[rhythmbox] header: allow window dragging for clicks in empty space

[Jonathan Matthew <jmatthew src gnome org>]

commit 8c3cc18280bb495bd82cc21bb02936aef840c202
Author: Jonathan Matthew <jonathan d14n org>
Date:   Thu Mar 13 22:55:47 2014 +1000

    header: allow window dragging for clicks in empty space
    
    When clicking on the area allocated to song information text,
    but not over or near the text, start window drags the same way
    GtkToolbar does, taking the window-dragging style property into
    account.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=678938

 widgets/rb-header.c |   69 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 69 insertions(+), 0 deletions(-)
---
diff --git a/widgets/rb-header.c b/widgets/rb-header.c
index ff22777..15d6d07 100644
--- a/widgets/rb-header.c
+++ b/widgets/rb-header.c
@@ -47,6 +47,8 @@
 #include "rb-file-helpers.h"
 #include "rb-ext-db.h"
 
+#define LABEL_SELECT_PADDING   20
+
 /**
  * SECTION:rb-header
  * @short_description: playback area widgetry
@@ -97,6 +99,7 @@ static void rb_header_sync_time (RBHeader *header);
 static void uri_dropped_cb (RBFadingImage *image, const char *uri, RBHeader *header);
 static void pixbuf_dropped_cb (RBFadingImage *image, GdkPixbuf *pixbuf, RBHeader *header);
 static void image_button_press_cb (GtkWidget *widget, GdkEvent *event, RBHeader *header);
+static gboolean label_button_press_cb (GtkWidget *widget, GdkEventButton *event, RBHeader *header);
 static void art_added_cb (RBExtDB *db, RBExtDBKey *key, const char *filename, GValue *data, RBHeader 
*header);
 static void volume_widget_changed_cb (GtkScaleButton *widget, gdouble volume, RBHeader *header);
 static void player_volume_changed_cb (RBShellPlayer *player, GParamSpec *pspec, RBHeader *header);
@@ -337,6 +340,10 @@ rb_header_constructed (GObject *object)
        gtk_label_set_ellipsize (GTK_LABEL (header->priv->song), PANGO_ELLIPSIZE_END);
        gtk_misc_set_alignment (GTK_MISC (header->priv->song), 0.0, 0.5);
        gtk_grid_attach (GTK_GRID (header->priv->songbox), header->priv->song, 0, 0, 1, 1);
+       g_signal_connect_object (header->priv->song,
+                                "button-press-event",
+                                G_CALLBACK (label_button_press_cb),
+                                header, 0);
 
        header->priv->details = gtk_label_new ("");
        gtk_label_set_use_markup (GTK_LABEL (header->priv->details), TRUE);
@@ -345,6 +352,10 @@ rb_header_constructed (GObject *object)
        gtk_widget_set_hexpand (header->priv->details, TRUE);
        gtk_misc_set_alignment (GTK_MISC (header->priv->details), 0.0, 0.5);
        gtk_grid_attach (GTK_GRID (header->priv->songbox), header->priv->details, 0, 1, 1, 2);
+       g_signal_connect_object (header->priv->details,
+                                "button-press-event",
+                                G_CALLBACK (label_button_press_cb),
+                                header, 0);
 
        /* elapsed time / duration display */
        header->priv->timelabel = gtk_label_new ("");
@@ -1308,3 +1319,61 @@ player_volume_changed_cb (RBShellPlayer *player, GParamSpec *pspec, RBHeader *he
        gtk_scale_button_set_value (GTK_SCALE_BUTTON (header->priv->volume_button), volume);
        header->priv->syncing_volume = FALSE;
 }
+
+static gboolean
+do_window_drag (RBHeader *header)
+{
+       GtkWidget *widget;
+       gboolean window_dragging;
+
+       widget = GTK_WIDGET (header);
+       while (widget != NULL) {
+               if (GTK_IS_TOOLBAR (widget)) {
+                       gtk_widget_style_get (widget, "window-dragging", &window_dragging, NULL);
+                       return window_dragging;
+               }
+
+               widget = gtk_widget_get_parent (widget);
+       }
+
+       return FALSE;
+}
+
+static gboolean
+label_button_press_cb (GtkWidget *label, GdkEventButton *event, RBHeader *header)
+{
+       GtkWidget *window;
+       int min, nat;
+
+       if (do_window_drag (header) == FALSE) {
+               return FALSE;
+       }
+
+       if (gdk_event_triggers_context_menu ((GdkEvent *)event)) {
+               return FALSE;
+       }
+
+       if (event->type != GDK_BUTTON_PRESS) {
+               return FALSE;
+       }
+
+       /* if we're over or near the text, allow the normal selection thing to happen,
+        * otherwise act like a bit of toolbar
+        */
+       gtk_widget_get_preferred_width (label, &min, &nat);
+       if (gtk_widget_get_direction (label) == GTK_TEXT_DIR_RTL) {
+               if (event->x > (gtk_widget_get_allocated_width (label) - (nat + LABEL_SELECT_PADDING))) {
+                       return FALSE;
+               }
+       } else if (event->x < (nat + LABEL_SELECT_PADDING)) {
+               return FALSE;
+       }
+
+       window = gtk_widget_get_toplevel (label);
+       gtk_window_begin_move_drag (GTK_WINDOW (window),
+                                   event->button,
+                                   event->x_root,
+                                   event->y_root,
+                                   event->time);
+       return TRUE;
+}