UI|Client: Virtualized items for package lists

There is typically a large number of packages available, so
virtualizing the list contents makes things much faster.

The package item heights are no longer animated so they'll work more
nicely with virtualization.

doomsday/apps/client/include/ui/widgets/homeitemwidget.h

@@ -35,7 +35,15 @@ class HomeItemWidget : public de::GuiWidget, public de::IAssetGroup
     Q_OBJECT
 
 public:
-    HomeItemWidget(de::String const &name = "");
+    enum Flag
+    {
+        NonAnimatedHeight = 0,
+        AnimatedHeight    = 0x1,
+    };
+    Q_DECLARE_FLAGS(Flags, Flag)
+
+public:
+    HomeItemWidget(Flags flags = AnimatedHeight, de::String const &name = "");
 
     de::AssetGroup &assets() override;
 
@@ -97,6 +105,7 @@ class HomeItemWidget : public de::GuiWidget, public de::IAssetGroup
     DENG2_PRIVATE(d)
 };
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(HomeItemWidget::Flags)
 Q_DECLARE_OPERATORS_FOR_FLAGS(HomeItemWidget::LogoFlags)
 
 #endif // DENG_CLIENT_UI_HOME_HOMEITEMWIDGET_H

doomsday/apps/client/include/ui/widgets/packageswidget.h

@@ -76,6 +76,9 @@ class PackagesWidget : public de::GuiWidget, public de::IPersistent
 
     de::LineEditWidget &searchTermsEditor();
 
+    // Events.
+    void initialize();
+
     // Implements IPersistent.
     void operator >> (de::PersistentState &toState) const;
     void operator << (de::PersistentState const &fromState);

doomsday/apps/client/src/ui/home/gamepanelbuttonwidget.cpp

@@ -152,14 +152,14 @@ DENG_GUI_PIMPL(GamePanelButtonWidget)
 
 //- ChildWidgetOrganizer::IFilter ---------------------------------------------
 
-    bool isItemAccepted(ChildWidgetOrganizer const &,
-                        ui::Data const &data, ui::Data::Pos pos) const
+    bool isItemAccepted(ChildWidgetOrganizer const &, ui::Data const &,
+                        ui::Item const &it) const
     {
         // User-created profiles currently have no saves associated with them.
         if (gameProfile.isUserCreated()) return false;
 
         // Only saved sessions for this game are to be included.
-        auto const &item = data.at(pos).as<SavedSessionListData::SaveItem>();
+        auto const &item = it.as<SavedSessionListData::SaveItem>();
         return item.gameId() == gameProfile.game();
     }
 };

doomsday/apps/client/src/ui/home/panelbuttonwidget.cpp

@@ -32,7 +32,7 @@ DENG_GUI_PIMPL(PanelButtonWidget)
 };
 
 PanelButtonWidget::PanelButtonWidget(String const &name)
-    : HomeItemWidget(name)
+    : HomeItemWidget(AnimatedHeight, name)
     , d(new Instance(this))
 {
     setBehavior(Focusable);

doomsday/apps/client/src/ui/widgets/homeitemwidget.cpp

@@ -185,7 +185,7 @@ DENG_GUI_PIMPL(HomeItemWidget)
     }
 };
 
-HomeItemWidget::HomeItemWidget(String const &name)
+HomeItemWidget::HomeItemWidget(Flags flags, String const &name)
     : GuiWidget(name)
     , d(new Instance(this))
 {
@@ -196,16 +196,24 @@ HomeItemWidget::HomeItemWidget(String const &name)
                            style().fonts().font("default").height() +
                            style().fonts().font("default").lineSpacing();
 
-    AutoRef<Rule> smoothHeight(new AnimationRule(d->label->rule().height(), 0.3));
+    AutoRef<Rule> height;
+    if(flags.testFlag(AnimatedHeight))
+    {
+        height.reset(new AnimationRule(d->label->rule().height(), 0.3));
+    }
+    else
+    {
+        height.reset(d->label->rule().height());
+    }
 
     d->background->rule()
             .setInput(Rule::Top,    rule().top())
-            .setInput(Rule::Height, smoothHeight)
+            .setInput(Rule::Height, height)
             .setInput(Rule::Left,   d->icon->rule().right())
             .setInput(Rule::Right,  rule().right());
 
     d->icon->rule()
-            .setSize(iconSize,    smoothHeight)
+            .setSize(iconSize,    height)
             .setInput(Rule::Left, rule().left())
             .setInput(Rule::Top,  rule().top());
     d->icon->set(Background(Background::BorderGlow,
@@ -218,7 +226,7 @@ HomeItemWidget::HomeItemWidget(String const &name)
     d->label->margins().setRight(*d->labelRightMargin + rule("gap"));
 
