Add option to always show scroll bar

CHANGELOG

@@ -1,5 +1,6 @@
 v1.4.3 (WIP)
 - Add SetFocusedFunc to TreeNode
+- Add option to always show scroll bar
 - Do not wrap around list by default
 
 v1.4.2 (2020-02-02)

go.mod

@@ -7,6 +7,6 @@ require (
 	github.com/lucasb-eyer/go-colorful v1.0.3
 	github.com/mattn/go-runewidth v0.0.8
 	github.com/rivo/uniseg v0.1.0
-	golang.org/x/sys v0.0.0-20200124204421-9fbb57f87de9 // indirect
+	golang.org/x/sys v0.0.0-20200212091648-12a6c2dcc1e4 // indirect
 	golang.org/x/text v0.3.2 // indirect
 )

go.sum

@@ -16,10 +16,11 @@ github.com/rivo/uniseg v0.1.0 h1:+2KBaVoUmb9XzDsrx/Ct0W/EYOSFf/nWTauy++DprtY=
 github.com/rivo/uniseg v0.1.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 golang.org/x/sys v0.0.0-20190626150813-e07cf5db2756 h1:9nuHUbU8dRnRRfj9KjWUVrJeoexdbeMjttk6Oh1rD10=
 golang.org/x/sys v0.0.0-20190626150813-e07cf5db2756/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200124204421-9fbb57f87de9 h1:1/DFK4b7JH8DmkqhUk48onnSfrPzImPoVxuomtbT2nk=
-golang.org/x/sys v0.0.0-20200124204421-9fbb57f87de9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200212091648-12a6c2dcc1e4 h1:sfkvUWPNGwSV+8/fNqctR5lS2AqCSqYwXdrjCxp/dXo=
+golang.org/x/sys v0.0.0-20200212091648-12a6c2dcc1e4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e h1:FDhOuMEY4JVRztM/gsbk+IKUQ8kj74bxZrgw87eMMVc=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

list.go

@@ -42,8 +42,8 @@ type List struct {
 	// The text color for selected items.
 	selectedTextColor tcell.Color
 
-	// Whether or not to render a scroll bar.
-	showScrollBar bool
+	// Visibility of the scroll bar.
+	scrollBarVisibility ScrollBarVisibility
 
 	// The scroll bar color.
 	scrollBarColor tcell.Color
@@ -80,7 +80,7 @@ func NewList() *List {
 	return &List{
 		Box:                     NewBox(),
 		showSecondaryText:       true,
-		showScrollBar:           true,
+		scrollBarVisibility:     ScrollBarAuto,
 		mainTextColor:           Styles.PrimaryTextColor,
 		secondaryTextColor:      Styles.TertiaryTextColor,
 		shortcutColor:           Styles.SecondaryTextColor,
@@ -223,10 +223,9 @@ func (l *List) ShowSecondaryText(show bool) *List {
 	return l
 }
 
-// ShowScrollBar determines whether or not to render a scroll bar when there
-// are additional items offscreen.
-func (l *List) ShowScrollBar(show bool) *List {
-	l.showScrollBar = show
+// SetScrollBarVisibility specifies the display of the scroll bar.
+func (l *List) SetScrollBarVisibility(visibility ScrollBarVisibility) *List {
+	l.scrollBarVisibility = visibility
 	return l
 }
 
@@ -489,7 +488,7 @@ func (l *List) Draw(screen tcell.Screen) {
 			}
 		}
 
-		if l.showScrollBar {
+		if l.scrollBarVisibility == ScrollBarAlways || (l.scrollBarVisibility == ScrollBarAuto && len(l.items) > scrollBarHeight) {
 			RenderScrollBar(screen, scrollBarX, y, scrollBarHeight, len(l.items), l.currentItem, index-l.offset, l.hasFocus, l.scrollBarColor)
 		}
 
