Merge #14608: qt: Remove the "Pay only required fee..." checkbox

a16f44c04 qt: Remove "Pay only required fee" checkbox (Hennadii Stepanov)
8711cc0c7 qt: Improve BitcoinAmountField class (Hennadii Stepanov)

Pull request description:

  Ref #13280
  This PR removes the "Pay only the required fee..." checkbox from the custom transaction fee section in the "Send" tab. Instead, a minimum value will be enforced on the custom fee input box.

  All comments from #13280 are addressed.

  Before:
  ![screenshot from 2018-10-30 16-42-18](https://user-images.githubusercontent.com/32963518/47726622-866d8e80-dc63-11e8-8670-3f97ff0fa5da.png)

  After:
  ![screenshot from 2018-10-30 16-40-37](https://user-images.githubusercontent.com/32963518/47726633-8f5e6000-dc63-11e8-82cf-5b9ff4aae91d.png)

  cc: @promag @MarcoFalke @Sjors

Tree-SHA512: 073577d38d8353b10e8f36fb52e3c6e81dd45d25d84df9b9e4f78f452ff0bdbff3e225bdd6122b5a03839ffdcc2a2a08175f81c2541cf2d12918536abbfa3fd1

5 files changed, 75 insertions, 81 deletions

diff --git a/src/qt/bitcoinamountfield.cpp b/src/qt/bitcoinamountfield.cpp
index b68f3a439b..558fcf50ba 100644
--- a/src/qt/bitcoinamountfield.cpp
+++ b/src/qt/bitcoinamountfield.cpp
@@ -23,9 +23,7 @@ class AmountSpinBox: public QAbstractSpinBox
 
 public:
     explicit AmountSpinBox(QWidget *parent):
-        QAbstractSpinBox(parent),
-        currentUnit(BitcoinUnits::BTC),
-        singleStep(100000) // satoshis
+        QAbstractSpinBox(parent)
     {
         setAlignment(Qt::AlignRight);
 
@@ -44,10 +42,19 @@ public:
 
     void fixup(QString &input) const
     {
-        bool valid = false;
-        CAmount val = parse(input, &valid);
-        if(valid)
-        {
+        bool valid;
+        CAmount val;
+
+        if (input.isEmpty() && !m_allow_empty) {
+            valid = true;
+            val = m_min_amount;
+        } else {
+            valid = false;
+            val = parse(input, &valid);
+        }
+
+        if (valid) {
+            val = qBound(m_min_amount, val, m_max_amount);
             input = BitcoinUnits::format(currentUnit, val, false, BitcoinUnits::separatorAlways);
             lineEdit()->setText(input);
         }
@@ -64,12 +71,27 @@ public:
         Q_EMIT valueChanged();
     }
 
+    void SetAllowEmpty(bool allow)
+    {
+        m_allow_empty = allow;
+    }
+
+    void SetMinValue(const CAmount& value)
+    {
+        m_min_amount = value;
+    }
+
+    void SetMaxValue(const CAmount& value)
+    {
+        m_max_amount = value;
+    }
+
     void stepBy(int steps)
     {
         bool valid = false;
         CAmount val = value(&valid);
         val = val + steps * singleStep;
-        val = qMin(qMax(val, CAmount(0)), BitcoinUnits::maxMoney());
+        val = qBound(m_min_amount, val, m_max_amount);
         setValue(val);
     }
 
@@ -125,9 +147,12 @@ public:
     }
 
 private:
-    int currentUnit;
-    CAmount singleStep;
+    int currentUnit{BitcoinUnits::BTC};
+    CAmount singleStep{CAmount(100000)}; // satoshis
     mutable QSize cachedMinimumSizeHint;
+    bool m_allow_empty{true};
+    CAmount m_min_amount{CAmount(0)};
+    CAmount m_max_amount{BitcoinUnits::maxMoney()};
 
