From 5f73de83d46138faa2b4c1b0a725d0a705988388 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 24 Sep 2019 01:26:30 +0300
Subject: [PATCH] Add a page size feature to Slider

---
 source/entry.cpp  |  1 +
 source/list.cpp   |  1 +
 source/slider.cpp | 33 +++++++++++++++++++++++++++------
 source/slider.h   |  3 +++
 4 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/source/entry.cpp b/source/entry.cpp
index 83ed563..4c1713a 100644
--- a/source/entry.cpp
+++ b/source/entry.cpp
@@ -487,6 +487,7 @@ void Entry::check_view_range()
 		signal_scroll_position_changed.emit(first_row);
 
 	slider->set_range(0, scroll);
+	slider->set_page_size(visible_rows);
 	slider->set_value(scroll-first_row);
 }
 
diff --git a/source/list.cpp b/source/list.cpp
index 13a5619..a7185ac 100644
--- a/source/list.cpp
+++ b/source/list.cpp
@@ -506,6 +506,7 @@ void List::check_view_range()
 		first_row = max_scroll;
 
 	slider.set_range(0, max_scroll);
+	slider.set_page_size(rows.size()-max_scroll);
 	slider.set_value(max_scroll-first_row);
 }
 
diff --git a/source/slider.cpp b/source/slider.cpp
index 8ff342d..70798af 100644
--- a/source/slider.cpp
+++ b/source/slider.cpp
@@ -14,9 +14,11 @@ Slider::Slider(Direction d):
 	max(1),
 	value(0),
 	step(0.1),
+	page_size(0.25),
 	dragging(false),
 	drag_area_size(0),
 	drag_area_offset(0),
+	slider_min_size(1),
 	slider_size(1),
 	total_margin(0)
 { }
@@ -55,6 +57,12 @@ void Slider::set_step(double s)
 	set_value(value);
 }
 
+void Slider::set_page_size(double p)
+{
+	page_size = p;
+	mark_rebuild();
+}
+
 void Slider::autosize_special(const Part &part, Geometry &ageom) const
 {
 	if(part.get_name()=="slider")
@@ -75,18 +83,30 @@ void Slider::rebuild_special(const Part &part)
 			return;
 
 		float pos_fraction = ((max>min) ? (value-min)/(max-min) : 0);
+		float fill_fraction = ((max>min) ? page_size/(max-min+page_size) : 1);
 
 		Alignment align = part.get_alignment();
+		Geometry sgeom = geom;
 		if(dir==HORIZONTAL)
+		{
 			align.x = pos_fraction;
+			sgeom.w = std::max(slider_min_size+total_margin, static_cast<unsigned>(sgeom.w*fill_fraction));
+		}
 		else
+		{
 			align.y = pos_fraction;
+			sgeom.h = std::max(slider_min_size+total_margin, static_cast<unsigned>(sgeom.h*fill_fraction));
+		}
+
+		sgeom.x = static_cast<unsigned>((geom.w-sgeom.w)*pos_fraction);
+		sgeom.y = static_cast<unsigned>((geom.h-sgeom.h)*pos_fraction);
 
 		Geometry rgeom = part.get_geometry();
-		align.apply(rgeom, geom, part.get_margin());
+		align.apply(rgeom, sgeom, part.get_margin());
+		slider_size = (dir==HORIZONTAL ? rgeom.w : rgeom.h);
 
 		GL::MeshBuilder bld(part_cache.create_mesh(part, *graphic->get_texture()));
-		bld.matrix() *= GL::Matrix::translation(rgeom.x, rgeom.y, 0);
+		bld.matrix() *= GL::Matrix::translation(sgeom.x+rgeom.x, sgeom.y+rgeom.y, 0);
 		graphic->build(rgeom.w, rgeom.h, bld);
 	}
 }
@@ -104,9 +124,9 @@ void Slider::button_press(int x, int y, unsigned btn)
 
 	int sp = static_cast<int>((drag_area_size-slider_size)*(value-min)/(max-min));
 	if(p<sp)
-		set_value(value-step*10);
+		set_value(value-page_size);
 	else if(p>=static_cast<int>(sp+slider_size))
-		set_value(value+step*10);
+		set_value(value+page_size);
 	else
 	{
 		dragging = true;
@@ -150,13 +170,13 @@ void Slider::on_style_change()
 		const Sides &margin = slider_part->get_margin();
 		if(dir==HORIZONTAL)
 		{
-			slider_size = pgeom.w;
+			slider_min_size = pgeom.w;
 			drag_area_offset = margin.left;
 			total_margin = margin.left+margin.right;
 		}
 		else
 		{
-			slider_size = pgeom.h;
+			slider_min_size = pgeom.h;
 			drag_area_offset = margin.bottom;
 			total_margin = margin.bottom+margin.top;
 		}
@@ -171,6 +191,7 @@ Slider::Loader::Loader(Slider &s):
 {
 	add("range", &Slider::min, &Slider::max);
 	add("step",  &Slider::step);
+	add("page_size", &Slider::page_size);
 	add("value", &Slider::value);
 }
 
diff --git a/source/slider.h b/source/slider.h
index b6041af..4260564 100644
--- a/source/slider.h
+++ b/source/slider.h
@@ -36,12 +36,14 @@ protected:
 	double min, max;
 	double value;
 	double step;
+	double page_size;
 
 	bool dragging;
 	double drag_start_pos;
 	double drag_start_value;
 	unsigned drag_area_size;
 	unsigned drag_area_offset;
+	unsigned slider_min_size;
 	unsigned slider_size;
 	unsigned total_margin;
 
@@ -51,6 +53,7 @@ public:
 	void set_value(double);
 	void set_range(double, double);
 	void set_step(double);
+	void set_page_size(double);
 	double get_value() const { return value; }
 
 protected:
-- 
2.43.0