[gnome-music/wip/jfelder/albumwidget-full-scrollarea: 2/4] albumwidget: Simplify margin handling

[Jean Felder <jfelder src gnome org>]

commit 369021fc9f8a2a47b43f0c5fb30e0ecad14da439
Author: Jean Felder <jfelder src gnome org>
Date:   Tue Jan 8 20:49:01 2019 +0100

    albumwidget: Simplify margin handling
    
    Move top an bottom margins to the main box. Update disc box's margin
    at init time to align it with the album info box.

 data/ui/AlbumWidget.ui            | 16 +++++-----------
 gnomemusic/widgets/albumwidget.py | 15 +++++++++------
 2 files changed, 14 insertions(+), 17 deletions(-)
---
diff --git a/data/ui/AlbumWidget.ui b/data/ui/AlbumWidget.ui
index 9909ac74..b53160db 100644
--- a/data/ui/AlbumWidget.ui
+++ b/data/ui/AlbumWidget.ui
@@ -16,18 +16,19 @@
         <property name="vexpand">True</property>
         <property name="hscrollbar_policy">never</property>
         <child>
-          <object class="GtkBox">
+          <object class="GtkBox" id="_main_box">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
+            <property name="margin_start">32</property>
+            <property name="margin_end">32</property>
+            <property name="margin_top">64</property>
+            <property name="margin_bottom">64</property>
             <child>
               <object class="GtkBox" id="_album_info">
                 <property name="visible">True</property>
                 <property name="can_focus">False</property>
                 <property name="halign">end</property>
-                <property name="margin_start">32</property>
                 <property name="margin_end">32</property>
-                <property name="margin_top">64</property>
-                <property name="margin_bottom">32</property>
                 <property name="valign">start</property>
                 <property name="vexpand">True</property>
                 <signal name="size-allocate" handler="_on_album_info_size_changed" swapped="no"/>
@@ -227,15 +228,8 @@
               </packing>
             </child>
             <child>
-              <!-- TODO: The top of the coverart is the same vertical -->
-              <!-- position as the top of the album songs, however -->
-              <!-- since we set a top margins for the discbox -->
-              <!-- subtract that margin here. A cleaner solution is appreciated. -->
               <object class="DiscListBox" id="_disc_listbox">
                 <property name="can_focus">False</property>
-                <property name="margin_top">48</property>
-                <property name="margin_bottom">64</property>
-                <property name="margin_end">32</property>
                 <property name="halign">start</property>
                 <property name="orientation">vertical</property>
                 <property name="selection_mode_allowed">True</property>
diff --git a/gnomemusic/widgets/albumwidget.py b/gnomemusic/widgets/albumwidget.py
index 1a0f66ab..3e6f1ea3 100644
--- a/gnomemusic/widgets/albumwidget.py
+++ b/gnomemusic/widgets/albumwidget.py
@@ -51,6 +51,7 @@ class AlbumWidget(Gtk.EventBox):
     _composer_info_label = Gtk.Template.Child()
     _cover_stack = Gtk.Template.Child()
     _disc_listbox = Gtk.Template.Child()
+    _main_box = Gtk.Template.Child()
     _released_info_label = Gtk.Template.Child()
     _running_info_label = Gtk.Template.Child()
     _scrolled_window = Gtk.Template.Child()
@@ -74,7 +75,6 @@ class AlbumWidget(Gtk.EventBox):
         super().__init__()
 
         self._songs = []
-        self._initial_margin_top = self._album_info.props.margin_top
         self._album_info_height = 0
 
         self._cover_stack.props.size = Art.Size.LARGE
@@ -150,7 +150,7 @@ class AlbumWidget(Gtk.EventBox):
 
         self._set_composer_label(album)
 
-        self._album_info.props.margin_top = self._initial_margin_top
+        self._album_info.props.margin_top = 0
 
         self._player.connect('song-changed', self._update_model)
 
@@ -238,6 +238,10 @@ class AlbumWidget(Gtk.EventBox):
                     disc.props.show_disc_label = False
                 self._disc_listbox.add(disc)
 
+            # update first dic box margin to align it with album_info
+            first_disc_box = self._disc_listbox.get_children()[0]
+            first_disc_box.props.margin_top = self._album_info.props.margin_top
+
             self._set_duration_label()
             self._update_model(self._player)
 
@@ -292,8 +296,7 @@ class AlbumWidget(Gtk.EventBox):
 
     @log
     def _on_scroll_value_changed(self, adjustment):
-        self._album_info.props.margin_top = (adjustment.props.value
-                                             + self._initial_margin_top)
+        self._album_info.props.margin_top = adjustment.props.value
 
     @Gtk.Template.Callback()
     @log
@@ -301,6 +304,6 @@ class AlbumWidget(Gtk.EventBox):
         if allocation.height != self._album_info_height:
             self._album_info_height = allocation.height
             min_height = (allocation.height
-                          + self._initial_margin_top
-                          + self._album_info.props.margin_bottom)
+                          + self._main_box.props.margin_top
+                          + self._main_box.props.margin_bottom)
             self._scrolled_window.props.min_content_height = min_height