Add ContextMenu

CHANGELOG

@@ -1,5 +1,6 @@
 v1.4.5 (WIP)
 - Add multithreading support
+- Add ContextMenu (initially supported by List)
 - Merge upstream mouse support
 
 v1.4.4 (2020-02-24)

README.md

@@ -22,7 +22,7 @@ Available widgets:
 - Navigable multi-color __text views__
 - Sophisticated navigable __table views__
 - Flexible __tree views__
-- Selectable __lists__
+- Selectable __lists__ with __context menus__
 - __Grid__, __Flexbox__ and __page layouts__
 - Modal __message windows__
 - Horizontal and vertical __progress bars__

box.go

@@ -50,6 +50,9 @@ type Box struct {
 	// Whether or not this box has focus.
 	hasFocus bool
 
+	// Whether or not this box shows its focus.
+	showFocus bool
+
 	// An optional capture function which receives a key event and returns the
 	// event to be forwarded to the primitive's default input handler (nil if
 	// nothing should be forwarded).
@@ -76,6 +79,7 @@ func NewBox() *Box {
 		borderColor:     Styles.BorderColor,
 		titleColor:      Styles.TitleColor,
 		titleAlign:      AlignCenter,
+		showFocus:       true,
 	}
 	b.focus = b
 	return b
@@ -389,7 +393,7 @@ func (b *Box) Draw(screen tcell.Screen) {
 		} else {
 			hasFocus = b.focus.HasFocus()
 		}
-		if hasFocus {
+		if hasFocus && b.showFocus {
 			horizontal = Borders.HorizontalFocus
 			vertical = Borders.VerticalFocus
 			topLeft = Borders.TopLeftFocus

contextmenu.go

@@ -0,0 +1,151 @@
+package cview
+
+import "sync"
+
+// ContextMenu is a menu that appears upon user interaction, such as right
+// clicking or pressing Alt+Enter.
+type ContextMenu struct {
+	parent   Primitive
+	item     int
+	open     bool
+	drag     bool
+	list     *List
+	x, y     int
+	selected func(int, string, rune)
+
+	l sync.Mutex
+}
+
+// NewContextMenu returns a new context menu.
+func NewContextMenu(parent Primitive) *ContextMenu {
+	c := &ContextMenu{parent: parent}
+
+	return c
+}
+
+// ContextMenuList returns the underlying List of the context menu.
+func (c *ContextMenu) ContextMenuList() *List {
+	c.l.Lock()
+	defer c.l.Unlock()
+
+	return c.list
+}
+
+// AddContextItem adds an item to the context menu. Adding an item with no text
+// or shortcut will add a divider.
+func (c *ContextMenu) AddContextItem(text string, shortcut rune, selected func(index int)) *ContextMenu {
+	c.l.Lock()
+	defer c.l.Unlock()
+
+	if c.list == nil {
+		c.list = NewList().
+			ShowSecondaryText(false).
+			SetHover(true).
+			SetWrapAround(true)
+		c.list.
+			SetBorder(true).
+			SetBorderPadding(
+				Styles.ContextMenuPaddingTop,
+				Styles.ContextMenuPaddingBottom,
+				Styles.ContextMenuPaddingLeft,
+				Styles.ContextMenuPaddingRight)
+		c.list.showFocus = false
+	}
+
+	c.list.AddItem(text, "", shortcut, c.wrap(selected))
+	if text == "" && shortcut == 0 {
+		c.list.Lock()
+		index := len(c.list.items) - 1
+		c.list.items[index].Enabled = false
+		c.list.Unlock()
+	}
+
+	return c
+}
+
+func (c *ContextMenu) wrap(f func(index int)) func() {
+	return func() {
+		f(c.item)
+	}
+}
+
+// ClearContextMenu removes all items from the context menu.
+func (c *ContextMenu) ClearContextMenu() *ContextMenu {
+	c.l.Lock()
+	defer c.l.Unlock()
+
+	if c.list != nil {
+		c.list.Clear()
+	}
+
+	return c
+}
+
+// SetContextSelectedFunc sets the function which is called when the user
+// selects a context menu item. The function receives the item's index in the
+// menu (starting with 0), its text and its shortcut rune. SetSelectedFunc must
+// be called before the context menu is shown.
+func (c *ContextMenu) SetContextSelectedFunc(handler func(index int, text string, shortcut rune)) *ContextMenu {
+	c.l.Lock()
+	defer c.l.Unlock()
+
+	c.selected = handler
+	return c
+}
+
+// ShowContextMenu shows the context menu.
+func (c *ContextMenu) ShowContextMenu(item int, x int, y int, setFocus func(Primitive)) {
+	c.l.Lock()
+	defer c.l.Unlock()
+
+	c.show(item, x, y, setFocus)
+}
+
+func (c *ContextMenu) show(item int, x int, y int, setFocus func(Primitive)) {
+	if c.list == nil || len(c.list.items) == 0 {
+		return
+	}
+
+	c.open = true
+	c.item = item
+	c.x, c.y = x, y
+
+	c.list.Lock()
+	for i, item := range c.list.items {
+		if item.Enabled {
+			c.list.currentItem = i
+			break
+		}
+	}
+	c.list.Unlock()
+
+	c.list.SetSelectedFunc(func(index int, mainText, secondaryText string, shortcut rune) {
+		c.l.Lock()
+
+		// A context item was selected. Close the menu.
+		c.hide(setFocus)
+
+		if c.selected != nil {
+			c.l.Unlock()
+			c.selected(index, mainText, shortcut)
+		} else {
+			c.l.Unlock()
+		}
+	}).SetDoneFunc(func() {
+		c.hide(setFocus)
+	})
+
+	setFocus(c.list)
+}
+
+func (c *ContextMenu) hide(setFocus func(Primitive)) {
+	c.open = false
+
+	if c.list == nil {
+		return
+	}
+
+	if c.list.HasFocus() {
+		setFocus(c.parent)
+	}
+}