@@ -503,7 +502,7 @@ func (l *List) Draw(screen tcell.Screen) {
 		if l.showSecondaryText {
 			Print(screen, item.SecondaryText, x, y, width, AlignLeft, l.secondaryTextColor)
 
-			if l.showScrollBar {
+			if l.scrollBarVisibility == ScrollBarAlways || (l.scrollBarVisibility == ScrollBarAuto && len(l.items) > scrollBarHeight) {
 				RenderScrollBar(screen, scrollBarX, y, scrollBarHeight, len(l.items), l.currentItem, index-l.offset, l.hasFocus, l.scrollBarColor)
 			}
 

table.go

@@ -251,8 +251,8 @@ type Table struct {
 	// The number of visible rows the last time the table was drawn.
 	visibleRows int
 
-	// Whether or not to render a scroll bar.
-	showScrollBar bool
+	// Visibility of the scroll bar.
+	scrollBarVisibility ScrollBarVisibility
 
 	// The scroll bar color.
 	scrollBarColor tcell.Color
@@ -279,12 +279,12 @@ type Table struct {
 // NewTable returns a new table.
 func NewTable() *Table {
 	return &Table{
-		Box:            NewBox(),
-		showScrollBar:  true,
-		scrollBarColor: Styles.ScrollBarColor,
-		bordersColor:   Styles.GraphicsColor,
-		separator:      ' ',
-		lastColumn:     -1,
+		Box:                 NewBox(),
+		scrollBarVisibility: ScrollBarAuto,
+		scrollBarColor:      Styles.ScrollBarColor,
+		bordersColor:        Styles.GraphicsColor,
+		separator:           ' ',
+		lastColumn:          -1,
 	}
 }
 
@@ -308,10 +308,9 @@ func (t *Table) SetBordersColor(color tcell.Color) *Table {
 	return t
 }
 
-// ShowScrollBar determines whether or not to render a scroll bar when there
-// are additional rows and/or columns offscreen.
-func (t *Table) ShowScrollBar(show bool) *Table {
-	t.showScrollBar = show
+// SetScrollBarVisibility specifies the display of the scroll bar.
+func (t *Table) SetScrollBarVisibility(visibility ScrollBarVisibility) *Table {
+	t.scrollBarVisibility = visibility
 	return t
 }
 
@@ -591,7 +590,7 @@ func (t *Table) Draw(screen tcell.Screen) {
 		t.visibleRows = height
 	}
 
-	showVerticalScrollBar := t.showScrollBar && len(t.cells) > height
+	showVerticalScrollBar := t.scrollBarVisibility == ScrollBarAlways || (t.scrollBarVisibility == ScrollBarAuto && len(t.cells) > t.visibleRows-t.fixedRows)
 	if showVerticalScrollBar {
 		width-- // Subtract space for scroll bar.
 	}
@@ -792,6 +791,7 @@ ColumnLoop:
 			toDistribute -= expWidth
 			expansionTotal -= expansion
 		}
+		tableWidth = width - toDistribute
 	}
 
 	// Helper function which draws border runes.
@@ -888,13 +888,32 @@ ColumnLoop:
 	}
 
 	if showVerticalScrollBar {
-		// Calculate scroll bar position.
+		// Calculate scroll bar position and dimensions.
 		rows := len(t.cells)
-		cursor := int(float64(rows-t.fixedRows) * (float64(t.rowOffset) / float64(((rows-t.fixedRows)-t.visibleRows)+1)))
+
+		scrollBarItems := rows - t.fixedRows
+		scrollBarHeight := t.visibleRows - t.fixedRows
+
+		scrollBarX := x + width
+		scrollBarY := y + t.fixedRows
+		if scrollBarX > x+tableWidth {
+			scrollBarX = x + tableWidth
+		}
+
+		padTotalOffset := 1
+		if t.borders {
+			padTotalOffset = 2
+
+			scrollBarItems *= 2
+			scrollBarHeight = (scrollBarHeight * 2) - 1
+
+			scrollBarY += t.fixedRows + 1
+		}
 
