[gnome-control-center/wip/carlosg/remapping-screen-tablets] wacom: Allow decoupling screen tablets from their respective output

[Carlos Garnacho <carlosg src gnome org>]

commit fee620263c49369c4288d9998c27aa718d8cef1d
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Dec 20 17:57:10 2018 +0100

    wacom: Allow decoupling screen tablets from their respective output
    
    This is useful for 2 cases:
    - Tablet-input-driven setups where it makes sense to be able to quickly
      reach other monitors with the tablet.
    - (Hopefully a minority) Cases where our display mapping heuristics go
      wrong and tablet gets assigned to a wrong monitor.
    
    Closes: https://gitlab.gnome.org/GNOME/gnome-control-center/issues/239

 panels/wacom/cc-wacom-page.c           | 100 ++++++++++++++++++++++++++++++---
 panels/wacom/gnome-wacom-properties.ui |  41 +++++++++++++-
 2 files changed, 131 insertions(+), 10 deletions(-)
---
diff --git a/panels/wacom/cc-wacom-page.c b/panels/wacom/cc-wacom-page.c
index 47fb59579..4113930e1 100644
--- a/panels/wacom/cc-wacom-page.c
+++ b/panels/wacom/cc-wacom-page.c
@@ -595,6 +595,32 @@ set_mode_from_gsettings (GtkComboBox *combo,
        gtk_combo_box_set_active (combo, mapping);
 }
 
+static void
+update_display_decoupled_sensitivity (CcWacomPage *page,
+                                     gboolean     active)
+{
+       if (get_layout_type (page->stylus) != LAYOUT_SCREEN)
+               return;
+
+       gtk_widget_set_sensitive (WID ("label-trackingmode"), active);
+       gtk_widget_set_sensitive (WID ("combo-tabletmode"), active);
+       gtk_widget_set_sensitive (WID ("display-mapping-button-2"), active);
+
+       gtk_widget_set_sensitive (WID ("button-calibrate"), !active);
+}
+
+static void
+set_display_decoupled_from_gsettings (GtkSwitch *sw,
+                                     CcWacomPage *page)
+{
+       GStrv output = g_settings_get_strv (page->wacom_settings, "output");
+       gboolean active = g_strcmp0 (output[0], "") != 0;
+
+       gtk_switch_set_active (sw, active);
+       update_display_decoupled_sensitivity (page, active);
+       g_strfreev (output);
+}
+
 static void
 combobox_text_cellrenderer (GtkComboBox *combo, int name_column)
 {
@@ -622,6 +648,51 @@ mouse_clicked_cb (GtkButton   *button,
        return TRUE;
 }
 
+static void
+decouple_display_toggled_cb (GtkSwitch  *sw,
+                            GParamSpec  *pspec,
+                            CcWacomPage *page)
+{
+       gboolean active = gtk_switch_get_active (sw);
+
+       update_display_decoupled_sensitivity (page, active);
+
+       if (!active) {
+               cc_wacom_device_set_output (page->stylus, NULL);
+       } else {
+               GdkScreen *screen;
+               GnomeRRScreen *rr_screen;
+               GnomeRROutput **outputs, *picked = NULL;
+               GError *error = NULL;
+               int i;
+
+               screen = gtk_widget_get_screen (GTK_WIDGET (sw));
+               rr_screen = gnome_rr_screen_new (screen, &error);
+               if (error) {
+                       g_warning ("Could not connect to display manager: %s", error->message);
+                       g_error_free (error);
+                       return;
+               }
+
+               outputs = gnome_rr_screen_list_outputs (rr_screen);
+
+               /* Pick *some* output here. decoupled mode can only jump across
+                * monitors, not map to the full span of those. We prefer the
+                * builtin display, falling back to the first output found if
+                * there's none.
+                */
+               for (i = 0; outputs[i] != NULL; i++) {
+                       if (gnome_rr_output_is_builtin_display (outputs[i]))
+                               picked = outputs[i];
+               }
+
+               if (!picked)
+                       picked = outputs[0];
+
+               cc_wacom_device_set_output (page->stylus, picked);
+       }
+}
+
 /* Boilerplate code goes below */
 
 static void
@@ -771,6 +842,10 @@ cc_wacom_page_init (CcWacomPage *page)
 
        g_signal_connect (G_OBJECT (WID ("display-mapping-button")), "clicked",
                          G_CALLBACK (display_mapping_button_clicked_cb), page);
+       g_signal_connect (G_OBJECT (WID ("display-mapping-button-2")), "clicked",
+                         G_CALLBACK (display_mapping_button_clicked_cb), page);
+       g_signal_connect (WID ("switch-decouple-display"), "notify::active",
+                         G_CALLBACK (decouple_display_toggled_cb), page);
 
        page->nav = cc_wacom_nav_button_new ();
         gtk_widget_set_halign (page->nav, GTK_ALIGN_END);
@@ -812,6 +887,14 @@ remove_mouse_link (CcWacomPage *page)
         gtk_widget_destroy (WID ("mouse-link"));
 }
 