demos/list/main.go

@@ -7,14 +7,51 @@ import (
 
 func main() {
 	app := cview.NewApplication()
-	list := cview.NewList().
-		AddItem("List item 1", "Some explanatory text", 'a', nil).
-		AddItem("List item 2", "Some explanatory text", 'b', nil).
-		AddItem("List item 3", "Some explanatory text", 'c', nil).
-		AddItem("List item 4", "Some explanatory text", 'd', nil).
-		AddItem("Quit", "Press to exit", 'q', func() {
-			app.Stop()
-		})
+	list := cview.NewList()
+
+	reset := func() {
+		list.
+			Clear().
+			AddItem("List item 1", "Some explanatory text", 'a', nil).
+			AddItem("List item 2", "Some explanatory text", 'b', nil).
+			AddItem("List item 3", "Some explanatory text", 'c', nil).
+			AddItem("List item 4", "Some explanatory text", 'd', nil).
+			AddItem("Quit", "Press to exit", 'q', func() {
+				app.Stop()
+			})
+
+		list.ContextMenuList().SetItemEnabled(3, false)
+	}
+
+	list.AddContextItem("Delete item", 'i', func(index int) {
+		list.RemoveItem(index)
+
+		if list.GetItemCount() == 0 {
+			list.ContextMenuList().SetItemEnabled(0, false)
+			list.ContextMenuList().SetItemEnabled(1, false)
+		}
+		list.ContextMenuList().SetItemEnabled(3, true)
+	})
+
+	list.AddContextItem("Delete all", 'a', func(index int) {
+		list.Clear()
+
+		list.ContextMenuList().SetItemEnabled(0, false)
+		list.ContextMenuList().SetItemEnabled(1, false)
+		list.ContextMenuList().SetItemEnabled(3, true)
+	})
+
+	list.AddContextItem("", 0, nil)
+
+	list.AddContextItem("Reset", 'r', func(index int) {
+		reset()
+
+		list.ContextMenuList().SetItemEnabled(0, true)
+		list.ContextMenuList().SetItemEnabled(1, true)
+		list.ContextMenuList().SetItemEnabled(3, false)
+	})
+
+	reset()
 	if err := app.SetRoot(list, true).EnableMouse(true).Run(); err != nil {
 		panic(err)
 	}

demos/presentation/introduction.go

@@ -4,11 +4,49 @@ import "gitlab.com/tslocum/cview"
 
