X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Flist.cpp;h=a9cbcc1c5f02af4080ca895f18525dfcea61af1e;hb=HEAD;hp=19559d1d05b8f51606fc2cd36a4bce5689344901;hpb=1aa6cd9b865e366737dcc9d2d36c4f8faed5bc4f;p=libs%2Fgltk.git

diff --git a/source/list.cpp b/source/list.cpp
index 19559d1..a028571 100644
--- a/source/list.cpp
+++ b/source/list.cpp
@@ -1,317 +1,711 @@
+#include <msp/core/raii.h>
+#include <msp/debug/demangle.h>
 #include <msp/gl/matrix.h>
 #include <msp/gl/meshbuilder.h>
+#include <msp/input/keys.h>
+#include <msp/strings/format.h>
 #include "graphic.h"
 #include "list.h"
 #include "part.h"
 #include "style.h"
 #include "text.h"
-#include "vslider.h"
 
 using namespace std;
 
 namespace Msp {
 namespace GLtk {
 
+incompatible_data::incompatible_data(const type_info &ti):
+	logic_error("expected "+Debug::demangle(ti.name()))
+{ }
+
+
+List::List(unique_ptr<ListData> d):
+	List(*d)
+{
+	own_data = move(d);
+}
+
 List::List():
-	sel_index(-1),
-	first(0),
-	n_visible(1),
-	row_height(1),
-	items_part(0)
+	List(make_unique<BasicListData<string>>())
+{ }
+
+List::List(ListData &d):
+	data(&d),
+	observer(make_unique<DataObserver>(*this))
 {
+	input_type = INPUT_NAVIGATION;
+
 	add(slider);
 	slider.set_step(1);
 	slider.signal_value_changed.connect(sigc::mem_fun(this, &List::slider_value_changed));
 }
 
-void List::autosize()
+void List::autosize_special(const Part &part, Geometry &ageom) const
 {
-	autosize_rows(5);
-}
-
-void List::autosize_rows(unsigned n)
-{
-	if(!style)
-		return;
-
-	Widget::autosize();
-
-	if(items_part)
+	if(part.get_name()=="items")
 	{
-		const Sides &margin = items_part->get_margin();
-		const GL::Font &font = style->get_font();
-		float font_size = style->get_font_size();
+		const Sides &margin = part.get_margin();
 
-		unsigned max_w = 0;
-		for(vector<string>::iterator i=items.begin(); i!=items.end(); ++i)
+		unsigned items_w = 0;
+		unsigned items_h = 0;
+		for(size_t i=0; i<items.size(); ++i)
 		{
-			unsigned w = static_cast<unsigned>(font.get_string_width(*i)*font_size);
-			max_w = max(max_w, w);
+			Geometry igeom;
+			items[i]->autosize(igeom);
+			items_w = max(items_w, igeom.w);
+			items_h = max(items_h, igeom.h);
 		}
 
-		geom.w = max(geom.w, max_w+margin.left+margin.right);
-		geom.h = max(geom.h, n*row_height+margin.top+margin.bottom);
-	}
-
-	if(const Part *slider_part = style->get_part("slider"))
-	{
-		Geometry sgeom = slider_part->get_geometry();
-		if(!sgeom.w || !sgeom.h)
+		if(view_mode==GRID)
 		{
-			slider.autosize();
-			if(!sgeom.w)
-				sgeom.w = slider.get_geometry().w;
-			if(!sgeom.h)
-				sgeom.h = slider.get_geometry().h;
+			unsigned r = view_rows;
+			unsigned c = view_columns;
+			if(r==0 && c==0)
+				r = sqrt(items.size());
+			if(r==0)
+				r = (items.size()+c-1)/c;
+			if(c==0)
+				c = (items.size()+r-1)/r;
+			items_w *= c;
+			items_h *= r;
 		}
+		else
+			items_h *= (view_rows==0 ? items.size() : view_rows);
 
