From 1c286139814c339b812a6995c1690312618d78f8 Mon Sep 17 00:00:00 2001
From: Sasha Koshka <sashakoshka@tebibyte.media>
Date: Thu, 9 Mar 2023 23:27:08 -0500
Subject: [PATCH] The scroll bar is better

---
 elements/basic/scrollbar.go | 10 ++++++---
 examples/scroll/main.go     | 41 ++++++++++++++++++++++++-------------
 2 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/elements/basic/scrollbar.go b/elements/basic/scrollbar.go
index a820aaa..8f75938 100644
--- a/elements/basic/scrollbar.go
+++ b/elements/basic/scrollbar.go
@@ -70,7 +70,9 @@ func (element *ScrollBar) HandleMouseDown (x, y int, button input.Button) {
 		// the mouse is pressed down within the bar's handle
 		element.dragging   = true
 		element.drawAndPush()
-		element.dragOffset = point
+		element.dragOffset =
+			point.Sub(element.bar.Min).
+			Add(element.Bounds().Min)
 		element.dragTo(point)
 	} else {
 		// the mouse is pressed down within the bar's gutter
@@ -178,9 +180,11 @@ func (element *ScrollBar) isAfterHandle (point image.Point) bool {
 
 func (element *ScrollBar) fallbackDragOffset () image.Point {
 	if element.vertical {
-		return element.bar.Min.Add(image.Pt(0, element.bar.Dy() / 2))
+		return element.Bounds().Min.
+			Add(image.Pt(0, element.bar.Dy() / 2))
 	} else {
-		return element.bar.Min.Add(image.Pt(element.bar.Dx() / 2, 0))
+		return element.Bounds().Min.
+			Add(image.Pt(element.bar.Dx() / 2, 0))
 	}
 }
 
diff --git a/examples/scroll/main.go b/examples/scroll/main.go
index e17c7d2..ae97064 100644
--- a/examples/scroll/main.go
+++ b/examples/scroll/main.go
@@ -24,17 +24,27 @@ func run () {
 		Gap: true,
 	})
 	list := basicElements.NewList (
-		basicElements.NewListEntry("something", nil),
-		basicElements.NewListEntry("something", nil),
-		basicElements.NewListEntry("something", nil),
-		basicElements.NewListEntry("something", nil),
-		basicElements.NewListEntry("something", nil),
-		basicElements.NewListEntry("something", nil),
-		basicElements.NewListEntry("something", nil),
-		basicElements.NewListEntry("something", nil),
-		basicElements.NewListEntry("something", nil),
-		basicElements.NewListEntry("something", nil),
-		basicElements.NewListEntry("something", nil))
+		basicElements.NewListEntry("This is list item 0", nil),
+		basicElements.NewListEntry("This is list item 1", nil),
+		basicElements.NewListEntry("This is list item 2", nil),
+		basicElements.NewListEntry("This is list item 3", nil),
+		basicElements.NewListEntry("This is list item 4", nil),
+		basicElements.NewListEntry("This is list item 5", nil),
+		basicElements.NewListEntry("This is list item 6", nil),
+		basicElements.NewListEntry("This is list item 7", nil),
+		basicElements.NewListEntry("This is list item 8", nil),
+		basicElements.NewListEntry("This is list item 9", nil),
+		basicElements.NewListEntry("This is list item 10", nil),
+		basicElements.NewListEntry("This is list item 11", nil),
+		basicElements.NewListEntry("This is list item 12", nil),
+		basicElements.NewListEntry("This is list item 13", nil),
+		basicElements.NewListEntry("This is list item 14", nil),
+		basicElements.NewListEntry("This is list item 15", nil),
+		basicElements.NewListEntry("This is list item 16", nil),
+		basicElements.NewListEntry("This is list item 17", nil),
+		basicElements.NewListEntry("This is list item 18", nil),
+		basicElements.NewListEntry("This is list item 19", nil),
+		basicElements.NewListEntry("This is list item 20", nil))
 	list.Collapse(0, 32)
 	scrollBar := basicElements.NewScrollBar(true)
 	list.OnScrollBoundsChange (func () {
@@ -46,12 +56,15 @@ func run () {
 		list.ScrollTo(viewport)
 	})
 	
-	container.Adopt(basicElements.NewLabel("look at this non sense", false), false)
+	container.Adopt(basicElements.NewLabel("A ScrollContainer:", false), false)
 	scrollContainer.Adopt(textBox)
 	container.Adopt(scrollContainer, false)
-	container.Adopt(basicElements.NewLabel("what does that scrollbar do?", false), false)
 	disconnectedContainer.Adopt(list, false)
-	disconnectedContainer.Adopt(basicElements.NewSpacer(true), true)
+	disconnectedContainer.Adopt (basicElements.NewLabel (
+		"Notice how the scroll bar to the right can be used to " +
+		"control the list, despite not even touching it. It is " +
+		"indeed a thing you can do. It is also terrible UI design so " +
+		"don't do it.", true), true)
 	disconnectedContainer.Adopt(scrollBar, false)
 	container.Adopt(disconnectedContainer, true)