[simple-scan/gnome-3-38] Add redetect button next to device list

[Bartosz <bkosiorek src gnome org>]

commit 07138a0cc12f4e3ce753b5185d21c8497db8bad6
Author: Iskren Chernev <me iskren info>
Date:   Sun Oct 25 16:31:45 2020 +0000

    Add redetect button next to device list
    
    Refreshing the devices every time a scan is done is time consuming and
    might lead to subtle bugs with faulty backends. Also it is not very
    common to change scanner right after a successful scan.
    
    Replace auto-redetect on new document with a refresh button next to the
    device list.
    
    
    (cherry picked from commit 73e41d59730bb8a98e3e2431b9529e6596d19c87)

 src/app-window.ui   | 41 ++++++++++++++++++++++++++++++++++++++---
 src/app-window.vala | 21 ++++++++++++++-------
 2 files changed, 52 insertions(+), 10 deletions(-)
---
diff --git a/src/app-window.ui b/src/app-window.ui
index 6f42a516..0f7ba27d 100644
--- a/src/app-window.ui
+++ b/src/app-window.ui
@@ -794,10 +794,45 @@
                       </packing>
                     </child>
                     <child>
-                      <object class="GtkComboBox" id="device_combo">
+                      <object class="GtkBox" id="device_combo_box">
                         <property name="visible">False</property>
-                        <property name="model">device_model</property>
-                        <signal name="changed" handler="device_combo_changed_cb" swapped="no"/>
+                        <property name="can_focus">False</property>
+                        <property name="orientation">horizontal</property>
+                        <property name="spacing">10</property>
+                        <child>
+                          <object class="GtkComboBox" id="device_combo">
+                            <property name="visible">True</property>
+                            <property name="model">device_model</property>
+                            <signal name="changed" handler="device_combo_changed_cb" swapped="no"/>
+                          </object>
+                          <packing>
+                            <property name="fill">False</property>
+                          </packing>
+                        </child>
+                        <child>
+                          <object class="GtkButton" id="refresh_devices">
+                            <property name="height_request">40</property>
+                            <property name="visible">True</property>
+                            <property name="can_focus">True</property>
+                            <property name="receives_default">True</property>
+                            <property name="tooltip_text" translatable="yes" comments="Tooltip for stop 
button">Refresh device list</property>
+                            <signal name="clicked" handler="redetect_button_clicked_cb" swapped="no"/>
+                            <child>
+                              <object class="GtkImage">
+                                <property name="visible">True</property>
+                                <property name="can_focus">False</property>
+                                <property name="icon_name">view-refresh-symbolic</property>
+                                <property name="icon_size">1</property>
+                              </object>
+                            </child>
+                            <style>
+                              <class name="image-button"/>
+                            </style>
+                          </object>
+                          <packing>
+                            <property name="fill">False</property>
+                          </packing>
+                        </child>
                       </object>
                     </child>
                   </object>
diff --git a/src/app-window.vala b/src/app-window.vala
index 67f10a8b..6d025b5b 100644
--- a/src/app-window.vala
+++ b/src/app-window.vala
@@ -58,6 +58,8 @@ public class AppWindow : Gtk.ApplicationWindow
     [GtkChild]
     private Gtk.ListStore device_model;
     [GtkChild]
+    private Gtk.Box device_combo_box;
+    [GtkChild]
     private Gtk.ComboBox device_combo;
     [GtkChild]
     private Gtk.Label status_secondary_label;
@@ -252,7 +254,7 @@ public class AppWindow : Gtk.ApplicationWindow
             status_primary_label.set_text (/* Label shown when searching for scanners */
                                            _("Searching for Scanners…"));
             status_secondary_label.visible = false;
-            device_combo.visible = false;
+            device_combo_box.visible = false;
         }
         else if (get_selected_device () != null)
         {
@@ -261,7 +263,7 @@ public class AppWindow : Gtk.ApplicationWindow
                                            _("Ready to Scan"));
             status_secondary_label.set_text (get_selected_device_label ());
             status_secondary_label.visible = false;
-            device_combo.visible = true;
+            device_combo_box.visible = true;
             device_combo.sensitive = true;
         }
         else if (this.missing_driver != null)
@@ -271,7 +273,7 @@ public class AppWindow : Gtk.ApplicationWindow
             /* Instructions to install driver software */
             status_secondary_label.set_markup (_("You need to <a href=\"install-firmware\">install driver 
software</a> for your scanner."));
             status_secondary_label.visible = true;
-            device_combo.visible = false;
+            device_combo_box.visible = false;
         }
         else
         {
@@ -280,7 +282,7 @@ public class AppWindow : Gtk.ApplicationWindow
             /* Hint to user on why there are no scanners detected */
             status_secondary_label.set_text (_("Please check your scanner is connected and powered on"));
             status_secondary_label.visible = true;
-            device_combo.visible = false;
+            device_combo_box.visible = false;
         }
     }
 
@@ -796,9 +798,6 @@ public class AppWindow : Gtk.ApplicationWindow
             if (scanning)
                 stop_scan ();
 
-            have_devices = false;
-            /* Refresh list of devices to detect network scanners, and fix issues with disconnected scanners 
*/
-            redetect ();
             clear_document ();
         });
     }
@@ -820,6 +819,14 @@ public class AppWindow : Gtk.ApplicationWindow
         new_document ();
     }
 
+    [GtkCallback]
+    private void redetect_button_clicked_cb (Gtk.Button button)
+    {
+        have_devices = false;
+        update_scan_status ();
+        redetect ();
+    }
+
     private void scan (ScanOptions options)
     {
         status_primary_label.set_text (/* Label shown when scan started */