-		const Sides &margin = slider_part->get_margin();
-		geom.w = max(geom.w, sgeom.w+margin.left+margin.right);
-		geom.h = max(geom.h, sgeom.h+margin.top+margin.bottom);
-
-		reposition_slider();
+		ageom.w = max(ageom.w, items_w+margin.left+margin.right);
+		ageom.h = max(ageom.h, items_h+margin.top+margin.bottom);
 	}
-
-	check_view_range();
-	rebuild();
+	else if(part.get_name()=="slider")
+		autosize_child(slider, part, ageom);
 }
 
-void List::autosize_all()
+void List::set_data(ListData &d)
 {
-	autosize_rows(items.size());
-}
+	if(item_factory)
+		item_factory->set_data(d);
 
-void List::append(const string &v)
-{
-	items.push_back(v);
-	items_changed();
-}
+	observer.reset();
+	own_data.reset();
 
-void List::insert(unsigned i, const string &v)
-{
-	if(i>items.size())
-		throw out_of_range("List::insert");
+	data = &d;
+	observer = make_unique<DataObserver>(*this);
+
+	items.clear();
+	size_t n_items = data->size();
+	for(size_t i=0; i<n_items; ++i)
+		items.emplace_back(create_item(i));
 
-	items.insert(items.begin()+i, v);
 	items_changed();
 }
 
-void List::remove(unsigned i)
+void List::items_changed()
 {
-	if(i>items.size())
-		throw out_of_range("List::remove");
-
-	items.erase(items.begin()+i);
-	if(sel_index>static_cast<int>(i))
-		--sel_index;
-	else if(sel_index==static_cast<int>(i))
-		sel_index = -1;
+	signal_autosize_changed.emit();
+	mark_rebuild();
+}
 
-	items_changed();
+unique_ptr<List::Item> List::create_item(size_t index)
+{
+	unique_ptr<Item> item;
+	if(item_factory)
+		item = item_factory->create_item(index);
+	else
+		item = make_unique<BasicItem>(data->get_string(index));
+	if(index==sel_index)
+		item->set_active(true);
+	add(*item);
+	item->autosize();
+	item->signal_autosize_changed.connect(sigc::bind(sigc::mem_fun(this, &List::item_autosize_changed), item.get()));
+	return item;
 }
 
-void List::clear()
+void List::set_view_size(unsigned s)
 {
-	items.clear();
-	sel_index = -1;
-	items_changed();
+	set_view_size(s, s);
 }
 
-void List::items_changed()
+void List::set_view_size(unsigned r, unsigned c)
 {
-	check_view_range();
+	view_rows = r;
+	view_columns = c;
 	signal_autosize_changed.emit();
-	rebuild();
 }
 
-void List::set_selected_index(int i)
+void List::set_view_all()
+{
+	set_view_size(0);
+}
+
+void List::set_selected_index(size_t i)
 {
-	if(i<0)
-		sel_index = -1;
-	else if(i<static_cast<int>(items.size()))
+	if(i>=data->size() && i!=INVALID_INDEX)
+		throw out_of_range("List::set_selected_index");
+
+	if(i==sel_index)
+		return;
+
+	if(sel_index!=INVALID_INDEX)
+		items[sel_index]->set_active(false);
+
+	sel_index = i;
+	focus_index = i;
+	if(i==INVALID_INDEX)
 	{
-		sel_index = i;
-		signal_item_selected.emit(sel_index, items[sel_index]);
+		set_input_focus(nullptr);
+		signal_selection_cleared.emit();
 	}
 	else
-		throw out_of_range("List::set_selected_index");
+	{
+		items[sel_index]->set_active(true);
+		if(state&FOCUS)
+			set_input_focus(items[focus_index].get());
+		signal_item_selected.emit(sel_index);
+	}
+}
+
+void List::set_selected_item(Widget *item)
+{
+	for(size_t i=rows[first_row].first; (i<items.size() && items[i]->is_visible()); ++i)
+		if(item==items[i].get())
+			return set_selected_index(i);
 }
 
