Move back during presentation

Author: Philip-Scott

src/Services/SlideManager.vala

@@ -108,6 +108,14 @@ public class Spice.SlideManager : Object {
         }
     }
 
+    public void previous_slide () {
+        var previous_slide = get_previous_slide (current_slide);
+
+        if (previous_slide != null) {
+            current_slide = previous_slide;
+        }
+    }
+
     public void next_slide () {
         var next_slide = get_next_slide (current_slide);
 
@@ -147,13 +155,15 @@ public class Spice.SlideManager : Object {
 
         do {
             var previous_index = slides.index_of (current) - n++;
-            if (previous_index < slides.size) {
+            if (previous_index >= 0 && previous_index < slides.size) {
                 var slide = slides.get (previous_index);
                 if (slide.visible) {
                     previous_slide = slide;
                     found = true;
                 }
-            } else {
+            }
+
+            if (previous_index < 0) {
                 found = true;
             }
         } while (!found);
@@ -174,6 +184,10 @@ public class Spice.SlideManager : Object {
             next_slide ();
         });
 
+        slide.canvas.previous_slide.connect (() => {
+            previous_slide ();
+        });
+
         slides.add (slide);
         slideshow.add (slide.canvas);
         slideshow.show_all ();

src/Widgets/Canvas.vala

@@ -23,6 +23,7 @@ public class Spice.Canvas : Gtk.Overlay {
     public signal void item_clicked (CanvasItem? item);
     public signal void ratio_changed (double ratio);
     public signal void next_slide ();
+    public signal void previous_slide ();
 
     public signal void configuration_changed ();
     public double current_ratio = 1.0f;
@@ -216,10 +217,15 @@ public class Spice.Canvas : Gtk.Overlay {
     }
 
     public override bool button_press_event (Gdk.EventButton event) {
+        stderr.printf ("Button %u\n", event.button);
         if (!editable) return false;
 
         if (window.is_fullscreen) {
-            next_slide ();
+            if (event.button == 1) {
+                next_slide ();
+            } else if (event.button == 3) {
+                previous_slide ();
+            }
         } else {
             unselect_all ();
             item_clicked (null);
@@ -299,16 +305,7 @@ public class Spice.Canvas : Gtk.Overlay {
         }
 
         public override bool button_press_event (Gdk.EventButton event) {
-            if (!canvas.editable) return false;
-
-            if (window.is_fullscreen) {
-                canvas.next_slide ();
-            } else {
-                canvas.item_clicked (null);
-                canvas.unselect_all ();
-            }
-
-            return true;
+            return canvas.button_press_event (event);
         }
 
         public new void style (string pattern) {