     // Use an animated height rule for smoother list layout behavior.
-    rule().setInput(Rule::Height, smoothHeight);
+    rule().setInput(Rule::Height, height);
 }
 
 AssetGroup &HomeItemWidget::assets()

doomsday/apps/client/src/ui/widgets/packageswidget.cpp

@@ -27,6 +27,7 @@
 #include <de/DocumentPopupWidget>
 #include <de/FileSystem>
 #include <de/LineEditWidget>
+#include <de/Loop>
 #include <de/MenuWidget>
 #include <de/PackageLoader>
 #include <de/PopupButtonWidget>
@@ -82,6 +83,7 @@ DENG_GUI_PIMPL(PackagesWidget)
 , public ChildWidgetOrganizer::IFilter
 , public ChildWidgetOrganizer::IWidgetFactory
 {
+    LoopCallback mainCall;
     LineEditWidget *search;
     ButtonWidget *clearSearch;
     HomeMenuWidget *menu;
@@ -135,7 +137,8 @@ DENG_GUI_PIMPL(PackagesWidget)
     {
     public:
         PackageListWidget(PackageItem const &item, PackagesWidget &owner)
-            : _owner(owner)
+            : HomeItemWidget(NonAnimatedHeight) // virtualized, so don't make things difficult
+            , _owner(owner)
             , _item(&item)
         {
             icon().setImageFit(ui::FitToSize | ui::OriginalAspectRatio);
@@ -352,13 +355,21 @@ DENG_GUI_PIMPL(PackagesWidget)
                 .setInput(Rule::Top,   search->rule().bottom());
         menu->organizer().setWidgetFactory(*this);
         menu->organizer().setFilter(*this);
+        menu->setVirtualizationEnabled(true, rule("gap").valuei()*2 + rule("unit").valuei() +
+                                       int(style().fonts().font("default").height().value()*3));
 
         QObject::connect(search, &LineEditWidget::editorContentChanged,
                          [this] () { updateFilterTerms(); });
         QObject::connect(search, &LineEditWidget::enterPressed,
                          [this] () { focusFirstListedPackge(); });
     }
 
+    ~Instance()
+    {
+        // Private instance deleted before child widgets.
+        menu->organizer().unsetFilter();
+    }
+
     void populate()
     {
         StringList packages = App::packageLoader().findAllPackages();
@@ -405,8 +416,13 @@ DENG_GUI_PIMPL(PackagesWidget)
 
     void updateFilterTerms()
     {
-        /// @todo Parse quoted terms. -jk
-        setFilterTerms(search->text().strip().split(QRegExp("\\s"), QString::SkipEmptyParts));
+        // Refiltering will potentially alter the widget tree, so doing it during
+        // event handling is not a great idea.
+        mainCall.enqueue([this] ()
+        {
+            /// @todo Parse quoted terms. -jk
+            setFilterTerms(search->text().strip().split(QRegExp("\\s"), QString::SkipEmptyParts));
+        });
     }
 
     void setFilterTerms(QStringList const &terms)
@@ -438,10 +454,10 @@ DENG_GUI_PIMPL(PackagesWidget)
         return true;
     }
 
-    bool isItemAccepted(ChildWidgetOrganizer const &,
-                        ui::Data const &data, ui::Data::Pos pos) const
+    bool isItemAccepted(ChildWidgetOrganizer const &, ui::Data const &,
+                        ui::Item const &it) const
     {
-        auto &item = data.at(pos).as<PackageItem>();
+        auto &item = it.as<PackageItem>();
 
         // The terms are looked in:
         // - title
@@ -569,6 +585,12 @@ LineEditWidget &PackagesWidget::searchTermsEditor()
     return *d->search;
 }
 
+void PackagesWidget::initialize()
+{
+    GuiWidget::initialize();
+    d->menu->organizer().setVisibleArea(root().viewTop(), root().viewBottom());
+}
+
 void PackagesWidget::operator >> (PersistentState &toState) const
 {
     if (name().isEmpty()) return;