-const string &List::get_selected() const
+void List::rebuild_special(const Part &part)
 {
-	if(sel_index<0)
-		throw logic_error("sel_index<0");
+	if(part.get_name()=="slider")
+		reposition_child(slider, part);
+	else if(part.get_name()=="items")
+	{
+		SetFlag flag(ignore_slider_change);
+		reposition_items(true);
+		size_t old_first_row = first_row;
+		size_t old_max_scroll = max_scroll;
+		check_view_range();
+		if(first_row!=old_first_row || max_scroll!=old_max_scroll)
+			reposition_items(false);
+	}
 
-	return items[sel_index];
+	Widget::rebuild_special(part);
 }
 
-void List::rebuild_special(const Part &part, CachedPart &cache)
+void List::render_special(const Part &part, GL::Renderer &renderer) const
 {
 	if(part.get_name()=="items")
 	{
-		const Sides &margin = part.get_margin();
-		Geometry pgeom = geom;
-		pgeom.h = row_height+margin.top+margin.bottom;
+		for(size_t i=rows[first_row].first; (i<items.size() && items[i]->is_visible()); ++i)
+			items[i]->render(renderer);
+	}
+	else if(part.get_name()=="slider")
+		slider.render(renderer);
+}
 
-		const GL::Font &font = style->get_font();
-		cache.texture = &font.get_texture();
-		cache.clear_mesh();
+bool List::key_press(unsigned key, unsigned mod)
+{
+	if(key==Input::KEY_UP && mod==MOD_CTRL)
+		move_focus(NAV_UP, false);
+	else if(key==Input::KEY_DOWN && mod==MOD_CTRL)
+		move_focus(NAV_DOWN, false);
+	else
+		return false;
 
-		GL::MeshBuilder bld(*cache.mesh);
-		bld.color(style->get_font_color());
-		bld.matrix() *= GL::Matrix::translation(pgeom.x, pgeom.y+geom.h-pgeom.h, 0);
+	return true;
+}
 
-		for(unsigned i=0; (i<n_visible && first+i<items.size()); ++i)
+void List::button_press(int x, int y, unsigned btn)
+{
+	if(btn==4 || btn==5)
+	{
+		size_t change = 3;
+		if(btn==4)
+		{
+			change = min(first_row, change);
+			slider.set_value(max_scroll-(first_row-change));
+		}
+		else if(btn==5)
 		{
-			if(i!=0)
-				bld.matrix() *= GL::Matrix::translation(0, -static_cast<int>(row_height), 0);
+			change = min(max_scroll-first_row, change);
+			slider.set_value(max_scroll-(first_row+change));
+		}
+	}
+	else
+	{
+		Container::button_press(x, y, btn);
+		if(click_focus && btn==1)
+			set_selected_item(click_focus);
+	}
+}
 
-			GL::MatrixStack::Push _pushm(bld.matrix());
-			bld.matrix() *= GL::Matrix::scaling(style->get_font_size());
+void List::touch_press(int x, int y, unsigned finger)
+{
+	if(finger==0)
+	{
+		dragging = true;
+		drag_start_x = x;
+		drag_start_y = y;
+	}
+}
 
-			style->get_font().build_string(items[first+i], bld);
+void List::touch_release(int x, int y, unsigned finger)
+{
+	if(finger==0)
+	{
+		int dx = x-drag_start_x;
+		int dy = y-drag_start_y;
+		if(dx*dx+dy*dy<25)
+		{
+			Container::touch_press(drag_start_x, drag_start_y, finger);
+			if(touch_focus)
+				set_selected_item(touch_focus);
+			Container::touch_motion(x, y, finger);
+			Container::touch_release(x, y, finger);
 		}
+		dragging = false;
 	}
-	else if(part.get_name()=="selection")
+}
+
+void List::touch_motion(int, int y, unsigned finger)
+{
+	if(finger==0 && !items.empty() && dragging)
 	{
-		if(sel_index>=static_cast<int>(first) && sel_index<static_cast<int>(first+n_visible))
+		int dy = y-drag_start_y;
+		if(dy>0 && first_row<max_scroll)
+		{
+			int row_h = rows[first_row].height;
+			if(dy>row_h)
+			{
+				drag_start_y += row_h;
+				slider.set_value(max_scroll-(first_row+1));
+			}
+		}
+		else if(dy<0 && first_row>0)
 		{
-			const Sides &margin = part.get_margin();
+			int row_h = rows[first_row-1].height;
+			if(-dy>row_h)
+			{
+				drag_start_y -= row_h;
+				slider.set_value(max_scroll-(first_row-1));
+			}
+		}
+	}
+}
 