 // Introduction returns a cview.List with the highlights of the cview package.
 func Introduction(nextSlide func()) (title string, content cview.Primitive) {
-	list := cview.NewList().
-		AddItem("A Go package for terminal based UIs", "with a special focus on rich interactive widgets", '1', nextSlide).
-		AddItem("Based on github.com/gdamore/tcell", "Like termbox but better (see tcell docs)", '2', nextSlide).
-		AddItem("Designed to be simple", `"Hello world" is 5 lines of code`, '3', nextSlide).
-		AddItem("Good for data entry", `For charts, use "termui" - for low-level views, use "gocui" - ...`, '4', nextSlide).
-		AddItem("Extensive documentation", "Demo code is available for each widget", '5', nextSlide)
-	return "Introduction", Center(80, 10, list)
+	list := cview.NewList()
+
+	reset := func() {
+		list.
+			Clear().
+			AddItem("A Go package for terminal based UIs", "with a special focus on rich interactive widgets", '1', nextSlide).
+			AddItem("Based on github.com/gdamore/tcell", "Like termbox but better (see tcell docs)", '2', nextSlide).
+			AddItem("Designed to be simple", `"Hello world" is 5 lines of code`, '3', nextSlide).
+			AddItem("Good for data entry", `For charts, use "termui" - for low-level views, use "gocui" - ...`, '4', nextSlide).
+			AddItem("Supports context menus", "Right click on one of these items or press Alt+Enter", '5', nextSlide).
+			AddItem("Extensive documentation", "Demo code is available for each widget", '6', nextSlide)
+
+		list.ContextMenuList().SetItemEnabled(3, false)
+	}
+
+	list.AddContextItem("Delete item", 'i', func(index int) {
+		list.RemoveItem(index)
+
+		if list.GetItemCount() == 0 {
+			list.ContextMenuList().SetItemEnabled(0, false)
+			list.ContextMenuList().SetItemEnabled(1, false)
+		}
+		list.ContextMenuList().SetItemEnabled(3, true)
+	})
+
+	list.AddContextItem("Delete all", 'a', func(index int) {
+		list.Clear()
+
+		list.ContextMenuList().SetItemEnabled(0, false)
+		list.ContextMenuList().SetItemEnabled(1, false)
+		list.ContextMenuList().SetItemEnabled(3, true)
+	})
+
+	list.AddContextItem("", 0, nil)
+
+	list.AddContextItem("Reset", 'r', func(index int) {
+		reset()
+
+		list.ContextMenuList().SetItemEnabled(0, true)
+		list.ContextMenuList().SetItemEnabled(1, true)
+		list.ContextMenuList().SetItemEnabled(3, false)
+	})
+
+	reset()
+	return "Introduction", Center(80, 12, list)
 }

go.mod

@@ -7,6 +7,6 @@ require (
 	github.com/lucasb-eyer/go-colorful v1.0.3
 	github.com/mattn/go-runewidth v0.0.9
 	github.com/rivo/uniseg v0.1.0
-	golang.org/x/sys v0.0.0-20200327173247-9dae0f8f5775 // indirect
+	golang.org/x/sys v0.0.0-20200413165638-669c56c373c4 // indirect
 	golang.org/x/text v0.3.2 // indirect
 )

go.sum

@@ -16,8 +16,8 @@ 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 v0.0.0-20200327173247-9dae0f8f5775 h1:TC0v2RSO1u2kn1ZugjrFXkRZAEaqMN/RW+OTZkBzmLE=
-golang.org/x/sys v0.0.0-20200327173247-9dae0f8f5775/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200413165638-669c56c373c4 h1:opSr2sbRXk5X5/givKrrKj9HXxFpW2sdCiP8MJSKLQY=
+golang.org/x/sys v0.0.0-20200413165638-669c56c373c4/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=

list.go

@@ -10,6 +10,7 @@ import (
 
 // listItem represents one item in a List.
 type listItem struct {
+	Enabled       bool   // Whether or not the list item is selectable.
 	MainText      string // The main text of the list item.
 	SecondaryText string // A secondary text to be shown underneath the main text.
 	Shortcut      rune   // The key to select the list item directly, 0 if there is no shortcut.
@@ -21,6 +22,7 @@ type listItem struct {
 // See https://gitlab.com/tslocum/cview/wiki/List for an example.
 type List struct {
 	*Box
+	*ContextMenu
 
