From 3e5232d9bd88e95f06db958bdcac4eaf738a8223 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 20 Nov 2013 19:04:55 +0200
Subject: [PATCH] Refactor list item positioning code

This fixes a bug where scrolling didn't quite work properly until each
item had been visible at least once.
---
 source/list.cpp | 98 +++++++++++++++++++------------------------------
 source/list.h   |  7 +---
 2 files changed, 40 insertions(+), 65 deletions(-)

diff --git a/source/list.cpp b/source/list.cpp
index 042eb20..87b27a4 100644
--- a/source/list.cpp
+++ b/source/list.cpp
@@ -110,9 +110,8 @@ void List::set_data(ListData &d)
 
 void List::items_changed()
 {
-	check_view_range();
 	signal_autosize_changed.emit();
-	reposition_items();
+	rebuild();
 }
 
 List::Item *List::create_item(unsigned index)
@@ -122,8 +121,8 @@ List::Item *List::create_item(unsigned index)
 		item = item_factory->create_item(index);
 	else
 		item = new BasicItem(data->get_string(index));
+	item->signal_autosize_changed.connect(sigc::bind(sigc::mem_fun(this, &List::item_autosize_changed), item));
 	add(*item);
-	item->signal_autosize_changed.connect(sigc::mem_fun(this, &List::item_autosize_changed));
 	return item;
 }
 
@@ -162,6 +161,38 @@ void List::rebuild_special(const Part &part)
 {
 	if(part.get_name()=="slider")
 		reposition_child(slider, part);
+	else if(part.get_name()=="items")
+	{
+		const Sides &margin = part.get_margin();
+		unsigned w = geom.w-min(geom.w, margin.left+margin.right);
+		unsigned y = geom.h-min(geom.h, margin.top);
+		for(unsigned i=0; i<items.size(); ++i)
+		{
+			if(i<first || !y)
+				items[i]->set_visible(false);
+			else
+			{
+				Geometry igeom = items[i]->get_geometry();
+				if(igeom.h+margin.bottom<=y)
+				{
+					items[i]->set_visible(true);
+					y -= igeom.h;
+					igeom.x = margin.left;
+					igeom.y = y;
+					igeom.w = w;
+					items[i]->set_geometry(igeom);
+				}
+				else
+				{
+					items[i]->set_visible(false);
+					y = 0;
+				}
+			}
+		}
+
+		check_view_range();
+	}
+
 	Widget::rebuild_special(part);
 }
 
@@ -190,64 +221,11 @@ void List::button_press(int x, int y, unsigned btn)
 	}
 }
 
-void List::on_geometry_change()
-{
-	reposition_items();
-
-	check_view_range();
-}
-
-void List::on_style_change()
-{
-	if(!style)
-		return;
-
-	reposition_items();
-
-	check_view_range();
-}
-
-void List::item_autosize_changed()
+void List::item_autosize_changed(Item *item)
 {
+	item->autosize();
 	signal_autosize_changed.emit();
-	reposition_items();
-}
-
-void List::reposition_items()
-{
-	if(!style)
-		return;
-
-	if(const Part *items_part = style->get_part("items"))
-	{
-		const Sides &margin = items_part->get_margin();
-		unsigned w = geom.w-min(geom.w, margin.left+margin.right);
-		unsigned y = geom.h-min(geom.h, margin.top);
-		for(unsigned i=0; i<items.size(); ++i)
-		{
-			if(i<first || !y)
-				items[i]->set_visible(false);
-			else
-			{
-				Geometry igeom;
-				items[i]->autosize(igeom);
-				if(igeom.h+margin.bottom<=y)
-				{
-					items[i]->set_visible(true);
-					y -= igeom.h;
-					igeom.x = margin.left;
-					igeom.y = y;
-					igeom.w = w;
-					items[i]->set_geometry(igeom);
-				}
-				else
-				{
-					items[i]->set_visible(false);
-					y = 0;
-				}
-			}
-		}
-	}
+	rebuild();
 }
 
 void List::check_view_range()
@@ -285,7 +263,7 @@ void List::slider_value_changed(double value)
 	if(max_scroll>0)
 	{
 		first = max_scroll-static_cast<unsigned>(value);
-		reposition_items();
+		rebuild();
 	}
 }
 
diff --git a/source/list.h b/source/list.h
index 9805176..5b43661 100644
--- a/source/list.h
+++ b/source/list.h
@@ -188,12 +188,9 @@ private:
 
 public:
 	virtual void button_press(int, int, unsigned);
-private:
-	virtual void on_geometry_change();
-	virtual void on_style_change();
 
-	void item_autosize_changed();
-	void reposition_items();
+private:
+	void item_autosize_changed(Item *);
 	void check_view_range();
 	void slider_value_changed(double);
 };
-- 
2.43.0