 		// Draw scroll bar.
-		for printed := 0; printed < (t.visibleRows - t.fixedRows); printed++ {
-			RenderScrollBar(screen, x+width, y+t.fixedRows+printed, t.visibleRows-t.fixedRows, rows-t.fixedRows, cursor, printed, t.hasFocus, t.scrollBarColor)
+		cursor := int(float64(scrollBarItems) * (float64(t.rowOffset) / float64(((rows-t.fixedRows)-t.visibleRows)+padTotalOffset)))
+		for printed := 0; printed < scrollBarHeight; printed++ {
+			RenderScrollBar(screen, scrollBarX, scrollBarY+printed, scrollBarHeight, scrollBarItems, cursor, printed, t.hasFocus, t.scrollBarColor)
 		}
 	}
 

treeview.go

@@ -282,8 +282,8 @@ type TreeView struct {
 	// The color of the lines.
 	graphicsColor tcell.Color
 
-	// Whether or not to render a scroll bar.
-	showScrollBar bool
+	// Visibility of the scroll bar.
+	scrollBarVisibility ScrollBarVisibility
 
 	// The scroll bar color.
 	scrollBarColor tcell.Color
@@ -304,11 +304,11 @@ type TreeView struct {
 // NewTreeView returns a new tree view.
 func NewTreeView() *TreeView {
 	return &TreeView{
-		Box:            NewBox(),
-		showScrollBar:  true,
-		graphics:       true,
-		graphicsColor:  Styles.GraphicsColor,
-		scrollBarColor: Styles.ScrollBarColor,
+		Box:                 NewBox(),
+		scrollBarVisibility: ScrollBarAuto,
+		graphics:            true,
+		graphicsColor:       Styles.GraphicsColor,
+		scrollBarColor:      Styles.ScrollBarColor,
 	}
 }
 
@@ -386,10 +386,9 @@ func (t *TreeView) SetGraphicsColor(color tcell.Color) *TreeView {
 	return t
 }
 
-// ShowScrollBar determines whether or not to render a scroll bar when there
-// are additional nodes offscreen.
-func (t *TreeView) ShowScrollBar(show bool) *TreeView {
-	t.showScrollBar = show
+// SetScrollBarVisibility specifies the display of the scroll bar.
+func (t *TreeView) SetScrollBarVisibility(visibility ScrollBarVisibility) *TreeView {
+	t.scrollBarVisibility = visibility
 	return t
 }
 
@@ -710,7 +709,7 @@ func (t *TreeView) Draw(screen tcell.Screen) {
 		}
 
 		// Draw scroll bar.
-		if t.showScrollBar {
+		if t.scrollBarVisibility == ScrollBarAlways || (t.scrollBarVisibility == ScrollBarAuto && rows > height) {
 			RenderScrollBar(screen, x+(width-1), posY, height, rows, cursor, posY-y, t.hasFocus, tcell.ColorWhite)
 		}
 

util.go

@@ -631,6 +631,20 @@ func iterateStringReverse(text string, callback func(main rune, comb []rune, tex
 	return false
 }
 
+// ScrollBarVisibility specifies the display of a scroll bar.
+type ScrollBarVisibility int
+
+const (
+	// ScrollBarNever never shows a scroll bar.
+	ScrollBarNever ScrollBarVisibility = iota
+
+	// ScrollBarAuto shows a scroll bar when there are items offscreen.
+	ScrollBarAuto
+
+	// ScrollBarAlways always shows a scroll bar.
+	ScrollBarAlways
+)
+
 // RenderScrollBar renders a scroll bar character at the specified position.
 func RenderScrollBar(screen tcell.Screen, x int, y int, height int, items int, cursor int, printed int, focused bool, color tcell.Color) {
 	// Do not render a scroll bar when all items are visible.