From 878faa0c9283ee1e6e5e67b6ea1324cc52385742 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 23 Sep 2019 23:59:24 +0300
Subject: [PATCH] Defer widget rebuild to just before they are rendered

This improves performance especially with complex widgets like Entry.
---
 source/button.cpp    |  4 ++--
 source/container.cpp | 23 ++++++++++++++++++++++-
 source/container.h   |  5 +++++
 source/dropdown.cpp  |  2 +-
 source/entry.cpp     | 12 ++++++------
 source/image.cpp     |  6 +++---
 source/label.cpp     |  2 +-
 source/list.cpp      |  6 +++---
 source/root.cpp      |  9 ++++++++-
 source/root.h        |  3 ++-
 source/slider.cpp    |  2 +-
 source/toggle.cpp    |  2 +-
 source/widget.cpp    | 24 +++++++++++++++++++++---
 source/widget.h      |  4 ++++
 14 files changed, 80 insertions(+), 24 deletions(-)

diff --git a/source/button.cpp b/source/button.cpp
index fadd00a..abdc1f6 100644
--- a/source/button.cpp
+++ b/source/button.cpp
@@ -33,13 +33,13 @@ void Button::set_text(const std::string &t)
 {
 	text = t;
 	signal_autosize_changed.emit();
-	rebuild();
+	mark_rebuild();
 }
 
 void Button::set_icon(const GL::Texture2D *i)
 {
 	icon = i;
-	rebuild();
+	mark_rebuild();
 }
 
 void Button::rebuild_special(const Part &part)
diff --git a/source/container.cpp b/source/container.cpp
index e99d993..28e0e2f 100644
--- a/source/container.cpp
+++ b/source/container.cpp
@@ -18,7 +18,8 @@ Container::Container():
 	pointer_grabbed(false),
 	input_focus(0),
 	saved_input_focus(0),
-	touch_focus(0)
+	touch_focus(0),
+	children_rebuild_needed(false)
 { }
 
 Container::~Container()
@@ -33,6 +34,7 @@ void Container::add(Widget &wdg)
 	children.push_back(create_child(&wdg));
 	if(wdg.get_animation_interval())
 		check_animation_interval();
+	children_rebuild_needed = true;
 	on_child_added(wdg);
 }
 
@@ -185,6 +187,18 @@ void Container::check_animation_interval()
 		set_animation_interval(shortest);
 }
 
+void Container::rebuild_hierarchy()
+{
+	Widget::rebuild_hierarchy();
+
+	if(children_rebuild_needed)
+	{
+		children_rebuild_needed = false;
+		for(list<Child *>::iterator i=children.begin(); i!=children.end(); ++i)
+			(*i)->widget->rebuild_hierarchy();
+	}
+}
+
 void Container::button_press(int x, int y, unsigned btn)
 {
 	if(Widget *child = get_pointer_target(x, y, false))
@@ -382,6 +396,7 @@ Container::Child::Child(Container &c, Widget *w):
 	widget->signal_grab_pointer.connect(sigc::mem_fun(this, &Child::grab_pointer));
 	widget->signal_ungrab_pointer.connect(sigc::mem_fun(this, &Child::ungrab_pointer));
 	widget->signal_request_animation.connect(sigc::mem_fun(this, &Child::request_animation));
+	widget->signal_rebuild_needed.connect(sigc::mem_fun(this, &Child::rebuild_needed));
 }
 
 Container::Child::~Child()
@@ -436,5 +451,11 @@ void Container::Child::request_animation(const Time::TimeDelta &interval)
 	container.check_animation_interval();
 }
 
+void Container::Child::rebuild_needed()
+{
+	container.children_rebuild_needed = true;
+	container.signal_rebuild_needed.emit();
+}
+
 } // namespace GLtk
 } // namespace Msp
diff --git a/source/container.h b/source/container.h
index d98ce39..a80cc4e 100644
--- a/source/container.h
+++ b/source/container.h
@@ -34,6 +34,7 @@ protected:
 		void grab_pointer();
 		void ungrab_pointer();
 		void request_animation(const Time::TimeDelta &);
+		void rebuild_needed();
 	};
 
 	std::list<Child *> children;
@@ -44,6 +45,7 @@ protected:
 	Widget *input_focus;
 	Widget *saved_input_focus;
 	Widget *touch_focus;
+	bool children_rebuild_needed;
 
 	Container();
 public:
@@ -72,6 +74,9 @@ public:
 private:
 	void check_animation_interval();
 
