Implemented mouse release handling

_examples/mouse.go

@@ -33,12 +33,24 @@ func main() {
 	}
 }
 
+var initialMouseX, initialMouseY, xOffset, yOffset int
+var globalMouseDown, msgMouseDown, movingMsg bool
+
 func layout(g *gocui.Gui) error {
+	maxX, maxY := g.Size()
+	if _, err := g.View("msg"); msgMouseDown && err == nil {
+		moveMsg(g)
+	}
+	if v, err := g.SetView("global", -1, -1, maxX, maxY, 0); err != nil {
+		if !errors.Is(err, gocui.ErrUnknownView) {
+			return err
+		}
+		v.Frame = false
+	}
 	if v, err := g.SetView("but1", 2, 2, 22, 7, 0); err != nil {
 		if !errors.Is(err, gocui.ErrUnknownView) {
 			return err
 		}
-		v.Highlight = true
 		v.SelBgColor = gocui.ColorGreen
 		v.SelFgColor = gocui.ColorBlack
 		fmt.Fprintln(v, "Button 1 - line 1")
@@ -53,11 +65,11 @@ func layout(g *gocui.Gui) error {
 		if !errors.Is(err, gocui.ErrUnknownView) {
 			return err
 		}
-		v.Highlight = true
 		v.SelBgColor = gocui.ColorGreen
 		v.SelFgColor = gocui.ColorBlack
 		fmt.Fprintln(v, "Button 2 - line 1")
 	}
+	updateHighlightedView(g)
 	return nil
 }
 
@@ -70,13 +82,13 @@ func keybindings(g *gocui.Gui) error {
 			return err
 		}
 	}
-	if err := g.SetKeybinding("msg", gocui.MouseLeft, gocui.ModNone, delMsg); err != nil {
+	if err := g.SetKeybinding("", gocui.MouseRelease, gocui.ModNone, mouseUp); err != nil {
 		return err
 	}
-	if err := g.SetKeybinding("", gocui.MouseRight, gocui.ModNone, delMsg); err != nil {
+	if err := g.SetKeybinding("", gocui.MouseLeft, gocui.ModNone, globalDown); err != nil {
 		return err
 	}
-	if err := g.SetKeybinding("", gocui.MouseMiddle, gocui.ModNone, delMsg); err != nil {
+	if err := g.SetKeybinding("msg", gocui.MouseLeft, gocui.ModNone, msgDown); err != nil {
 		return err
 	}
 	return nil
@@ -100,17 +112,80 @@ func showMsg(g *gocui.Gui, v *gocui.View) error {
 	}
 
 	maxX, maxY := g.Size()
-	if v, err := g.SetView("msg", maxX/2-10, maxY/2, maxX/2+10, maxY/2+2, 0); err != nil {
+	if v, err := g.SetView("msg", maxX/2-10, maxY/2, maxX/2+10, maxY/2+2, 0); err == nil || errors.Is(err, gocui.ErrUnknownView) {
+		v.Clear()
+		v.SelBgColor = gocui.ColorCyan
+		v.SelFgColor = gocui.ColorBlack
+		fmt.Fprintln(v, l)
+	}
+	return nil
+}
+
+func updateHighlightedView(g *gocui.Gui) {
+	mx, my := g.MousePosition()
+	for _, view := range g.Views() {
+		view.Highlight = false
+	}
+	if v, err := g.ViewByPosition(mx, my); err == nil {
+		v.Highlight = true
+	}
+}
+
+func moveMsg(g *gocui.Gui) {
+	mx, my := g.MousePosition()
+	if !movingMsg && (mx != initialMouseX || my != initialMouseY) {
+		movingMsg = true
+	}
+	g.SetView("msg", mx-xOffset, my-yOffset, mx-xOffset+20, my-yOffset+2, 0)
+}
+
+func msgDown(g *gocui.Gui, v *gocui.View) error {
+	initialMouseX, initialMouseY = g.MousePosition()
+	if vx, vy, _, _, err := g.ViewPosition("msg"); err == nil {
+		xOffset = initialMouseX - vx
+		yOffset = initialMouseY - vy
+		msgMouseDown = true
+	}
+	return nil
+}
+
+func globalDown(g *gocui.Gui, v *gocui.View) error {
+	mx, my := g.MousePosition()
+	if vx0, vy0, vx1, vy1, err := g.ViewPosition("msg"); err == nil {
+		if mx >= vx0 && mx <= vx1 && my >= vy0 && my <= vy1 {
+			return msgDown(g, v)
+		}
+	}
+	globalMouseDown = true
+	maxX, _ := g.Size()
+	msg := fmt.Sprintf("Mouse down at: %d,%d", mx, my)
+	x := mx - len(msg)/2
+	if x < 0 {
+		x = 0
+	} else if x+len(msg)+1 > maxX-1 {
+		x = maxX - 1 - len(msg) - 1
+	}
+	if v, err := g.SetView("globalDown", x, my-1, x+len(msg)+1, my+1, 0); err != nil {
 		if !errors.Is(err, gocui.ErrUnknownView) {
 			return err
 		}
-		fmt.Fprintln(v, l)
+		v.WriteString(msg)
 	}
 	return nil
 }
 
-func delMsg(g *gocui.Gui, v *gocui.View) error {
-	// Error check removed, because delete could be called multiple times with the above keybindings
-	g.DeleteView("msg")
+func mouseUp(g *gocui.Gui, v *gocui.View) error {
+	if msgMouseDown {
+		msgMouseDown = false
+		if movingMsg {
+			movingMsg = false
+			return nil
+		} else {
+			g.DeleteView("msg")
+		}
+	} else if globalMouseDown {
+		globalMouseDown = false
+		g.DeleteView("globalDown")
+	}
 	return nil
 }

gui.go

@@ -76,6 +76,9 @@ type Gui struct {
 	testCounter int // used for testing synchronization
 	testNotify  chan struct{}
 
+	// The position of the mouse
+	mouseX, mouseY int
+
 	// BgColor and FgColor allow to configure the background and foreground
 	// colors of the GUI.
 	BgColor, FgColor, FrameColor Attribute
@@ -141,6 +144,7 @@ func NewGui(mode OutputMode, supportOverlaps bool) (*Gui, error) {
 		g.maxX, g.maxY = screen.Size()
 	}
 
+	g.mouseX, g.mouseY = -1, -1
 	g.BgColor, g.FgColor, g.FrameColor = ColorDefault, ColorDefault, ColorDefault
 	g.SelBgColor, g.SelFgColor, g.SelFrameColor = ColorDefault, ColorDefault, ColorDefault
 
@@ -165,6 +169,10 @@ func (g *Gui) Size() (x, y int) {
 	return g.maxX, g.maxY
 }
 
+func (g *Gui) MousePosition() (x, y int) {
+	return g.mouseX, g.mouseY
+}
+
 // SetRune writes a rune at the given point, relative to the top-left
 // corner of the terminal. It checks if the position is valid and applies
 // the given colors.
@@ -881,6 +889,8 @@ func (g *Gui) onKey(ev *gocuiEvent) error {
 		}
 	case eventMouse:
 		mx, my := ev.MouseX, ev.MouseY
+		g.mouseX = mx
+		g.mouseY = my
 		v, err := g.ViewByPosition(mx, my)
 		if err != nil {
 			break

tcell_driver.go

@@ -174,7 +174,7 @@ func pollEvent() gocuiEvent {
 	case *tcell.EventMouse:
 		x, y := tev.Position()
 		button := tev.Buttons()
-		mouseKey := MouseRelease
+		mouseKey := Key(0)
 		mouseMod := ModNone
 		// process mouse wheel
 		if button&tcell.WheelUp != 0 {
@@ -199,19 +199,21 @@ func pollEvent() gocuiEvent {
 		if button != tcell.ButtonNone && lastMouseKey == tcell.ButtonNone {
 			lastMouseKey = button
 			lastMouseMod = tev.Modifiers()
+			switch tev.Buttons() {
+			case tcell.ButtonPrimary:
+				mouseKey = MouseLeft
+			case tcell.ButtonSecondary:
+				mouseKey = MouseRight
+			case tcell.ButtonMiddle:
+				mouseKey = MouseMiddle
+			}
+			mouseMod = Modifier(lastMouseMod)
 		}
 
 		switch tev.Buttons() {
 		case tcell.ButtonNone:
 			if lastMouseKey != tcell.ButtonNone {
-				switch lastMouseKey {
-				case tcell.ButtonPrimary:
-					mouseKey = MouseLeft
-				case tcell.ButtonSecondary:
-					mouseKey = MouseRight
-				case tcell.ButtonMiddle:
-					mouseKey = MouseMiddle
-				}
+				mouseKey = MouseRelease
 				mouseMod = Modifier(lastMouseMod)
 				lastMouseMod = tcell.ModNone
 				lastMouseKey = tcell.ButtonNone