 	// The items of the list.
 	items []*listItem
@@ -61,6 +63,9 @@ type List struct {
 	// Whether or not navigating the list will wrap around.
 	wrapAround bool
 
+	// Whether or not hovering over an item will highlight it.
+	hover bool
+
 	// The number of list items skipped at the top before the first item is drawn.
 	offset int
 
@@ -80,7 +85,7 @@ type List struct {
 
 // NewList returns a new form.
 func NewList() *List {
-	return &List{
+	l := &List{
 		Box:                     NewBox(),
 		showSecondaryText:       true,
 		scrollBarVisibility:     ScrollBarAuto,
@@ -91,6 +96,11 @@ func NewList() *List {
 		scrollBarColor:          Styles.ScrollBarColor,
 		selectedBackgroundColor: Styles.PrimaryTextColor,
 	}
+
+	l.ContextMenu = NewContextMenu(l)
+	l.focus = l
+
+	return l
 }
 
 // SetCurrentItem sets the currently selected item by its index, starting at 0
@@ -172,7 +182,7 @@ func (l *List) RemoveItem(index int) *List {
 
 	// Shift current item.
 	previousCurrentItem := l.currentItem
-	if l.currentItem >= index {
+	if l.currentItem >= index && l.currentItem > 0 {
 		l.currentItem--
 	}
 
@@ -283,6 +293,16 @@ func (l *List) SetScrollBarColor(color tcell.Color) *List {
 	return l
 }
 
+// SetHover sets the flag that determines whether hovering over an item will
+// highlight it (without triggering callbacks set with SetSelectedFunc).
+func (l *List) SetHover(hover bool) *List {
+	l.Lock()
+	defer l.Unlock()
+
+	l.hover = hover
+	return l
+}
+
 // SetWrapAround sets the flag that determines whether navigating the list will
 // wrap around. That is, navigating downwards on the last item will move the
 // selection to the first item (similarly in the other direction). If set to
@@ -364,6 +384,7 @@ func (l *List) InsertItem(index int, mainText, secondaryText string, shortcut ru
 	l.Lock()
 
 	item := &listItem{
+		Enabled:       true,
 		MainText:      mainText,
 		SecondaryText: secondaryText,
 		Shortcut:      shortcut,
@@ -433,6 +454,17 @@ func (l *List) SetItemText(index int, main, secondary string) *List {
 	return l
 }
 
+// SetItemEnabled sets whether an item is selectable. Panics if the index is
+// out of range.
+func (l *List) SetItemEnabled(index int, enabled bool) *List {
+	l.Lock()
+	defer l.Unlock()
+
+	item := l.items[index]
+	item.Enabled = enabled
+	return l
+}
+
 // FindItems searches the main and secondary texts for the given strings and
 // returns a list of item indices in which those strings are found. One of the
 // two search strings may be empty, it will then be ignored. Indices are always
@@ -486,9 +518,29 @@ func (l *List) Clear() *List {
 	return l
 }
 
+// Focus is called by the application when the primitive receives focus.
+func (l *List) Focus(delegate func(p Primitive)) {
+	l.Box.Focus(delegate)
+	if l.ContextMenu.open {
+		delegate(l.ContextMenu.list)
+	}
+}
+
+// HasFocus returns whether or not this primitive has focus.
+func (l *List) HasFocus() bool {
+	l.RLock()
+	defer l.RUnlock()
+
+	if l.ContextMenu.open {
+		return l.ContextMenu.list.HasFocus()
+	}
+	return l.hasFocus
+}
+
 // Draw draws this primitive onto the screen.
 func (l *List) Draw(screen tcell.Screen) {
 	l.Box.Draw(screen)
+	hasFocus := l.GetFocusable().HasFocus()
 