+protected:
+	virtual void rebuild_hierarchy();
+
 public:
 	virtual void button_press(int, int, unsigned);
 	virtual void button_release(int, int, unsigned);
diff --git a/source/dropdown.cpp b/source/dropdown.cpp
index f922001..1084612 100644
--- a/source/dropdown.cpp
+++ b/source/dropdown.cpp
@@ -191,7 +191,7 @@ void Dropdown::list_item_selected(unsigned index)
 	text.set(list.get_data().get_string(index));
 
 	signal_item_selected.emit(index);
-	rebuild();
+	mark_rebuild();
 }
 
 void Dropdown::list_selection_cleared()
diff --git a/source/entry.cpp b/source/entry.cpp
index b00fc6b..ed0d7e2 100644
--- a/source/entry.cpp
+++ b/source/entry.cpp
@@ -84,7 +84,7 @@ void Entry::insert(unsigned pos, const string &t)
 	if(multiline)
 		check_view_range();
 
-	rebuild();
+	mark_rebuild();
 }
 
 void Entry::erase(unsigned pos, unsigned len)
@@ -114,7 +114,7 @@ void Entry::erase(unsigned pos, unsigned len)
 	if(multiline)
 		check_view_range();
 
-	rebuild();
+	mark_rebuild();
 }
 
 bool Entry::get_selection(unsigned &start, unsigned &end) const
@@ -158,7 +158,7 @@ void Entry::set_multiline(bool m)
 			add(*slider);
 			slider->set_step(1);
 			slider->signal_value_changed.connect(sigc::mem_fun(this, &Entry::slider_value_changed));
-			rebuild();
+			mark_rebuild();
 		}
 		check_view_range();
 	}
@@ -366,7 +366,7 @@ bool Entry::navigate(Navigation nav)
 void Entry::animate(const Time::TimeDelta &)
 {
 	cursor_blink = !cursor_blink;
-	rebuild();
+	mark_rebuild();
 }
 
 void Entry::on_size_change()
@@ -429,7 +429,7 @@ void Entry::set_edit_position(unsigned ep, bool select)
 
 	if(multiline)
 		check_view_range();
-	rebuild();
+	mark_rebuild();
 }
 
 void Entry::erase_selection(bool emit_change)
@@ -495,7 +495,7 @@ void Entry::slider_value_changed(double value)
 		first_row = text.get_n_lines()-visible_rows-static_cast<unsigned>(value);
 		if(first_row!=old_first_row)
 			signal_scroll_position_changed.emit(first_row);
-		rebuild();
+		mark_rebuild();
 	}
 }
 
diff --git a/source/image.cpp b/source/image.cpp
index 1da782d..bc91856 100644
--- a/source/image.cpp
+++ b/source/image.cpp
@@ -39,7 +39,7 @@ void Image::set_image(const GL::Texture2D *i)
 	image = i;
 	icon_name = string();
 	signal_autosize_changed.emit();
-	rebuild();
+	mark_rebuild();
 }
 
 void Image::set_icon(const string &n)
@@ -51,7 +51,7 @@ void Image::set_icon(const string &n)
 void Image::set_keep_aspect(bool ka)
 {
 	keep_aspect = ka;
-	rebuild();
+	mark_rebuild();
 }
 
 void Image::update_icon()
@@ -66,7 +66,7 @@ void Image::update_icon()
 			else
 				image = &root->get_resources().get<GL::Texture2D>(icon_name);
 			signal_autosize_changed.emit();
-			rebuild();
+			mark_rebuild();
 			return;
 		}
 	}
diff --git a/source/label.cpp b/source/label.cpp
index 263b2a4..033bfd9 100644
--- a/source/label.cpp
+++ b/source/label.cpp
@@ -16,7 +16,7 @@ void Label::set_text(const string &t)
 {
 	text = t;
 	signal_autosize_changed.emit();
-	rebuild();
+	mark_rebuild();
 }
 
 void Label::autosize_special(const Part &part, Geometry &ageom) const
diff --git a/source/list.cpp b/source/list.cpp
index 9eff09b..5493947 100644
--- a/source/list.cpp
+++ b/source/list.cpp
@@ -136,7 +136,7 @@ void List::set_data(ListData &d)
 void List::items_changed()
 {
 	signal_autosize_changed.emit();
-	rebuild();
+	mark_rebuild();
 }
 
 List::Item *List::create_item(unsigned index)
@@ -404,7 +404,7 @@ void List::item_autosize_changed(Item *item)
 {
 	item->autosize();
 	signal_autosize_changed.emit();
-	rebuild();
+	mark_rebuild();
 }
 
 void List::reposition_items(bool record_rows)
@@ -527,7 +527,7 @@ void List::slider_value_changed(double value)
 	if(max_scroll>0 && !ignore_slider_change)
 	{
 		first_row = max_scroll-static_cast<unsigned>(value);
-		rebuild();
+		mark_rebuild();
 	}
 }
 
diff --git a/source/root.cpp b/source/root.cpp
index 7134774..64c7dd5 100644
--- a/source/root.cpp
+++ b/source/root.cpp
@@ -144,8 +144,10 @@ void Root::tick()
 	}
 }
 
