Voltage spinbutton instead of combobox

Now that the firmware is able to make requests from programmable power
supplies, it's important that the GUI allows setting arbitrary voltages.
This commit makes it do that.

data/pd-buddy-gtk.ui

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!-- Generated with glade 3.20.0 -->
+<!-- Generated with glade 3.20.2 -->
 <interface>
   <requires lib="gtk+" version="3.20"/>
   <object class="GtkImage" id="back-image">
@@ -12,6 +12,11 @@
     <property name="step_increment">1</property>
     <property name="page_increment">10</property>
   </object>
+  <object class="GtkAdjustment" id="voltage-adjustment">
+    <property name="upper">20</property>
+    <property name="step_increment">0.01</property>
+    <property name="page_increment">1</property>
+  </object>
   <object class="GtkApplicationWindow" id="pdb-window">
     <property name="can_focus">False</property>
     <property name="show_menubar">False</property>
@@ -188,7 +193,6 @@
                                                 <property name="label" translatable="yes">_Voltage</property>
                                                 <property name="use_underline">True</property>
                                                 <property name="justify">right</property>
-                                                <property name="mnemonic_widget">voltage-combobox</property>
                                               </object>
                                               <packing>
                                                 <property name="left_attach">0</property>
@@ -196,32 +200,31 @@
                                               </packing>
                                             </child>
                                             <child>
-                                              <object class="GtkComboBoxText" id="voltage-combobox">
+                                              <object class="GtkLabel">
                                                 <property name="visible">True</property>
                                                 <property name="can_focus">False</property>
-                                                <items>
-                                                  <item id="voltage-five" translatable="yes">5</item>
-                                                  <item id="voltage-nine" translatable="yes">9</item>
-                                                  <item id="voltage-twelve" translatable="yes">12</item>
-                                                  <item id="voltage-fifteen" translatable="yes">15</item>
-                                                  <item id="voltage-twenty" translatable="yes">20</item>
-                                                </items>
-                                                <signal name="changed" handler="on_voltage_combobox_changed" swapped="no"/>
+                                                <property name="halign">start</property>
+                                                <property name="label" translatable="yes">V</property>
                                               </object>
                                               <packing>
-                                                <property name="left_attach">1</property>
+                                                <property name="left_attach">2</property>
                                                 <property name="top_attach">0</property>
                                               </packing>
                                             </child>
                                             <child>
-                                              <object class="GtkLabel">
+                                              <object class="GtkSpinButton" id="voltage-spinbutton">
                                                 <property name="visible">True</property>
-                                                <property name="can_focus">False</property>
-                                                <property name="halign">start</property>
-                                                <property name="label" translatable="yes">V</property>
+                                                <property name="can_focus">True</property>
+                                                <property name="width_chars">5</property>
+                                                <property name="text" translatable="yes">0.00</property>
+                                                <property name="input_purpose">number</property>
+                                                <property name="adjustment">voltage-adjustment</property>
+                                                <property name="digits">2</property>
+                                                <property name="numeric">True</property>
+                                                <signal name="value-changed" handler="on_voltage_spinbutton_changed" swapped="no"/>
                                               </object>
                                               <packing>
-                                                <property name="left_attach">2</property>
+                                                <property name="left_attach">1</property>
                                                 <property name="top_attach">0</property>
                                               </packing>
                                             </child>
@@ -266,6 +269,7 @@
                                                 <property name="visible">True</property>
                                                 <property name="can_focus">True</property>
                                                 <property name="margin_left">12</property>
+                                                <property name="width_chars">5</property>
                                                 <property name="input_purpose">number</property>
                                                 <property name="adjustment">current-adjustment</property>
                                                 <property name="digits">2</property>

pd-buddy-gtk.py

@@ -278,7 +278,7 @@ class Handler:
 
     def on_select_list_row_activated(self, selectlist, serport):
         # Get relevant widgets
-        voltage = self.builder.get_object("voltage-combobox")
+        voltage = self.builder.get_object("voltage-spinbutton")
         current = self.builder.get_object("current-spinbutton")
         giveback = self.builder.get_object("giveback-toggle")
         pd_frame = self.builder.get_object("power-delivery-frame")
@@ -314,16 +314,7 @@ class Handler:
         giveback.set_active(bool(self.cfg.flags & pdbuddy.SinkFlags.GIVEBACK))
 
         # Get voltage and current from device and load them into the GUI
-        if self.cfg.v == 5000:
-            voltage.set_active_id('voltage-five')
-        elif self.cfg.v == 9000:
-            voltage.set_active_id('voltage-nine')
-        elif self.cfg.v == 12000:
-            voltage.set_active_id('voltage-twelve')
-        elif self.cfg.v == 15000:
-            voltage.set_active_id('voltage-fifteen')
-        if self.cfg.v == 20000:
-            voltage.set_active_id('voltage-twenty')
+        voltage.set_value(self.cfg.v/1000)
 
         current.set_value(self.cfg.i/1000)
 
@@ -422,8 +413,8 @@ class Handler:
         # Set visibility
         rev.set_reveal_child(self.cfg != self.cfg_clean)
 
-    def on_voltage_combobox_changed(self, combo):
-        self.cfg = self.cfg._replace(v=int(combo.get_active_text()) * 1000)
+    def on_voltage_spinbutton_changed(self, spin):
+        self.cfg = self.cfg._replace(v=int(spin.get_value() * 1000))
 
         self._set_save_button_visibility()