 	l.Lock()
 	defer l.Unlock()
@@ -499,7 +551,7 @@ func (l *List) Draw(screen tcell.Screen) {
 
 	screenWidth, _ := screen.Size()
 	scrollBarHeight := height
-	scrollBarX := x + (width - 1)
+	scrollBarX := x + (width - 1) + l.paddingLeft + l.paddingRight
 	if scrollBarX > screenWidth-1 {
 		scrollBarX = screenWidth - 1
 	}
@@ -543,6 +595,28 @@ func (l *List) Draw(screen tcell.Screen) {
 			break
 		}
 
+		if item.MainText == "" && item.SecondaryText == "" && item.Shortcut == 0 { // Divider
+			Print(screen, string(tcell.RuneLTee), (x-5)-l.paddingLeft, y, 1, AlignLeft, l.mainTextColor)
+			Print(screen, strings.Repeat(string(tcell.RuneHLine), width+4+l.paddingLeft+l.paddingRight), (x-4)-l.paddingLeft, y, width+4+l.paddingLeft+l.paddingRight, AlignLeft, l.mainTextColor)
+			Print(screen, string(tcell.RuneRTee), (x-5)+width+5+l.paddingRight, y, 1, AlignLeft, l.mainTextColor)
+
+			RenderScrollBar(screen, l.scrollBarVisibility, scrollBarX, y, scrollBarHeight, len(l.items), l.currentItem, index-l.offset, l.hasFocus, l.scrollBarColor)
+			y++
+			continue
+		} else if !item.Enabled { // Disabled item
+			// Shortcuts.
+			if showShortcuts && item.Shortcut != 0 {
+				Print(screen, fmt.Sprintf("(%s)", string(item.Shortcut)), x-5, y, 4, AlignRight, tcell.ColorDarkSlateGray)
+			}
+
+			// Main text.
+			Print(screen, item.MainText, x, y, width, AlignLeft, tcell.ColorGray)
+
+			RenderScrollBar(screen, l.scrollBarVisibility, scrollBarX, y, scrollBarHeight, len(l.items), l.currentItem, index-l.offset, l.hasFocus, l.scrollBarColor)
+			y++
+			continue
+		}
+
 		// Shortcuts.
 		if showShortcuts && item.Shortcut != 0 {
 			Print(screen, fmt.Sprintf("(%s)", string(item.Shortcut)), x-5, y, 4, AlignRight, l.shortcutColor)
@@ -595,6 +669,59 @@ func (l *List) Draw(screen tcell.Screen) {
 
 		y++
 	}
+
+	// Draw context menu.
+	if hasFocus && l.ContextMenu.open {
+		list := l.ContextMenu.list
+
+		x, y, width, height = l.GetInnerRect()
+
+		// What's the longest option text?
+		maxWidth := 0
+		for _, option := range list.items {
+			strWidth := TaggedStringWidth(option.MainText)
+			if option.Shortcut != 0 {
+				strWidth += 4
+			}
+			if strWidth > maxWidth {
+				maxWidth = strWidth
+			}
+		}
+
+		lheight := len(list.items)
+		lwidth := maxWidth
+
+		// Add space for borders
+		lwidth += 2
+		lheight += 2
+
+		lwidth += l.list.paddingLeft + l.list.paddingRight
+		lheight += l.list.paddingTop + l.list.paddingBottom
+
+		cx, cy := l.ContextMenu.x, l.ContextMenu.y
+		if cx < 0 || cy < 0 {
+			cx = x + (width / 2)
+			cy = y + (height / 2)
+		}
+
+		_, sheight := screen.Size()
+		if cy+lheight >= sheight && cy-2 > lheight-cy {
+			cy = y - lheight
+			if cy < 0 {
+				cy = 0
+			}
+		}
+		if cy+lheight >= sheight {
+			lheight = sheight - cy
+		}
+
+		if list.scrollBarVisibility == ScrollBarAlways || (list.scrollBarVisibility == ScrollBarAuto && len(list.items) > lheight) {
+			lwidth++ // Add space for scroll bar
+		}
+
+		list.SetRect(cx, cy, lwidth, lheight)
+		list.Draw(screen)
+	}
 }
 
