From 705630e7d09a2c6b80631186f597671a8db5e34b Mon Sep 17 00:00:00 2001
From: DS-Minetest <vorunbekannt75@web.de>
Date: Thu, 25 Jul 2019 15:16:49 +0200
Subject: [PATCH] guiScrollBar: move directly to clicked pos if clicked into
 tray

---
 src/gui/guiScrollBar.cpp | 59 ++++++++++++++--------------------------
 src/gui/guiScrollBar.h   |  4 +--
 2 files changed, 22 insertions(+), 41 deletions(-)

diff --git a/src/gui/guiScrollBar.cpp b/src/gui/guiScrollBar.cpp
index 40c15d639..ea072aa9e 100644
--- a/src/gui/guiScrollBar.cpp
+++ b/src/gui/guiScrollBar.cpp
@@ -21,8 +21,7 @@ guiScrollBar::guiScrollBar(IGUIEnvironment *environment, IGUIElement *parent, s3
 		is_horizontal(horizontal), is_auto_scaling(auto_scale),
 		dragged_by_slider(false), tray_clicked(false), scroll_pos(0),
 		draw_center(0), thumb_size(0), min_pos(0), max_pos(100), small_step(10),
-		large_step(50), desired_pos(0), last_change(0), drag_offset(0),
-		page_size(100), border_size(0)
+		large_step(50), last_change(0), drag_offset(0), page_size(100), border_size(0)
 {
 	refreshControls();
 	setNotClipped(false);
@@ -116,12 +115,25 @@ bool guiScrollBar::OnEvent(const SEvent &event)
 				if (is_inside) {
 					is_dragging = true;
 					dragged_by_slider = slider_rect.isPointInside(p);
-					core::vector2di corner =
-							slider_rect.UpperLeftCorner;
-					drag_offset = is_horizontal ? p.X - corner.X
-								    : p.Y - corner.Y;
+					core::vector2di corner = slider_rect.UpperLeftCorner;
+					drag_offset = is_horizontal ? p.X - corner.X : p.Y - corner.Y;
 					tray_clicked = !dragged_by_slider;
-					desired_pos = getPosFromMousePos(p);
+					if (tray_clicked) {
+						const s32 new_pos = getPosFromMousePos(p);
+						const s32 old_pos = scroll_pos;
+						setPos(new_pos);
+						// drag in the middle
+						drag_offset = thumb_size / 2;
+						// report the scroll event
+						if (scroll_pos != old_pos && Parent) {
+							SEvent e;
+							e.EventType = EET_GUI_EVENT;
+							e.GUIEvent.Caller = this;
+							e.GUIEvent.Element = nullptr;
+							e.GUIEvent.EventType = EGET_SCROLL_BAR_CHANGED;
+							Parent->OnEvent(e);
+						}
+					}
 					Environment->setFocus(this);
 					return true;
 				}
@@ -158,10 +170,7 @@ bool guiScrollBar::OnEvent(const SEvent &event)
 				const s32 new_pos = getPosFromMousePos(p);
 				const s32 old_pos = scroll_pos;
 
-				if (dragged_by_slider)
-					setPos(new_pos);
-				else
-					desired_pos = new_pos;
+				setPos(new_pos);
 
 				if (scroll_pos != old_pos && Parent) {
 					SEvent e;
@@ -184,32 +193,6 @@ bool guiScrollBar::OnEvent(const SEvent &event)
 	return IGUIElement::OnEvent(event);
 }
 
-void guiScrollBar::OnPostRender(u32 timeMs)
-{
-	if (is_dragging && !dragged_by_slider && tray_clicked &&
-			timeMs > last_change + 200) {
-		last_change = timeMs;
-		const s32 old_pos = scroll_pos;
-
-		if (desired_pos >= scroll_pos + large_step)
-			setPos(scroll_pos + large_step);
-		else if (desired_pos <= scroll_pos - large_step)
-			setPos(scroll_pos - large_step);
-		else if (desired_pos >= scroll_pos - large_step &&
-				desired_pos <= scroll_pos + large_step)
-			setPos(desired_pos);
-
-		if (scroll_pos != old_pos && Parent) {
-			SEvent e;
-			e.EventType = EET_GUI_EVENT;
-			e.GUIEvent.Caller = this;
-			e.GUIEvent.Element = nullptr;
-			e.GUIEvent.EventType = EGET_SCROLL_BAR_CHANGED;
-			Parent->OnEvent(e);
-		}
-	}
-}
-
 void guiScrollBar::draw()
 {
 	if (!IsVisible)
@@ -439,4 +422,4 @@ void guiScrollBar::refreshControls()
 	bool visible = (border_size != 0);
 	up_button->setVisible(visible);
 	down_button->setVisible(visible);
-}
\ No newline at end of file
+}
diff --git a/src/gui/guiScrollBar.h b/src/gui/guiScrollBar.h
index be392bc00..2236ff5b9 100644
--- a/src/gui/guiScrollBar.h
+++ b/src/gui/guiScrollBar.h
@@ -26,7 +26,6 @@ public:
 	virtual void draw();
 	virtual void updateAbsolutePosition();
 	virtual bool OnEvent(const SEvent &event);
-	virtual void OnPostRender(u32 timeMs);
 
 	s32 getMax() const { return max_pos; }
 	s32 getMin() const { return min_pos; }
@@ -60,7 +59,6 @@ private:
 	s32 max_pos;
 	s32 small_step;
 	s32 large_step;
-	s32 desired_pos;
 	u32 last_change;
 	s32 drag_offset;
 	s32 page_size;
@@ -68,4 +66,4 @@ private:
 
 	core::rect<s32> slider_rect;
 	video::SColor current_icon_color;
-};
\ No newline at end of file
+};