+static void
+remove_decouple_options (CcWacomPage *page)
+{
+       gtk_widget_destroy (WID ("label-decouple-display"));
+       gtk_widget_destroy (WID ("switch-decouple-display"));
+       gtk_widget_destroy (WID ("display-mapping-button-2"));
+}
+
 static gboolean
 has_monitor (CcWacomPage *page)
 {
@@ -844,27 +927,27 @@ update_tablet_ui (CcWacomPage *page,
        case LAYOUT_NORMAL:
                remove_left_handed (page);
                remove_display_link (page);
+               remove_decouple_options (page);
                break;
        case LAYOUT_REVERSIBLE:
                remove_display_link (page);
+               remove_decouple_options (page);
                break;
        case LAYOUT_SCREEN:
                remove_left_handed (page);
 
-               gtk_widget_destroy (WID ("combo-tabletmode"));
-               gtk_widget_destroy (WID ("label-trackingmode"));
                gtk_widget_destroy (WID ("display-mapping-button"));
 
                gtk_widget_show (WID ("button-calibrate"));
                gtk_widget_set_sensitive (WID ("button-calibrate"),
                                          has_monitor (page));
 
-               gtk_container_child_set (CWID ("main-grid"),
-                                        WID ("tablet-buttons-box"),
-                                        "top_attach", 1, NULL);
-               gtk_container_child_set (CWID ("main-grid"),
-                                        WID ("display-link"),
-                                        "top_attach", 2, NULL);
+               gtk_container_child_set (CWID ("main-controls-grid"),
+                                        WID ("label-trackingmode"),
+                                        "top_attach", 5, NULL);
+               gtk_container_child_set (CWID ("main-controls-grid"),
+                                        WID ("combo-tabletmode"),
+                                        "top_attach", 5, NULL);
                break;
        default:
                g_assert_not_reached ();
@@ -913,6 +996,7 @@ cc_wacom_page_new (CcWacomPanel  *panel,
        /* FIXME move this to construct */
        page->wacom_settings  = cc_wacom_device_get_settings (stylus);
        set_mode_from_gsettings (GTK_COMBO_BOX (WID ("combo-tabletmode")), page);
+       set_display_decoupled_from_gsettings (GTK_SWITCH (WID ("switch-decouple-display")), page);
 
        /* Tablet name */
        gtk_label_set_text (GTK_LABEL (WID ("label-tabletmodel")), cc_wacom_device_get_name (stylus));
diff --git a/panels/wacom/gnome-wacom-properties.ui b/panels/wacom/gnome-wacom-properties.ui
index 292c51978..4ac842410 100644
--- a/panels/wacom/gnome-wacom-properties.ui
+++ b/panels/wacom/gnome-wacom-properties.ui
@@ -368,10 +368,47 @@
                       </packing>
                     </child>
                     <child>
-                      <placeholder/>
+                      <object class="GtkLabel" id="label-decouple-display">
+                        <property name="visible">True</property>
+                        <property name="can_focus">False</property>
+                        <property name="halign">end</property>
+                        <property name="valign">center</property>
+                        <property name="label" translatable="yes">Decouple Display</property>
+                        <style>
+                          <class name="dim-label"/>
+                        </style>
+                      </object>
+                      <packing>
+                        <property name="left_attach">0</property>
+                        <property name="top_attach">4</property>
+                      </packing>
                     </child>
                     <child>
-                      <placeholder/>
+                      <object class="GtkSwitch" id="switch-decouple-display">
+                        <property name="visible">True</property>
+                        <property name="can_focus">True</property>
+                        <property name="halign">start</property>
+                        <property name="valign">center</property>
+                        <property name="active">True</property>
+                      </object>
+                      <packing>
+                        <property name="left_attach">1</property>
+                        <property name="top_attach">4</property>
+                      </packing>
+                    </child>
+                    <child>
+                      <object class="GtkButton" id="display-mapping-button-2">
+                        <property name="label" translatable="yes">Map to Monitor…</property>
+                        <property name="use_action_appearance">False</property>
+                        <property name="visible">True</property>
+                        <property name="can_focus">True</property>
+                        <property name="receives_default">True</property>
+                        <property name="halign">start</property>
+                      </object>
+                      <packing>
+                        <property name="left_attach">1</property>
+                        <property name="top_attach">6</property>
+                      </packing>
                     </child>
                   </object>
                   <packing>