 // InputHandler returns the handler for this primitive.
@@ -603,12 +730,19 @@ func (l *List) InputHandler() func(event *tcell.EventKey, setFocus func(p Primit
 		l.Lock()
 
 		if event.Key() == tcell.KeyEscape {
+			if l.ContextMenu.open {
+				l.ContextMenu.hide(setFocus)
+				return
+			}
+
 			if l.done != nil {
+				l.Unlock()
 				l.done()
+			} else {
+				l.Unlock()
 			}
-			l.Unlock()
 			return
-		} else if len(l.items) == 0 {
+		} else if len(l.items) == 0 && (event.Key() != tcell.KeyEnter || event.Modifiers()&tcell.ModAlt == 0) {
 			l.Unlock()
 			return
 		}
@@ -629,17 +763,40 @@ func (l *List) InputHandler() func(event *tcell.EventKey, setFocus func(p Primit
 		case tcell.KeyPgUp:
 			l.currentItem -= 5
 		case tcell.KeyEnter:
-			if l.currentItem >= 0 && l.currentItem < len(l.items) {
-				item := l.items[l.currentItem]
-				if item.Selected != nil {
-					l.Unlock()
-					item.Selected()
-					l.Lock()
+			if event.Modifiers()&tcell.ModAlt != 0 {
+				// Do we show any shortcuts?
+				var showShortcuts bool
+				for _, item := range l.items {
+					if item.Shortcut != 0 {
+						showShortcuts = true
+						break
+					}
+				}
+
+				offsetX := 7
+				if showShortcuts {
+					offsetX += 4
+				}
+				offsetY := l.currentItem
+				if l.showSecondaryText {
+					offsetY *= 2
 				}
-				if l.selected != nil {
-					l.Unlock()
-					l.selected(l.currentItem, item.MainText, item.SecondaryText, item.Shortcut)
-					l.Lock()
+
+				x, y, _, _ := l.GetInnerRect()
+				l.ContextMenu.show(l.currentItem, x+offsetX, y+offsetY, setFocus)
+			} else if l.currentItem >= 0 && l.currentItem < len(l.items) {
+				item := l.items[l.currentItem]
+				if item.Enabled {
+					if item.Selected != nil {
+						l.Unlock()
+						item.Selected()
+						l.Lock()
+					}
+					if l.selected != nil {
+						l.Unlock()
+						l.selected(l.currentItem, item.MainText, item.SecondaryText, item.Shortcut)
+						l.Lock()
+					}
 				}
 			}
 		case tcell.KeyRune:
@@ -648,7 +805,7 @@ func (l *List) InputHandler() func(event *tcell.EventKey, setFocus func(p Primit
 				// It's not a space bar. Is it a shortcut?
 				var found bool
 				for index, item := range l.items {
-					if item.Shortcut == ch {
+					if item.Enabled && item.Shortcut == ch {
 						// We have a shortcut.
 						found = true
 						l.currentItem = index
@@ -672,17 +829,31 @@ func (l *List) InputHandler() func(event *tcell.EventKey, setFocus func(p Primit
 			}
 		}
 
-		if l.currentItem < 0 {
-			if l.wrapAround {
-				l.currentItem = len(l.items) - 1
-			} else {
-				l.currentItem = 0
+		decreasing := l.currentItem < previousItem
+		for i := 0; i < len(l.items); i++ {
+			if l.currentItem < 0 {
+				if l.wrapAround {
+					l.currentItem = len(l.items) - 1
+				} else {
+					l.currentItem = 0
+				}
+			} else if l.currentItem >= len(l.items) {
+				if l.wrapAround {
+					l.currentItem = 0
+				} else {
+					l.currentItem = len(l.items) - 1
+				}
 			}
-		} else if l.currentItem >= len(l.items) {
-			if l.wrapAround {
-				l.currentItem = 0
+
+			item := l.items[l.currentItem]
+			if item.Enabled {
+				break
+			}
+
+			if decreasing {
+				l.currentItem--
 			} else {
-				l.currentItem = len(l.items) - 1
+				l.currentItem++
 			}
 		}
 
