toggle fee rate selection on send, dont show zero total rate series

src/main/java/com/sparrowwallet/sparrow/control/MempoolSizeFeeRatesChart.java

@@ -6,7 +6,6 @@ import com.sparrowwallet.sparrow.wallet.SendController;
 import javafx.application.Platform;
 import javafx.beans.NamedArg;
 import javafx.collections.FXCollections;
-import javafx.geometry.Pos;
 import javafx.scene.Cursor;
 import javafx.scene.Node;
 import javafx.scene.chart.*;
@@ -67,6 +66,7 @@ public class MempoolSizeFeeRatesChart extends StackedAreaChart<String, Number> {
         }
 
         categoryAxis.setGapStartAndEnd(false);
+        categoryAxis.setTickLabelRotation(0);
         categoryAxis.setOnMouseMoved(mouseEvent -> {
             String category = categoryAxis.getValueForDisplay(mouseEvent.getX());
             if(category != null) {
@@ -92,6 +92,7 @@ public class MempoolSizeFeeRatesChart extends StackedAreaChart<String, Number> {
         for(Long feeRate : SendController.FEE_RATES_RANGE) {
             XYChart.Series<String, Number> series = new XYChart.Series<>();
             series.setName(feeRate + "+ vB");
+            long seriesTotalVSize = 0;
 
             for(Date date : periodRateSizes.keySet()) {
                 Set<MempoolRateSize> rateSizes = periodRateSizes.get(date);
@@ -103,10 +104,14 @@ public class MempoolSizeFeeRatesChart extends StackedAreaChart<String, Number> {
                 }
 
                 series.getData().add(new XYChart.Data<>(dateFormatter.format(date), totalVSize));
+                seriesTotalVSize += totalVSize;
+            }
+
+            if(seriesTotalVSize > 0) {
+                getData().add(series);
             }
 
             previousFeeRate = feeRate;
-            getData().add(series);
         }
 
         if(categories.iterator().hasNext()) {

src/main/java/com/sparrowwallet/sparrow/wallet/SendController.java

@@ -55,6 +55,15 @@ public class SendController extends WalletFormController implements Initializabl
     @FXML
     private TabPane paymentTabs;
 
+    @FXML
+    private ToggleGroup feeSelectionToggleGroup;
+
+    @FXML
+    private ToggleButton targetBlocksToggle;
+
+    @FXML
+    private ToggleButton mempoolSizeToggle;
+
     @FXML
     private Field targetBlocksField;
 
@@ -260,7 +269,14 @@ public class SendController extends WalletFormController implements Initializabl
             mempoolSizeFeeRatesChart.update(mempoolHistogram);
         }
 
-        updateFeeRateSelection(Config.get().getFeeRateSelection());
+        FeeRateSelection feeRateSelection = Config.get().getFeeRateSelection();
+        updateFeeRateSelection(feeRateSelection);
+        feeSelectionToggleGroup.selectToggle(feeRateSelection == FeeRateSelection.BLOCK_TARGET ? targetBlocksToggle : mempoolSizeToggle);
+        feeSelectionToggleGroup.selectedToggleProperty().addListener((observable, oldValue, newValue) -> {
+            FeeRateSelection newFeeRateSelection = (FeeRateSelection)newValue.getUserData();
+            Config.get().setFeeRateSelection(newFeeRateSelection);
+            EventManager.get().post(new FeeRateSelectionChangedEvent(newFeeRateSelection));
+        });
 
         fee.setTextFormatter(new CoinTextFormatter());
         fee.textProperty().addListener(feeListener);

src/main/resources/com/sparrowwallet/sparrow/wallet/send.fxml

@@ -22,10 +22,12 @@
 <?import com.sparrowwallet.sparrow.control.FiatLabel?>
 <?import org.controlsfx.glyphfont.Glyph?>
 <?import com.sparrowwallet.sparrow.control.MempoolSizeFeeRatesChart?>
+<?import org.controlsfx.control.SegmentedButton?>
+<?import com.sparrowwallet.sparrow.wallet.FeeRateSelection?>
 