     /**
      * Parse a string into a number of base monetary units and
@@ -174,11 +199,10 @@ protected:
         StepEnabled rv = 0;
         bool valid = false;
         CAmount val = value(&valid);
-        if(valid)
-        {
-            if(val > 0)
+        if (valid) {
+            if (val > m_min_amount)
                 rv |= StepDownEnabled;
-            if(val < BitcoinUnits::maxMoney())
+            if (val < m_max_amount)
                 rv |= StepUpEnabled;
         }
         return rv;
@@ -275,6 +299,21 @@ void BitcoinAmountField::setValue(const CAmount& value)
     amount->setValue(value);
 }
 
+void BitcoinAmountField::SetAllowEmpty(bool allow)
+{
+    amount->SetAllowEmpty(allow);
+}
+
+void BitcoinAmountField::SetMinValue(const CAmount& value)
+{
+    amount->SetMinValue(value);
+}
+
+void BitcoinAmountField::SetMaxValue(const CAmount& value)
+{
+    amount->SetMaxValue(value);
+}
+
 void BitcoinAmountField::setReadOnly(bool fReadOnly)
 {
     amount->setReadOnly(fReadOnly);
diff --git a/src/qt/bitcoinamountfield.h b/src/qt/bitcoinamountfield.h
index f93579c492..650481e30d 100644
--- a/src/qt/bitcoinamountfield.h
+++ b/src/qt/bitcoinamountfield.h
@@ -31,6 +31,15 @@ public:
     CAmount value(bool *value=0) const;
     void setValue(const CAmount& value);
 
+    /** If allow empty is set to false the field will be set to the minimum allowed value if left empty. **/
+    void SetAllowEmpty(bool allow);
+
+    /** Set the minimum value in satoshis **/
+    void SetMinValue(const CAmount& value);
+
+    /** Set the maximum value in satoshis **/
+    void SetMaxValue(const CAmount& value);
+
     /** Set single step in satoshis **/
     void setSingleStep(const CAmount& step);
 