@@ -696,11 +867,31 @@ func (l *List) InputHandler() func(event *tcell.EventKey, setFocus func(p Primit
 	})
 }
 
+// indexAtY returns the index of the list item found at the given Y position
+// or a negative value if there is no such list item.
+func (l *List) indexAtY(y int) int {
+	_, rectY, _, height := l.GetInnerRect()
+	if y < rectY || y >= rectY+height {
+		return -1
+	}
+
+	index := y - rectY
+	if l.showSecondaryText {
+		index /= 2
+	}
+	index += l.offset
+
+	if index >= len(l.items) {
+		return -1
+	}
+	return index
+}
+
 // indexAtPoint returns the index of the list item found at the given position
 // or a negative value if there is no such list item.
 func (l *List) indexAtPoint(x, y int) int {
 	rectX, rectY, width, height := l.GetInnerRect()
-	if rectX < 0 || rectX >= rectX+width || y < rectY || y >= rectY+height {
+	if x < rectX || x >= rectX+width || y < rectY || y >= rectY+height {
 		return -1
 	}
 
@@ -719,6 +910,13 @@ func (l *List) indexAtPoint(x, y int) int {
 // MouseHandler returns the mouse handler for this primitive.
 func (l *List) MouseHandler() func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) {
 	return l.WrapMouseHandler(func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) {
+		// Pass events to context menu.
+		if l.ContextMenu.open && l.ContextMenu.list != nil && l.ContextMenu.list.InRect(event.Position()) {
+			l.ContextMenu.list.MouseHandler()(action, event, setFocus)
+			consumed = true
+			return
+		}
+
 		if !l.InRect(event.Position()) {
 			return false, nil
 		}
@@ -726,22 +924,70 @@ func (l *List) MouseHandler() func(action MouseAction, event *tcell.EventMouse,
 		// Process mouse event.
 		switch action {
 		case MouseLeftClick:
+			if l.ContextMenu.open {
+				l.ContextMenu.hide(setFocus)
+				consumed = true
+				return
+			}
+
 			setFocus(l)
 			index := l.indexAtPoint(event.Position())
 			if index != -1 {
 				item := l.items[index]
-				if item.Selected != nil {
-					item.Selected()
-				}
-				if l.selected != nil {
-					l.selected(index, item.MainText, item.SecondaryText, item.Shortcut)
+				if item.Enabled {
+					if item.Selected != nil {
+						item.Selected()
+					}
+					if l.selected != nil {
+						l.selected(index, item.MainText, item.SecondaryText, item.Shortcut)
+					}
+					if index != l.currentItem && l.changed != nil {
+						l.changed(index, item.MainText, item.SecondaryText, item.Shortcut)
+					}
+					l.currentItem = index
 				}
-				if index != l.currentItem && l.changed != nil {
-					l.changed(index, item.MainText, item.SecondaryText, item.Shortcut)
+			}
+			consumed = true
+		case MouseMiddleClick:
+			if l.ContextMenu.open {
+				l.ContextMenu.hide(setFocus)
+				consumed = true
+				return
+			}
+		case MouseRightDown:
+			x, y := event.Position()
+
+			index := l.indexAtPoint(event.Position())
+			if index != -1 {
+				item := l.items[index]
+				if item.Enabled {
+					if index != l.currentItem && l.changed != nil {
+						l.changed(index, item.MainText, item.SecondaryText, item.Shortcut)
+					}
+					l.currentItem = index
 				}
-				l.currentItem = index
+			}
+
+			if l.ContextMenu.list != nil && len(l.ContextMenu.list.items) > 0 {
+				l.ContextMenu.show(l.currentItem, x, y, setFocus)
+				l.ContextMenu.drag = true
+			} else {
+				defer l.MouseHandler()(MouseLeftClick, event, setFocus)
 			}
 			consumed = true
+		case MouseMove:
+			if l.hover {
+				_, y := event.Position()
+				index := l.indexAtY(y)
+				if index >= 0 {
+					item := l.items[index]
+					if item.Enabled {
+						l.currentItem = index
+					}
+				}
+
+				consumed = true
+			}
 		case MouseScrollUp:
 			if l.offset > 0 {
 				l.offset--

styles.go

@@ -4,34 +4,55 @@ import "github.com/gdamore/tcell"
 