 <BorderPane stylesheets="@send.css, @wallet.css, @../script.css, @../general.css" styleClass="wallet-pane" xmlns="http://javafx.com/javafx/10.0.2-internal" xmlns:fx="http://javafx.com/fxml/1" fx:controller="com.sparrowwallet.sparrow.wallet.SendController">
     <center>
-        <VBox spacing="10">
+        <VBox>
             <GridPane styleClass="send-form" hgap="10.0" vgap="10.0">
                 <padding>
                     <Insets left="25.0" right="25.0" top="25.0" />
@@ -48,12 +50,43 @@
                         <TabPane fx:id="paymentTabs" side="RIGHT" styleClass="initial" />
                     </center>
                 </BorderPane>
-                <Form GridPane.columnIndex="0" GridPane.rowIndex="1">
-                    <Fieldset inputGrow="SOMETIMES" text="Fee">
+                <Form styleClass="title-form" GridPane.columnIndex="0" GridPane.rowIndex="1">
+                    <Fieldset inputGrow="ALWAYS" text="Fee"/>
+                </Form>
+                <HBox GridPane.columnIndex="1" GridPane.rowIndex="1" GridPane.columnSpan="2" GridPane.halignment="RIGHT" alignment="CENTER_RIGHT">
+                    <padding>
+                        <Insets right="10.0" />
+                    </padding>
+                    <SegmentedButton>
+                        <toggleGroup>
+                            <ToggleGroup fx:id="feeSelectionToggleGroup" />
+                        </toggleGroup>
+                        <buttons>
+                            <ToggleButton fx:id="targetBlocksToggle" text="Target Blocks" toggleGroup="$feeSelectionToggleGroup">
+                                <tooltip>
+                                    <Tooltip text="Determine fee via estimated number of blocks"/>
+                                </tooltip>
+                                <userData>
+                                    <FeeRateSelection fx:constant="BLOCK_TARGET"/>
+                                </userData>
+                            </ToggleButton>
+                            <ToggleButton fx:id="mempoolSizeToggle" text="Mempool Size" toggleGroup="$feeSelectionToggleGroup">
+                                <tooltip>
+                                    <Tooltip text="Determine fee via current mempool size"/>
+                                </tooltip>
+                                <userData>
+                                    <FeeRateSelection fx:constant="MEMPOOL_SIZE"/>
+                                </userData>
+                            </ToggleButton>
+                        </buttons>
+                    </SegmentedButton>
+                </HBox>
+                <Form GridPane.columnIndex="0" GridPane.rowIndex="2">
+                    <Fieldset inputGrow="SOMETIMES">
                         <Field fx:id="targetBlocksField" text="Block target">
                             <Slider fx:id="targetBlocks" snapToTicks="true" showTickLabels="true" showTickMarks="true" />
                         </Field>
-                        <Field fx:id="feeRangeField" text="Range:">
+                        <Field fx:id="feeRangeField" text="Rate Range:">
                             <Slider fx:id="feeRange" snapToTicks="false" showTickLabels="true" showTickMarks="true" />
                         </Field>
                         <Field fx:id="feeRateField" text="Rate:">
@@ -74,7 +107,7 @@
                         </Field>
                     </Fieldset>
                 </Form>
-                <AnchorPane GridPane.columnIndex="1" GridPane.rowIndex="1" GridPane.columnSpan="2">
+                <AnchorPane GridPane.columnIndex="1" GridPane.rowIndex="2" GridPane.columnSpan="2">
                     <BlockTargetFeeRatesChart fx:id="blockTargetFeeRatesChart" styleClass="feeRatesChart" legendVisible="false" AnchorPane.topAnchor="10" AnchorPane.leftAnchor="20" animated="false">
                         <xAxis>
                             <CategoryAxis side="BOTTOM" />