-			Geometry pgeom = geom;
-			pgeom.h = row_height;
-			pgeom.w -= margin.left+margin.right;
+void List::focus_in()
+{
+	Container::focus_in();
+	if(focus_index!=INVALID_INDEX && items[focus_index]->is_visible())
+		set_input_focus(items[focus_index].get());
+	else
+	{
+		if(sel_index!=INVALID_INDEX && items[sel_index]->is_visible())
+			set_focus_index(sel_index);
+		else if(!items.empty())
+			set_focus_index(rows[first_row].first);
+	}
+}
 
-			Geometry rgeom = part.get_geometry();
-			rgeom.y += geom.h-margin.top-row_height*(sel_index-first+1);
-			rgeom.x += margin.left;
-			part.get_alignment().apply(rgeom, pgeom);
+bool List::navigate(Navigation nav)
+{
+	if((nav==NAV_UP || nav==NAV_DOWN || ((nav==NAV_LEFT || nav==NAV_RIGHT) && view_mode==GRID)) && !items.empty())
+		move_focus(nav, true);
+	else if(nav==NAV_ACTIVATE)
+		set_selected_index(focus_index);
+	else
+		return false;
 
-			cache.texture = part.get_graphic(state)->get_texture();
-			cache.clear_mesh();
+	return true;
+}
 
-			GL::MeshBuilder bld(*cache.mesh);
-			bld.matrix() *= GL::Matrix::translation(rgeom.x, rgeom.y, 0);
-			part.get_graphic(state)->build(rgeom.w, rgeom.h, bld);
-		}
+void List::on_style_change()
+{
+	items_part = (style ? style->find_part("items") : nullptr);
+}
+
+void List::move_focus(Navigation nav, bool select)
+{
+	if(nav==NAV_UP && view_mode==GRID)
+	{
+		size_t row = item_index_to_row(focus_index);
+		if(row>0)
+			set_focus_index(rows[row-1].first+focus_index-rows[row].first);
+		else
+			set_focus_index(0);
+	}
+	else if(nav==NAV_DOWN && view_mode==GRID)
+	{
+		size_t row = item_index_to_row(focus_index);
+		if(row+1<rows.size())
+			set_focus_index(rows[row+1].first+focus_index-rows[row].first);
 		else
-			cache.texture = 0;
+			set_focus_index(items.size()-1);
+	}
+	else if(nav==NAV_UP || (nav==NAV_LEFT && view_mode==GRID))
+	{
+		if(focus_index>0)
+			set_focus_index(focus_index-1);
 	}
+	else if(nav==NAV_DOWN || (nav==NAV_RIGHT && view_mode==GRID))
+	{
+		if(focus_index+1<items.size())
+			set_focus_index(focus_index+1);
+	}
+
+	if(select)
+		set_selected_index(focus_index);
 }
 
-void List::render_special(const Part &part) const
+void List::set_focus_index(size_t i)
 {
-	if(part.get_name()=="slider")
-		slider.render();
+	focus_index = i;
+	if(focus_index!=INVALID_INDEX)
+	{
+		scroll_to_focus();
+		if(state&FOCUS)
+			set_input_focus(items[focus_index].get());
+	}
 }
 