 // Theme defines the colors used when primitives are initialized.
 type Theme struct {
+	// Title, border and other lines
+	TitleColor    tcell.Color // Box titles.
+	BorderColor   tcell.Color // Box borders.
+	GraphicsColor tcell.Color // Graphics.
+
+	// Text
+	PrimaryTextColor           tcell.Color // Primary text.
+	SecondaryTextColor         tcell.Color // Secondary text (e.g. labels).
+	TertiaryTextColor          tcell.Color // Tertiary text (e.g. subtitles, notes).
+	InverseTextColor           tcell.Color // Text on primary-colored backgrounds.
+	ContrastSecondaryTextColor tcell.Color // Secondary text on ContrastBackgroundColor-colored backgrounds.
+
+	// Background
 	PrimitiveBackgroundColor    tcell.Color // Main background color for primitives.
 	ContrastBackgroundColor     tcell.Color // Background color for contrasting elements.
 	MoreContrastBackgroundColor tcell.Color // Background color for even more contrasting elements.
-	BorderColor                 tcell.Color // Box borders.
-	TitleColor                  tcell.Color // Box titles.
-	GraphicsColor               tcell.Color // Graphics.
-	PrimaryTextColor            tcell.Color // Primary text.
-	SecondaryTextColor          tcell.Color // Secondary text (e.g. labels).
-	TertiaryTextColor           tcell.Color // Tertiary text (e.g. subtitles, notes).
-	InverseTextColor            tcell.Color // Text on primary-colored backgrounds.
-	ContrastSecondaryTextColor  tcell.Color // Secondary text on ContrastBackgroundColor-colored backgrounds.
-	ScrollBarColor              tcell.Color // Scroll bar.
+
+	// Context menu
+	ContextMenuPaddingTop    int // Top padding.
+	ContextMenuPaddingBottom int // Bottom padding.
+	ContextMenuPaddingLeft   int // Left padding.
+	ContextMenuPaddingRight  int // Right padding.
+
+	// Scroll bar
+	ScrollBarColor tcell.Color // Scroll bar color.
 }
 
 // Styles defines the theme for applications. The default is for a black
 // background and some basic colors: black, white, yellow, green, cyan, and
 // blue.
 var Styles = Theme{
+	TitleColor:    tcell.ColorWhite,
+	BorderColor:   tcell.ColorWhite,
+	GraphicsColor: tcell.ColorWhite,
+
+	PrimaryTextColor:           tcell.ColorWhite,
+	SecondaryTextColor:         tcell.ColorYellow,
+	TertiaryTextColor:          tcell.ColorGreen,
+	InverseTextColor:           tcell.ColorBlue,
+	ContrastSecondaryTextColor: tcell.ColorDarkCyan,
+
 	PrimitiveBackgroundColor:    tcell.ColorBlack,
 	ContrastBackgroundColor:     tcell.ColorBlue,
 	MoreContrastBackgroundColor: tcell.ColorGreen,
-	BorderColor:                 tcell.ColorWhite,
-	TitleColor:                  tcell.ColorWhite,
-	GraphicsColor:               tcell.ColorWhite,
-	PrimaryTextColor:            tcell.ColorWhite,
-	SecondaryTextColor:          tcell.ColorYellow,
-	TertiaryTextColor:           tcell.ColorGreen,
-	InverseTextColor:            tcell.ColorBlue,
-	ContrastSecondaryTextColor:  tcell.ColorDarkCyan,
-	ScrollBarColor:              tcell.ColorWhite,
+
+	ContextMenuPaddingTop:    0,
+	ContextMenuPaddingBottom: 0,
+	ContextMenuPaddingLeft:   1,
+	ContextMenuPaddingRight:  1,
+
+	ScrollBarColor: tcell.ColorWhite,
 }