From 8a94058d44e1152e27288fd777ad407faae22784 Mon Sep 17 00:00:00 2001
From: vsariola <5684185+vsariola@users.noreply.github.com>
Date: Wed, 12 May 2021 23:14:48 +0300
Subject: [PATCH] feat(gioui): make split bars snap to window edges

---
 tracker/gioui/split.go | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tracker/gioui/split.go b/tracker/gioui/split.go
index 1211ab0..d7a526f 100644
--- a/tracker/gioui/split.go
+++ b/tracker/gioui/split.go
@@ -68,6 +68,7 @@ func (s *Split) Layout(gtx layout.Context, first, second layout.Widget) layout.D
 				} else {
 					s.dragCoord = e.Position.Y
 				}
+				s.drag = true
 
 			case pointer.Drag:
 				if s.dragID != e.PointerID {
@@ -94,6 +95,27 @@ func (s *Split) Layout(gtx layout.Context, first, second layout.Widget) layout.D
 			}
 		}
 
+		low := -1 + float32(bar)/float32(coord)*2
+		const snapMargin = 0.1
+
+		if s.Ratio < low {
+			s.Ratio = low
+		}
+
+		if s.Ratio > 1 {
+			s.Ratio = 1
+		}
+
+		if s.Ratio < low+snapMargin {
+			firstSize = 0
+			secondOffset = bar
+			secondSize = coord - bar
+		} else if s.Ratio > 1-snapMargin {
+			firstSize = coord - bar
+			secondOffset = coord
+			secondSize = 0
+		}
+
 		// register for input
 		var barRect image.Rectangle
 		if s.Axis == layout.Horizontal {