From ad53fdd7a4450b1971fbe94a14814634a48bf9b5 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Mon, 7 Mar 2022 01:13:13 +0300
Subject: [PATCH] Support ui::scroller preferred direction

---
 libs/ui/include/psemek/ui/scroller.hpp | 11 +++++++
 libs/ui/source/scroller.cpp            | 43 ++++++++++++++------------
 2 files changed, 34 insertions(+), 20 deletions(-)

diff --git a/libs/ui/include/psemek/ui/scroller.hpp b/libs/ui/include/psemek/ui/scroller.hpp
index 32bb5b87..debcc3bb 100644
--- a/libs/ui/include/psemek/ui/scroller.hpp
+++ b/libs/ui/include/psemek/ui/scroller.hpp
@@ -13,6 +13,15 @@ namespace psemek::ui
 
 		virtual std::shared_ptr<element> set_child(std::shared_ptr<element> c);
 
+		enum class direction
+		{
+			horizontal,
+			vertical,
+		};
+
+		virtual direction preferred_direction() const { return preferred_direction_; }
+		virtual void set_preferred_direction(direction d);
+
 		virtual bool set_horizontal_scroll(bool enabled);
 		virtual bool set_vertical_scroll(bool enabled);
 
@@ -57,6 +66,8 @@ namespace psemek::ui
 		box_shape shape_;
 		std::optional<geom::point<int, 2>> mouse_;
 
+		direction preferred_direction_ = direction::vertical;
+
 		bool horizontal_ = false;
 		bool vertical_ = true;
 
diff --git a/libs/ui/source/scroller.cpp b/libs/ui/source/scroller.cpp
index 635afb73..6487d4b4 100644
--- a/libs/ui/source/scroller.cpp
+++ b/libs/ui/source/scroller.cpp
@@ -17,6 +17,11 @@ namespace psemek::ui
 		return old;
 	}
 
+	void scroller::set_preferred_direction(direction d)
+	{
+		preferred_direction_ = d;
+	}
+
 	bool scroller::set_horizontal_scroll(bool enabled)
 	{
 		std::swap(horizontal_, enabled);
@@ -164,32 +169,30 @@ namespace psemek::ui
 		{
 			geom::vector<float, 2> delta = {0.f, 0.f};
 
-			if (vertical_scroll() && !horizontal_scroll())
+			auto pos = geom::cast<float>(*mouse_);
+
+			auto vcontains = geom::contains(vertical_box(), pos);
+			auto hcontains = geom::contains(horizontal_box(), pos);
+
+			if (vertical_scroll() && horizontal_scroll())
+			{
+				if (vcontains)
+					delta[1] = e.delta;
+				else if (hcontains)
+					delta[0] = e.delta;
+				else if (preferred_direction() == direction::vertical)
+					delta[1] = e.delta;
+				else
+					delta[0] = e.delta;
+			}
+			else if (vertical_scroll())
 			{
 				delta[1] = e.delta;
 			}
-			else if (!vertical_scroll() && horizontal_scroll())
+			else if (horizontal_scroll())
 			{
 				delta[0] = e.delta;
 			}
-			else
-			{
-				auto pos = geom::cast<float>(*mouse_);
-
-				if (horizontal_scroll())
-				{
-					if (geom::contains(horizontal_box(), pos))
-					{
-						delta[0] = e.delta;
-					}
-				}
-
-				if (vertical_scroll())
-				{
-					if (geom::contains(vertical_box(), pos))
-						delta[1] = e.delta;
-				}
-			}
 
 			shift_tgt_ += delta * 50.f;
 			clamp_shift();