[gnome-boxes] display-toolbar: Add file transfers button

[Felipe Borges <felipeborges src gnome org>]

commit 4eb94c0ecb876cb4d7513f32757f4bd711a4ba80
Author: Visarion Alexandru <viorel visarion gmail com>
Date:   Sun Dec 17 19:54:08 2017 +0100

    display-toolbar: Add file transfers button
    
    Add a button which lets the users view/manage ongoing
    file transfers between the host and the guest machine
    corresponding to the current display.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=762321

 data/ui/display-toolbar.ui | 20 ++++++++++++++++++++
 src/display-toolbar.vala   | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)
---
diff --git a/data/ui/display-toolbar.ui b/data/ui/display-toolbar.ui
index 65a2721b..8f50947c 100644
--- a/data/ui/display-toolbar.ui
+++ b/data/ui/display-toolbar.ui
@@ -127,6 +127,26 @@
             <property name="pack-type">end</property>
           </packing>
         </child>
+        <child>
+          <object class="GtkButton" id="transfers_button">
+            <property name="visible">False</property>
+            <property name="valign">center</property>
+            <property name="use-underline">True</property>
+            <style>
+              <class name="image-button"/>
+            </style>
+
+            <child>
+              <object class="GtkDrawingArea" id="transfers_drawing_area">
+                <property name="visible">True</property>
+              </object>
+            </child>
+          </object>
+          <packing>
+            <property name="pack-type">end</property>
+          </packing>
+        </child>
+
       </object>
 
       <packing>
diff --git a/src/display-toolbar.vala b/src/display-toolbar.vala
index 9f02126d..34597814 100644
--- a/src/display-toolbar.vala
+++ b/src/display-toolbar.vala
@@ -9,6 +9,11 @@
     [GtkChild]
     private Gtk.Image fullscreen_image;
     [GtkChild]
+    private Gtk.DrawingArea transfers_drawing_area;
+    [GtkChild]
+    public Gtk.Button transfers_button;
+    [GtkChild]
+
     private Gtk.Button back;
     [GtkChild]
     private Gtk.Button fullscreen;
@@ -19,6 +24,21 @@
 
     private AppWindow window;
 
+    private double _progress = 0;
+    public double progress {
+        get {
+            return _progress;
+        }
+        set {
+            if (!transfers_button.get_visible ())
+                transfers_button.set_visible (true);
+
+            _progress =  value;
+
+            transfers_drawing_area.queue_draw ();
+        }
+    }
+
     public DisplayToolbar (bool overlay, bool handle_drag) {
         Object (overlay: overlay,
                 handle_drag: handle_drag);
@@ -68,6 +88,33 @@ public void setup_ui (AppWindow window) {
                 (menu_button.popover as ActionsPopover).update_for_item (window.current_item);
         });
         keys_menu_button.popover = new KeysInputPopover (window);
+        transfers_drawing_area.draw.connect (on_draw);
+    }
+
+    private bool on_draw (Widget da, Cairo.Context ctx) {
+
+        var width = transfers_drawing_area.get_allocated_width ();
+        var height = transfers_drawing_area.get_allocated_height ();
+
+        ctx.set_line_join (Cairo.LineJoin.ROUND);
+
+        var style_context = transfers_button.get_style_context ();
+        var foreground = style_context.get_color (transfers_button.get_state_flags ());
+        var background = foreground;
+
+        background.alpha *= 0.3;
+        ctx.set_source_rgba (background.red, background.green, background.blue, background.alpha);
+        ctx.arc (width / 2, height / 2, height / 3, -Math.PI / 2, 3*Math.PI/2);
+        ctx.fill ();
+
+        ctx.move_to (width / 2, height / 2);
+        ctx.set_source_rgba (foreground.red, foreground.green, foreground.blue, foreground.alpha);
+
+        double radians = -Math.PI/2 + 2*Math.PI * _progress;
+        ctx.arc (width / 2, height / 2, height / 3, -Math.PI / 2, radians);
+        ctx.fill ();
+
+        return true;
     }
 
     private bool button_down;