-void Root::render() const
+void Root::render()
 {
+	rebuild_hierarchy();
+
 	GL::Bind bind_blend(GL::Blend::alpha());
 
 	GL::Renderer renderer(&camera);
@@ -153,6 +155,11 @@ void Root::render() const
 	Widget::render(renderer);
 }
 
+void Root::setup_frame(GL::Renderer &)
+{
+	rebuild_hierarchy();
+}
+
 void Root::render(GL::Renderer &renderer, const GL::Tag &tag) const
 {
 	if(tag.id)
diff --git a/source/root.h b/source/root.h
index 73ca276..effa556 100644
--- a/source/root.h
+++ b/source/root.h
@@ -64,7 +64,8 @@ public:
 	virtual unsigned get_height() const { return geom.h; }
 
 	void tick();
-	void render() const;
+	void render();
+	virtual void setup_frame(GL::Renderer &);
 	virtual void render(GL::Renderer &, const GL::Tag & = GL::Tag()) const;
 
 private:
diff --git a/source/slider.cpp b/source/slider.cpp
index 1e763c6..5034b24 100644
--- a/source/slider.cpp
+++ b/source/slider.cpp
@@ -31,7 +31,7 @@ void Slider::set_value(double v)
 	if(value!=old_value)
 	{
 		signal_value_changed.emit(value);
-		rebuild();
+		mark_rebuild();
 	}
 }
 
diff --git a/source/toggle.cpp b/source/toggle.cpp
index b0219fc..daacd98 100644
--- a/source/toggle.cpp
+++ b/source/toggle.cpp
@@ -28,7 +28,7 @@ void Toggle::set_text(const string &t)
 {
 	text = t;
 	signal_autosize_changed.emit();
-	rebuild();
+	mark_rebuild();
 }
 
 void Toggle::set_exclusive(bool e)
diff --git a/source/widget.cpp b/source/widget.cpp
index d6d5755..1c73d76 100644
--- a/source/widget.cpp
+++ b/source/widget.cpp
@@ -73,7 +73,7 @@ void Widget::set_geometry(const Geometry &g)
 	if(size_changed)
 	{
 		on_size_change();
-		rebuild();
+		mark_rebuild();
 	}
 }
 
@@ -141,7 +141,7 @@ void Widget::update_style()
 
 	on_style_change();
 	signal_autosize_changed.emit();
-	rebuild();
+	mark_rebuild();
 }
 
 void Widget::set_tooltip(const string &t)
@@ -184,7 +184,7 @@ void Widget::set_state(State mask, State bits)
 	State old_state = state;
 	state = (state&~mask)|bits;
 	if(style && style->compare_states(old_state, state))
-		rebuild();
+		mark_rebuild();
 }
 
 void Widget::set_animation_interval(const Time::TimeDelta &iv)
@@ -201,6 +201,24 @@ void Widget::stop_animation()
 	set_animation_interval(Time::zero);
 }
 
+void Widget::mark_rebuild()
+{
+	if(rebuild_needed)
+		return;
+
+	rebuild_needed = true;
+	signal_rebuild_needed.emit();
+}
+
+void Widget::rebuild_hierarchy()
+{
+	if(rebuild_needed)
+	{
+		rebuild_needed = false;
+		rebuild();
+	}
+}
+
 void Widget::rebuild()
 {
 	if(!style)
diff --git a/source/widget.h b/source/widget.h
index 2e8ef7a..7cbec37 100644
--- a/source/widget.h
+++ b/source/widget.h
@@ -41,6 +41,7 @@ public:
 	sigc::signal<void> signal_grab_pointer;
 	sigc::signal<void> signal_ungrab_pointer;
 	sigc::signal<void, const Time::TimeDelta &> signal_request_animation;
+	sigc::signal<void> signal_rebuild_needed;
 
 protected:
 	Geometry geom;
@@ -52,6 +53,7 @@ protected:
 	Container *parent;
 	std::string tooltip;
 	PartCache part_cache;
+	bool rebuild_needed;
 	Time::TimeDelta anim_interval;
 
 	Widget();
@@ -133,6 +135,8 @@ public:
 	const Time::TimeDelta &get_animation_interval() const { return anim_interval; }
 
 protected:
+	void mark_rebuild();
+	virtual void rebuild_hierarchy();
 	void rebuild();
 	virtual void rebuild_special(const Part &);
 
-- 
2.43.0