-void List::button_press(int x, int y, unsigned btn)
+void List::item_autosize_changed(Item *item)
+{
+	item->autosize();
+	signal_autosize_changed.emit();
+	mark_rebuild();
+}
+
+void List::reposition_items(bool record_rows)
 {
-	Container::button_press(x, y, btn);
-	if(!click_focus && btn==1)
+	if(!items_part)
+		return;
+
+	if(record_rows)
 	{
-		if(items_part)
-			y += items_part->get_margin().top;
+		rows.clear();
+		rows.push_back(0);
+	}
 
-		unsigned i = (geom.h-1-y)/row_height;
-		if(i<n_visible && first+i<items.size())
+	const Sides &margin = items_part->get_margin();
+	unsigned view_w = geom.w-min(geom.w, margin.left+margin.right);
+	unsigned x = 0;
+	unsigned y = 0;
+	unsigned row_h = 0;
+	for(size_t i=0; i<items.size(); ++i)
+	{
+		const Geometry &igeom = items[i]->get_geometry();
+
+		if(view_mode!=GRID || (x>0 && x+igeom.w>view_w))
 		{
-			sel_index = first+i;
+			x = 0;
+			if(y)
+				y -= row_h;
+			if(record_rows && i>0)
+			{
+				rows.back().height = row_h;
+				rows.push_back(i);
+			}
+			row_h = 0;
+		}
+
+		if(first_row<rows.size() && i==rows[first_row].first)
+			y = geom.h-min(geom.h, margin.top);
 
-			signal_item_selected.emit(sel_index, items[sel_index]);
-			rebuild();
+		if(!y)
+			items[i]->set_visible(false);
+		else if(igeom.h+margin.bottom<=y)
+		{
+			items[i]->set_visible(true);
+			unsigned iw = (view_mode==GRID ? igeom.w : view_w);
+			items[i]->set_geometry(Geometry(margin.left+x, y-igeom.h, iw, igeom.h));
+		}
+		else
+		{
+			for(size_t j=rows.back().first; j<=i; ++j)
+				items[j]->set_visible(false);
+			y = 0;
 		}
+
+		x += igeom.w;
+		row_h = max(row_h, igeom.h);
 	}
+
+	if(record_rows)
+		rows.back().height = row_h;
 }
 
-void List::on_geometry_change()
+size_t List::last_to_first_row(size_t last) const
 {
-	reposition_slider();
+	if(!items_part)
+		return last;
+
+	const Sides &margin = items_part->get_margin();
+	unsigned view_h = geom.h-min(geom.h, margin.top+margin.bottom);
 
-	check_view_range();
+	unsigned items_h = 0;
+	for(size_t i=last; i<rows.size(); --i)
+	{
+		items_h += rows[i].height;
+		if(items_h>view_h)
+			return min(i+1, last);
+	}
+
+	return 0;
 }
 
-void List::on_style_change()
+size_t List::item_index_to_row(size_t index) const
+{
+	for(size_t i=0; i+1<rows.size(); ++i)
+		if(rows[i+1].first>index)
+			return i;
+	return rows.size()-1;
+}
+
+void List::check_view_range()
 {
 	if(!style)
-	{
-		items_part = 0;
 		return;
-	}
 
-	reposition_slider();
+	if(items.empty())
+		max_scroll = 0;
+	else
+		max_scroll = last_to_first_row(rows.size()-1);
 
-	items_part = style->get_part("items");
+	if(first_row>max_scroll)
+		first_row = max_scroll;
 
-	const GL::Font &font = style->get_font();
-	row_height = static_cast<unsigned>((font.get_ascent()-font.get_descent())*style->get_font_size());
+	slider.set_range(0, max_scroll);
+	slider.set_page_size(rows.size()-max_scroll);
+	slider.set_value(max_scroll-first_row);
+}
+
+void List::scroll_to_focus()
+{
+	if(focus_index==INVALID_INDEX || items[focus_index]->is_visible())
+		return;
 