diff --git a/src/qt/forms/sendcoinsdialog.ui b/src/qt/forms/sendcoinsdialog.ui
index 6b31ddea90..386d559281 100644
--- a/src/qt/forms/sendcoinsdialog.ui
+++ b/src/qt/forms/sendcoinsdialog.ui
@@ -878,28 +878,15 @@ Note:  Since the fee is calculated on a per-byte basis, a fee of "100 satoshis p
                <item>
                 <layout class="QHBoxLayout" name="horizontalLayoutFee8">
                  <item>
-                  <widget class="QCheckBox" name="checkBoxMinimumFee">
-                   <property name="toolTip">
-                    <string>Paying only the minimum fee is just fine as long as there is less transaction volume than space in the blocks. But be aware that this can end up in a never confirming transaction once there is more demand for bitcoin transactions than the network can process.</string>
-                   </property>
-                   <property name="text">
-                    <string/>
-                   </property>
-                  </widget>
-                 </item>
-                 <item>
-                  <widget class="QLabel" name="labelMinFeeWarning">
+                  <widget class="QLabel" name="labelCustomFeeWarning">
                    <property name="enabled">
                     <bool>true</bool>
                    </property>
                    <property name="toolTip">
-                    <string>Paying only the minimum fee is just fine as long as there is less transaction volume than space in the blocks. But be aware that this can end up in a never confirming transaction once there is more demand for bitcoin transactions than the network can process.</string>
+                    <string>When there is less transaction volume than space in the blocks, miners as well as relaying nodes may enforce a minimum fee. Paying only this minimum fee is just fine, but be aware that this can result in a never confirming transaction once there is more demand for bitcoin transactions than the network can process.</string>
                    </property>
                    <property name="text">
-                    <string>(read the tooltip)</string>
-                   </property>
-                   <property name="margin">
-                    <number>5</number>
+                    <string>A too low fee might result in a never confirming transaction (read the tooltip)</string>
                    </property>
                   </widget>
                  </item>
@@ -992,9 +979,6 @@ Note:  Since the fee is calculated on a per-byte basis, a fee of "100 satoshis p
                    <property name="text">
                     <string/>
                    </property>
-                   <property name="margin">
-                    <number>2</number>
-                   </property>
                   </widget>
                  </item>
                  <item>
@@ -1009,9 +993,6 @@ Note:  Since the fee is calculated on a per-byte basis, a fee of "100 satoshis p
                    <property name="text">
                     <string>(Smart fee not initialized yet. This usually takes a few blocks...)</string>
                    </property>
-                   <property name="margin">
-                    <number>2</number>
-                   </property>
                   </widget>
                  </item>
                  <item>
@@ -1038,24 +1019,8 @@ Note:  Since the fee is calculated on a per-byte basis, a fee of "100 satoshis p
                      <property name="text">
                       <string>Confirmation time target:</string>
                      </property>
-                     <property name="margin">
-                      <number>2</number>
-                     </property>
                     </widget>
                    </item>
-                   <item>
-                    <spacer name="verticalSpacer_3">
-                     <property name="orientation">
-                      <enum>Qt::Vertical</enum>
-                     </property>
-                     <property name="sizeHint" stdset="0">
-                      <size>
-                       <width>1</width>
-                       <height>1</height>
-                      </size>
-                     </property>
-                    </spacer>
-                   </item>
                   </layout>
                  </item>
                  <item>
diff --git a/src/qt/sendcoinsdialog.cpp b/src/qt/sendcoinsdialog.cpp
index 858128f9f9..65db0280b7 100644
--- a/src/qt/sendcoinsdialog.cpp
+++ b/src/qt/sendcoinsdialog.cpp
@@ -119,13 +119,11 @@ SendCoinsDialog::SendCoinsDialog(const PlatformStyle *_platformStyle, QWidget *p
         settings.setValue("nSmartFeeSliderPosition", 0);
     if (!settings.contains("nTransactionFee"))
         settings.setValue("nTransactionFee", (qint64)DEFAULT_PAY_TX_FEE);
-    if (!settings.contains("fPayOnlyMinFee"))
-        settings.setValue("fPayOnlyMinFee", false);
     ui->groupFee->setId(ui->radioSmartFee, 0);
     ui->groupFee->setId(ui->radioCustomFee, 1);
     ui->groupFee->button((int)std::max(0, std::min(1, settings.value("nFeeRadio").toInt())))->setChecked(true);
+    ui->customFee->SetAllowEmpty(false);
     ui->customFee->setValue(settings.value("nTransactionFee").toLongLong());
-    ui->checkBoxMinimumFee->setChecked(settings.value("fPayOnlyMinFee").toBool());
     minimizeFeeSection(settings.value("fFeeSectionMinimized").toBool());
 }
 
@@ -174,14 +172,15 @@ void SendCoinsDialog::setModel(WalletModel *_model)
         connect(ui->groupFee, static_cast<void (QButtonGroup::*)(int)>(&QButtonGroup::buttonClicked), this, &SendCoinsDialog::updateFeeSectionControls);
         connect(ui->groupFee, static_cast<void (QButtonGroup::*)(int)>(&QButtonGroup::buttonClicked), this, &SendCoinsDialog::coinControlUpdateLabels);
         connect(ui->customFee, &BitcoinAmountField::valueChanged, this, &SendCoinsDialog::coinControlUpdateLabels);
-        connect(ui->checkBoxMinimumFee, &QCheckBox::stateChanged, this, &SendCoinsDialog::setMinimumFee);
-        connect(ui->checkBoxMinimumFee, &QCheckBox::stateChanged, this, &SendCoinsDialog::updateFeeSectionControls);
-        connect(ui->checkBoxMinimumFee, &QCheckBox::stateChanged, this, &SendCoinsDialog::coinControlUpdateLabels);
         connect(ui->optInRBF, &QCheckBox::stateChanged, this, &SendCoinsDialog::updateSmartFeeLabel);
         connect(ui->optInRBF, &QCheckBox::stateChanged, this, &SendCoinsDialog::coinControlUpdateLabels);
-        ui->customFee->setSingleStep(model->wallet().getRequiredFee(1000));
+        CAmount requiredFee = model->wallet().getRequiredFee(1000);
+        ui->customFee->SetMinValue(requiredFee);
+        if (ui->customFee->value() < requiredFee) {
+            ui->customFee->setValue(requiredFee);
+        }
+        ui->customFee->setSingleStep(requiredFee);
         updateFeeSectionControls();
-        updateMinFeeLabel();
         updateSmartFeeLabel();
 
