Add word selection on double-tap (#96)

Implement word selection functionality triggered by a double-tap.
Words are identified as sequences of alphanumeric characters, while
spaces and punctuation are ignored. Update the selection logic to
highlight the word under the cursor and clear any existing selection.
Adjust tests to validate word selection and ensure accurate behavior
when tapping on non-alphanumeric characters.

position.go

@@ -20,3 +20,11 @@ func (t *Terminal) getTermPosition(pos fyne.Position) position {
 	row := int(pos.Y/cell.Height) + 1
 	return position{col, row}
 }
+
+// getTextPosition converts a terminal position (row and col) to fyne coordinates.
+func (t *Terminal) getTextPosition(pos position) fyne.Position {
+	cell := t.guessCellSize()
+	x := (pos.Col - 1) * int(cell.Width)  // Convert column to pixel position (1-based to 0-based)
+	y := (pos.Row - 1) * int(cell.Height) // Convert row to pixel position (1-based to 0-based)
+	return fyne.NewPos(float32(x), float32(y))
+}

select.go

@@ -52,6 +52,8 @@ func (t *Terminal) clearSelectedText() {
 	t.Refresh()
 	t.blockMode = false
 	t.selecting = false
+	t.selStart = nil
+	t.selEnd = nil
 }
 
 // SelectedText gets the text that is currently selected.

select_test.go

@@ -3,8 +3,10 @@ package terminal
 import (
 	"testing"
 
+	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/widget"
 	widget2 "github.com/fyne-io/terminal/internal/widget"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestGetSelectedRange(t *testing.T) {
@@ -75,7 +77,6 @@ func TestGetSelectedRange(t *testing.T) {
 }
 
 func TestGetTextRange(t *testing.T) {
-	// Prepare the text grid for the tests
 	grid := widget2.NewTermGrid()
 	grid.Rows = []widget.TextGridRow{
 		{Cells: []widget.TextGridCell{{Rune: 'A'}, {Rune: 'B'}, {Rune: 'C'}}},
@@ -109,3 +110,70 @@ func TestGetTextRange(t *testing.T) {
 		})
 	}
 }
+
+func TestDoubleTapped(t *testing.T) {
+	grid := widget2.NewTermGrid()
+	grid.Rows = []widget.TextGridRow{
+		{Cells: []widget.TextGridCell{
+			{Rune: 'H'}, {Rune: 'e'}, {Rune: 'l'}, {Rune: 'l'}, {Rune: 'o'},
+			{Rune: ' '}, {Rune: 'W'}, {Rune: 'o'}, {Rune: 'r'}, {Rune: 'l'},
+			{Rune: 'd'}, {Rune: '!'},
+		}},
+		{Cells: []widget.TextGridCell{
+			{Rune: 'T'}, {Rune: 'e'}, {Rune: 's'}, {Rune: 't'}, {Rune: 'i'},
+			{Rune: 'n'}, {Rune: 'g'}, {Rune: ' '}, {Rune: '1'}, {Rune: '2'},
+			{Rune: '3'}, {Rune: '.'},
+		}},
+	}
+
+	term := &Terminal{
+		content: grid,
+	}
+	term.Resize(fyne.NewSize(500, 500))
+
+	tests := map[string]struct {
+		clickPosition fyne.Position
+		expectedWord  string
+	}{
+		"Double tap on 'Hello'": {
+			clickPosition: term.getTextPosition(position{Row: 1, Col: 1}),
+			expectedWord:  "Hello",
+		},
+		"Double tap on 'World'": {
+			clickPosition: term.getTextPosition(position{Row: 1, Col: 7}),
+			expectedWord:  "World",
+		},
+		"Double tap on '123'": {
+			clickPosition: term.getTextPosition(position{Row: 2, Col: 9}),
+			expectedWord:  "123",
+		},
+		"Double tap on '!' should not select": {
+			clickPosition: term.getTextPosition(position{Row: 1, Col: 12}),
+			expectedWord:  "",
+		},
+		"Double tap on '.' should not select": {
+			clickPosition: term.getTextPosition(position{Row: 2, Col: 12}),
+			expectedWord:  "",
+		},
+		"Double tap on space between words": {
+			clickPosition: term.getTextPosition(position{Row: 1, Col: 6}),
+			expectedWord:  "",
+		},
+	}
+
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			term.clearSelectedText()
+			term.DoubleTapped(&fyne.PointEvent{
+				Position: tc.clickPosition,
+			})
+
+			selectedWord := ""
+			if term.hasSelectedText() {
+				selectedWord = term.SelectedText()
+			}
+
+			assert.Equal(t, tc.expectedWord, selectedWord)
+		})
+	}
+}

term.go

@@ -9,6 +9,7 @@ import (
 	"runtime"
 	"sync"
 	"time"
+	"unicode"
 
 	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/canvas"
@@ -158,6 +159,51 @@ func (t *Terminal) MouseUp(ev *desktop.MouseEvent) {
 	}
 }
 
+// DoubleTapped handles the double tapped event.
+func (t *Terminal) DoubleTapped(pe *fyne.PointEvent) {
+	pos := t.sanitizePosition(pe.Position)
+	termPos := t.getTermPosition(*pos)
+	row, col := termPos.Row, termPos.Col
+
+	if t.hasSelectedText() {
+		t.clearSelectedText()
+	}
+
+	if row < 1 || row > len(t.content.Rows) {
+		return
+	}
+
+	rowContent := t.content.Rows[row-1].Cells
+
+	if col < 0 || col >= len(rowContent) {
+		return // No valid character under the cursor, do nothing
+	}
+
+	start, end := col-1, col-1
+
+	if !unicode.IsLetter(rowContent[start].Rune) && !unicode.IsDigit(rowContent[start].Rune) {
+		return
+	}
+
+	for start > 0 && (unicode.IsLetter(rowContent[start-1].Rune) || unicode.IsDigit(rowContent[start-1].Rune)) {
+		start--
+	}
+	if start < len(rowContent) && !unicode.IsLetter(rowContent[start].Rune) && !unicode.IsDigit(rowContent[start].Rune) {
+		start++
+	}
+	for end < len(rowContent) && (unicode.IsLetter(rowContent[end].Rune) || unicode.IsDigit(rowContent[end].Rune)) {
+		end++
+	}
+	if start == end {
+		return
+	}
+
+	t.selStart = &position{Row: row, Col: start + 1}
+	t.selEnd = &position{Row: row, Col: end}
+
+	t.highlightSelectedText()
+}
+
 // RemoveListener de-registers a Config channel and closes it
 func (t *Terminal) RemoveListener(listener chan Config) {
 	t.listenerLock.Lock()