-	check_view_range();
+	size_t focus_row = item_index_to_row(focus_index);
+	if(focus_row<first_row)
+		slider.set_value(max_scroll-focus_row);
+	else
+		slider.set_value(max_scroll-last_to_first_row(focus_row));
 }
 
-void List::reposition_slider()
+void List::slider_value_changed(double value)
 {
-	if(!style)
+	if(max_scroll>0 && !ignore_slider_change)
+	{
+		first_row = max_scroll-static_cast<size_t>(value);
+		mark_rebuild();
+	}
+}
+
+void List::adjust_index(size_t &index, size_t pos, ptrdiff_t change)
+{
+	if(index==INVALID_INDEX)
 		return;
+	else if(index>pos)
+		index += change;
+	else if(index==pos)
+		index = (change>0 ? index+change : INVALID_INDEX);
+}
+
+
+List::DataObserver::DataObserver(List &l):
+	list(l)
+{
+	list.data->signal_item_added.connect(sigc::mem_fun(this, &DataObserver::item_added));
+	list.data->signal_item_removed.connect(sigc::mem_fun(this, &DataObserver::item_removed));
+	list.data->signal_cleared.connect(sigc::mem_fun(this, &DataObserver::cleared));
+	list.data->signal_refresh_item.connect(sigc::mem_fun(this, &DataObserver::refresh_item));
+}
+
+void List::DataObserver::item_added(size_t i)
+{
+	adjust_index(list.sel_index, i, 1);
+	adjust_index(list.focus_index, i, 1);
+
+	list.items.insert(list.items.begin()+i, list.create_item(i));
+	list.items_changed();
+}
+
+void List::DataObserver::item_removed(size_t i)
+{
+	bool had_selection = (list.sel_index!=INVALID_INDEX);
+	adjust_index(list.sel_index, i, -1);
+	adjust_index(list.focus_index, i, -1);
+
+	list.items.erase(list.items.begin()+i);
+	list.items_changed();
 
-	if(const Part *slider_part = style->get_part("slider"))
+	if(had_selection && list.sel_index==INVALID_INDEX)
+		list.signal_selection_cleared.emit();
+}
+
+void List::DataObserver::cleared()
+{
+	list.sel_index = INVALID_INDEX;
+	list.focus_index = INVALID_INDEX;
+	list.items.clear();
+	list.items_changed();
+
+	list.signal_selection_cleared.emit();
+}
+
+void List::DataObserver::refresh_item(size_t i)
+{
+	// Destroy the old item before calling create_item
+	list.items[i].reset();
+	list.items[i] = list.create_item(i);
+	list.items_changed();
+}
+
+
+List::Item::Item()
+{
+	input_type = INPUT_NAVIGATION;
+}
+
+void List::Item::autosize_special(const Part &part, Geometry &ageom) const
+{
+	if(part.get_name()=="children")
 	{
-		Geometry sgeom = slider_part->get_geometry();
-		slider_part->get_alignment().apply(sgeom, geom, slider_part->get_margin());
-		slider.set_geometry(sgeom);
+		const Sides &margin = part.get_margin();
+		for(const unique_ptr<Child> &c: children)
+		{
+			Geometry cgeom;
+			c->widget->autosize(cgeom);
+			ageom.w = max(ageom.w, cgeom.x+cgeom.w+margin.right);
+			ageom.h = max(ageom.h, cgeom.y+cgeom.h+margin.top);
+		}
 	}
 }
 
-void List::check_view_range()
+void List::Item::set_active(bool a)
+{
+	set_state(ACTIVE, (a ? ACTIVE : NORMAL));
+}
+
+void List::Item::render_special(const Part &part, GL::Renderer &renderer) const
 {
-	unsigned h = geom.h;
-	if(items_part)
+	if(part.get_name()=="children")
 	{
-		const Sides &margin = items_part->get_margin();
-		h -= margin.top+margin.bottom;
+		for(const unique_ptr<Child> &c: children)
+			c->widget->render(renderer);
 	}
+}
+
 