         // set default rbf checkbox state
@@ -210,7 +209,6 @@ SendCoinsDialog::~SendCoinsDialog()
     settings.setValue("nFeeRadio", ui->groupFee->checkedId());
     settings.setValue("nConfTarget", getConfTargetForIndex(ui->confTargetSelector->currentIndex()));
     settings.setValue("nTransactionFee", (qint64)ui->customFee->value());
-    settings.setValue("fPayOnlyMinFee", ui->checkBoxMinimumFee->isChecked());
 
     delete ui;
 }
@@ -542,7 +540,6 @@ void SendCoinsDialog::updateDisplayUnit()
 {
     setBalance(model->wallet().getBalances());
     ui->customFee->setDisplayUnit(model->getOptionsModel()->getDisplayUnit());
-    updateMinFeeLabel();
     updateSmartFeeLabel();
 }
 
@@ -642,11 +639,6 @@ void SendCoinsDialog::useAvailableBalance(SendCoinsEntry* entry)
     }
 }
 
-void SendCoinsDialog::setMinimumFee()
-{
-    ui->customFee->setValue(model->wallet().getRequiredFee(1000));
-}
-
 void SendCoinsDialog::updateFeeSectionControls()
 {
     ui->confTargetSelector      ->setEnabled(ui->radioSmartFee->isChecked());
@@ -654,10 +646,9 @@ void SendCoinsDialog::updateFeeSectionControls()
     ui->labelSmartFee2          ->setEnabled(ui->radioSmartFee->isChecked());
     ui->labelSmartFee3          ->setEnabled(ui->radioSmartFee->isChecked());
     ui->labelFeeEstimation      ->setEnabled(ui->radioSmartFee->isChecked());
-    ui->checkBoxMinimumFee      ->setEnabled(ui->radioCustomFee->isChecked());
-    ui->labelMinFeeWarning      ->setEnabled(ui->radioCustomFee->isChecked());
-    ui->labelCustomPerKilobyte  ->setEnabled(ui->radioCustomFee->isChecked() && !ui->checkBoxMinimumFee->isChecked());
-    ui->customFee               ->setEnabled(ui->radioCustomFee->isChecked() && !ui->checkBoxMinimumFee->isChecked());
+    ui->labelCustomFeeWarning   ->setEnabled(ui->radioCustomFee->isChecked());
+    ui->labelCustomPerKilobyte  ->setEnabled(ui->radioCustomFee->isChecked());
+    ui->customFee               ->setEnabled(ui->radioCustomFee->isChecked());
 }
 
 void SendCoinsDialog::updateFeeMinimizedLabel()
@@ -672,14 +663,6 @@ void SendCoinsDialog::updateFeeMinimizedLabel()
     }
 }
 
-void SendCoinsDialog::updateMinFeeLabel()
-{
-    if (model && model->getOptionsModel())
-        ui->checkBoxMinimumFee->setText(tr("Pay only the required fee of %1").arg(
-            BitcoinUnits::formatWithUnit(model->getOptionsModel()->getDisplayUnit(), model->wallet().getRequiredFee(1000)) + "/kB")
-        );
-}
-
 void SendCoinsDialog::updateCoinControlState(CCoinControl& ctrl)
 {
     if (ui->radioCustomFee->isChecked()) {
diff --git a/src/qt/sendcoinsdialog.h b/src/qt/sendcoinsdialog.h
index 7009855f17..e1ebc77d59 100644
--- a/src/qt/sendcoinsdialog.h
+++ b/src/qt/sendcoinsdialog.h
@@ -92,9 +92,7 @@ private Q_SLOTS:
     void coinControlClipboardBytes();
     void coinControlClipboardLowOutput();
     void coinControlClipboardChange();
-    void setMinimumFee();
     void updateFeeSectionControls();
-    void updateMinFeeLabel();
     void updateSmartFeeLabel();
 
 Q_SIGNALS: