Add support for double click / drag selection

canvasobject.go

@@ -35,6 +35,11 @@ type Tappable interface {
 	TappedSecondary(*PointEvent)
 }
 
+// DoubleTappable describes any CanvasObject that can also be double tapped.
+type DoubleTappable interface {
+	DoubleTapped(*PointEvent)
+}
+
 // Disableable describes any CanvasObject that can be disabled.
 // This is primarily used with objects that also implement the Tappable interface.
 type Disableable interface {

internal/driver/gl/window.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"runtime"
 	"strconv"
+	"sync"
 	"time"
 
 	"fyne.io/fyne"
@@ -19,7 +20,8 @@ import (
 )
 
 const (
-	scrollSpeed = 10
+	scrollSpeed      = 10
+	doubleClickDelay = 500 // ms (minimum interval between clicks for double click detection)
 )
 
 var (
@@ -52,11 +54,12 @@ type window struct {
 	padded     bool
 	visible    bool
 
-	mousePos     fyne.Position
-	mouseDragPos fyne.Position
-	mouseButton  desktop.MouseButton
-	mouseOver    desktop.Hoverable
-	onClosed     func()
+	mousePos       fyne.Position
+	mouseDragPos   fyne.Position
+	mouseButton    desktop.MouseButton
+	mouseOver      desktop.Hoverable
+	mouseClickTime time.Time
+	onClosed       func()
 
 	xpos, ypos    int
 	width, height int
@@ -628,14 +631,25 @@ func (w *window) mouseClicked(viewport *glfw.Window, button glfw.MouseButton, ac
 	ev := new(fyne.PointEvent)
 	ev.Position = fyne.NewPos(x, y)
 
+	// Prevent async mouse functions from arriving out of order
+	var mouseWG sync.WaitGroup
+
 	if wid, ok := co.(desktop.Mouseable); ok {
 		mev := new(desktop.MouseEvent)
 		mev.Position = ev.Position
 		mev.Button = convertMouseButton(button)
 		if action == glfw.Press {
-			go wid.MouseDown(mev)
+			mouseWG.Add(1)
+			go func() {
+				defer mouseWG.Done()
+				wid.MouseDown(mev)
+			}()
 		} else if action == glfw.Release {
-			go wid.MouseUp(mev)
+			mouseWG.Add(1)
+			go func() {
+				defer mouseWG.Done()
+				wid.MouseUp(mev)
+			}()
 		}
 	}
 
@@ -661,8 +675,27 @@ func (w *window) mouseClicked(viewport *glfw.Window, button glfw.MouseButton, ac
 			w.canvas.Focus(wid)
 		}
 	}
+
+	// Check for double click on mouse left release
+	if action == glfw.Release && button == glfw.MouseButtonLeft {
+		now := time.Now()
+		// we can safely subtract the first "zero" time as it'll be much larger than doubleClickDelay
+		if now.Sub(w.mouseClickTime).Nanoseconds()/1e6 <= doubleClickDelay {
+			if wid, ok := co.(fyne.DoubleTappable); ok {
+				mouseWG.Wait() // wait for any mouse events to finish
+				mouseWG.Add(1)
+				go func() {
+					defer mouseWG.Done()
+					wid.DoubleTapped(ev)
+				}()
+			}
+		}
+		w.mouseClickTime = now
+	}
+
 	if wid, ok := co.(fyne.Tappable); ok {
 		if action == glfw.Release {
+			mouseWG.Wait() // wait for any mouse events to finish
 			switch button {
 			case glfw.MouseButtonRight:
 				go wid.TappedSecondary(ev)

widget/entry.go

@@ -426,25 +426,41 @@ func (e *Entry) Focused() bool {
 func (e *Entry) cursorColAt(text []rune, pos fyne.Position) int {
 	for i := 0; i < len(text); i++ {
 		str := string(text[0 : i+1])
-		wid := textMinSize(str, theme.TextSize(), e.textStyle()).Width
+		wid := textMinSize(str, theme.TextSize(), e.textStyle()).Width + theme.Padding()
 		if wid > pos.X {
 			return i
 		}
 	}
 	return len(text)
 }
 
-// Tapped is called when this entry has been tapped so we should update the cursor position.
-func (e *Entry) Tapped(ev *fyne.PointEvent) {
-	if !e.focused {
-		e.FocusGained()
-	}
+// MouseDown called on mouse click, this triggers a mouse click which can move the cursor,
+// update the existing selection (if shift is held), or start a selection dragging operation.
+func (e *Entry) MouseDown(m *desktop.MouseEvent) {
 	if e.selectKeyDown {
 		e.selecting = true
 	}
 	if e.selecting && e.selectKeyDown == false {
 		e.selecting = false
 	}
+	e.updateMousePointer(&m.PointEvent, e.selecting == false)
+}
+
+// MouseUp called on mouse release (ignored)
+func (e *Entry) MouseUp(m *desktop.MouseEvent) {
+}
+
+// Dragged is called when the pointer moves while a button is held down
+func (e *Entry) Dragged(d *fyne.DragEvent) {
+	e.selecting = true
+	e.updateMousePointer(&d.PointEvent, false)
+}
+
+func (e *Entry) updateMousePointer(ev *fyne.PointEvent, startSelect bool) {
+
+	if !e.focused {
+		e.FocusGained()
+	}
 
 	rowHeight := e.textProvider().charMinSize().Height
 	row := int(math.Floor(float64(ev.Position.Y-theme.Padding()) / float64(rowHeight)))
@@ -461,12 +477,66 @@ func (e *Entry) Tapped(ev *fyne.PointEvent) {
 	e.Lock()
 	e.CursorRow = row
 	e.CursorColumn = col
+	if startSelect {
+		e.selectRow = row
+		e.selectColumn = col
+	}
 	e.Unlock()
 	Renderer(e).(*entryRenderer).moveCursor()
 }
 
-// TappedSecondary is called when right or alternative tap is invoked - this is currently ignored.
-func (e *Entry) TappedSecondary(_ *fyne.PointEvent) {
+// DoubleTapped is called when this entry has been double tapped so we should select text below the pointer
+func (e *Entry) DoubleTapped(ev *fyne.PointEvent) {
+	row := e.textProvider().row(e.CursorRow)
+	start, end := e.CursorColumn, e.CursorColumn+1
+	if start >= len(row) {
+		start = len(row) - 1
+	}
+	if end >= len(row) {
+		end = len(row) - 1
+	}
+
+	if row[start] == ' ' || row[start] == '\t' {
+		// whitespace clicked, select all whitespace (search in both directions for non-whitespace)
+		for ; start > 0; start-- {
+			if row[start-1] != ' ' && row[start-1] != '\t' {
+				break
+			}
+		}
+		for ; end < len(row); end++ {
+			// find first non-whitespace rune
+			if row[end] != ' ' && row[end] != '\t' {
+				break
+			}
+		}
+	} else {
+		// text clicked, select all text (search in both directions for whitespace)
+		for ; start > 0; start-- {
+			if row[start-1] == ' ' || row[start-1] == '\t' {
+				break
+			}
+		}
+		for ; end < len(row); end++ {
+			if row[end] == ' ' || row[end] == '\t' || row[end] == '\r' || row[end] == '\n' {
+				break
+			}
+		}
+	}
+
+	e.Lock()
+	if e.selectKeyDown == false {
+		e.selectRow = e.CursorRow
+		e.selectColumn = start
+	}
+	// Always aim to maximise the selected region
+	if e.selectRow > e.CursorRow || (e.selectRow == e.CursorRow && e.selectColumn > e.CursorColumn) {
+		e.CursorColumn = start
+	} else {
+		e.CursorColumn = end
+	}
+	e.selecting = true
+	e.Unlock()
+	Renderer(e).(*entryRenderer).moveCursor()
 }
 
 // TypedRune receives text input events when the Entry widget is focused.