-	n_visible = h/row_height;
+void List::SimpleItem::on_style_change()
+{
+	if(!style || children.empty())
+		return;
 
-	if(first+n_visible>items.size())
+	Widget *child = children.front()->widget;
+	child->autosize();
+	if(const Part *part = style->find_part("children"))
 	{
-		if(items.size()>n_visible)
-			first = items.size()-n_visible;
-		else
-			first = 0;
+		const Sides &margin = part->get_margin();
+		child->set_position(margin.left, margin.bottom);
 	}
+}
+
 
-	if(items.size()>n_visible)
+void List::MultiColumnItem::check_widths(vector<unsigned> &widths) const
+{
+	if(widths.size()<children.size())
+		widths.resize(children.size(), 0);
+
+	size_t n = 0;
+	for(const unique_ptr<Child> &c: children)
 	{
-		slider.set_range(0, items.size()-n_visible);
-		slider.set_value(items.size()-n_visible-first);
+		Geometry cgeom;
+		c->widget->autosize(cgeom);
+		// TODO invent a better way to specify spacings
+		widths[n] = max(widths[n], cgeom.w+8);
+		++n;
 	}
-	else
+}
+
+void List::MultiColumnItem::set_widths(const vector<unsigned> &widths)
+{
+	if(!style)
+		return;
+
+	const Part *part = style->find_part("children");
+	if(!part)
+		return;
+
+	const Sides &margin = part->get_margin();
+	int x = margin.left;
+	size_t n = 0;
+	for(const unique_ptr<Child> &c: children)
 	{
-		slider.set_range(0, 0);
-		slider.set_value(0);
+		c->widget->set_position(x, margin.bottom);
+		x += widths[n++];
 	}
 }
 
-void List::slider_value_changed(double value)
+void List::MultiColumnItem::on_style_change()
 {
-	if(items.size()>n_visible)
+	if(!style)
+		return;
+
+	for(const unique_ptr<Child> &c: children)
+		c->widget->autosize();
+
+	vector<unsigned> widths;
+	List *list = static_cast<List *>(parent);
+	for(const unique_ptr<Item> &i: list->items)
+		if(i.get()!=this)
+			if(MultiColumnItem *mci = dynamic_cast<MultiColumnItem *>(i.get()))
+				mci->check_widths(widths);
+
+	vector<unsigned> self_widths(widths);
+	check_widths(self_widths);
+	bool update_all = false;
+	for(size_t i=0; (!update_all && i<widths.size() && i<self_widths.size()); ++i)
+		update_all = self_widths[i]>widths[i];
+
+	if(update_all)
 	{
-		first = items.size()-n_visible-static_cast<unsigned>(value);
-		rebuild();
+		for(const unique_ptr<Item> &i: list->items)
+			if(MultiColumnItem *mci = dynamic_cast<MultiColumnItem *>(i.get()))
+				mci->set_widths(self_widths);
 	}
+
+	set_widths(self_widths);
+}
+
+
+List::BasicItem::BasicItem(const string &text):
+	label(text)
+{
+	add(label);
 }
 
 
 List::Loader::Loader(List &l):
-	Widget::Loader(l)
+	DataFile::DerivedObjectLoader<List, Widget::Loader>(l)
 {
 	add("item", &Loader::item);
+	add("view_mode", &List::view_mode);
+	add("view_size", &List::view_rows);
+	add("view_size", &List::view_rows, &List::view_columns);
 }
 
 void List::Loader::item(const string &v)
 {
-	dynamic_cast<List &>(obj).append(v);
+	dynamic_cast<BasicListData<string> &>(*obj.data).append(v);
+}
+
+
+void operator>>(const LexicalConverter &conv, List::ViewMode &vm)
+{
+	const string &str = conv.get();
+	if(str=="LIST")
+		vm = List::LIST;
+	else if(str=="GRID")
+		vm = List::GRID;
+	else
+		throw lexical_error(format("conversion of '%s' to List::ViewMode", str));
 }
 
 } // namespace GLtk