil::calculateIdealFontSize(paddedRect.width() - 2 * QR_IMAGE_TEXT_MARGIN, text, font);
-            font.setPointSizeF(font_size);
+            QFont font;
+
+            // Determine font to use
+            if (std::holds_alternative<OptionsModel::FontChoiceAbstract>(fontchoice)) {
+                font = GUIUtil::fixedPitchFont(fontchoice != OptionsModel::UseBestSystemFont);
+                font.setWeight(QFont::Bold);
+                font.setStretch(QFont::SemiCondensed);
+                font.setLetterSpacing(QFont::AbsoluteSpacing, 1);
+
+                const auto qr_image_width = paddedRect.width();
+                const int max_text_width = qr_image_width - (2 * QR_IMAGE_TEXT_MARGIN);
+                const qreal font_size = GUIUtil::calculateIdealFontSize(max_text_width, text, font);
+                font.setPointSizeF(font_size);
+            } else {
+                font = std::get<QFont>(fontchoice);
+            }
 
             painter.setFont(font);
             painter.drawText(paddedRect, Qt::AlignBottom | Qt::AlignCenter, text);
@@ -92,6 +104,11 @@ bool QRImageWidget::setQR(const QString& data, const QString& text)
 #endif
 }
 
+bool QRImageWidget::setQR(const QString& data)
+{
+    return setQR(data, "", OptionsModel::FontChoiceAbstract::EmbeddedFont);
+}
+
 QImage QRImageWidget::exportImage()
 {
     return GUIUtil::GetImage(this);

src/qt/qrimagewidget.h

@@ -5,6 +5,8 @@
 #ifndef BITCOIN_QT_QRIMAGEWIDGET_H
 #define BITCOIN_QT_QRIMAGEWIDGET_H
 
+#include <qt/optionsmodel.h>
+
 #include <QImage>
 #include <QLabel>
 
@@ -29,7 +31,8 @@ class QRImageWidget : public QLabel
 
 public:
     explicit QRImageWidget(QWidget *parent = nullptr);
-    bool setQR(const QString& data, const QString& text = "");
+    bool setQR(const QString& data);
+    bool setQR(const QString& data, const QString& text, const OptionsModel::FontChoice& fontchoice);
     QImage exportImage();
 
 public Q_SLOTS:

src/qt/receiverequestdialog.cpp

@@ -49,8 +49,11 @@ void ReceiveRequestDialog::setInfo(const SendCoinsRecipient &_info)
     QString uri = GUIUtil::formatBitcoinURI(info);
 
 #ifdef USE_QRCODE
-    if (ui->qr_code->setQR(uri, info.address)) {
+    if (ui->qr_code->setQR(uri, info.address, model->getOptionsModel()->getFontChoiceForQRCodes())) {
         connect(ui->btnSaveAs, &QPushButton::clicked, ui->qr_code, &QRImageWidget::saveImage);
+        connect(model->getOptionsModel(), &OptionsModel::fontForQRCodesChanged, this, [&](const OptionsModel::FontChoice& fontchoice){
+            ui->qr_code->setQR(uri, info.address, fontchoice);
+        });
     } else {
         ui->btnSaveAs->setEnabled(false);
     }