2 files changed, 106 insertions(+), 22 deletions(-)

M widget/editor.go
M widget/editor_test.go

@@ 37,6 37,10 @@ type Editor struct {
 	// SingleLine also sets the scrolling direction to
 	// horizontal.
 	SingleLine bool
+	// ReadOnly controls whether the contents of the editor can be altered by
+	// user interaction. If set to true, the editor will allow selecting text
+	// and copying it interactively, but not modifying it.
+	ReadOnly bool
 	// Submit enabled translation of carriage return keys to SubmitEvents.
 	// If not enabled, carriage returns are inserted as newlines in the text.
 	Submit bool


@@ 343,7 347,7 @@ func (e *Editor) processKey(gtx layout.Context) {
 			if !e.focused || ke.State != key.Press {
 				break
 			}
-			if e.Submit && (ke.Name == key.NameReturn || ke.Name == key.NameEnter) {
+			if !e.ReadOnly && e.Submit && (ke.Name == key.NameReturn || ke.Name == key.NameEnter) {
 				if !ke.Modifiers.Contain(key.ModShift) {
 					e.events = append(e.events, SubmitEvent{
 						Text: e.Text(),


@@ 357,6 361,9 @@ func (e *Editor) processKey(gtx layout.Context) {
 		case key.SnippetEvent:
 			e.updateSnippet(gtx, ke.Start, ke.End)
 		case key.EditEvent:
+			if e.ReadOnly {
+				break
+			}
 			e.caret.scroll = true
 			e.scroller.Stop()
 			s := ke.Text


@@ 442,18 449,24 @@ func (e *Editor) command(gtx layout.Context, k key.Event) {
 	}
 	switch k.Name {
 	case key.NameReturn, key.NameEnter:
-		e.append("\n")
+		if !e.ReadOnly {
+			e.append("\n")
+		}
 	case key.NameDeleteBackward:
-		if moveByWord {
-			e.deleteWord(-1)
-		} else {
-			e.Delete(-1)
+		if !e.ReadOnly {
+			if moveByWord {
+				e.deleteWord(-1)
+			} else {
+				e.Delete(-1)
+			}
 		}
 	case key.NameDeleteForward:
-		if moveByWord {
-			e.deleteWord(1)
-		} else {
-			e.Delete(1)
+		if !e.ReadOnly {
+			if moveByWord {
+				e.deleteWord(1)
+			} else {
+				e.Delete(1)
+			}
 		}
 	case key.NameUpArrow:
 		e.moveLines(-1, selAct)


@@ 488,12 501,14 @@ func (e *Editor) command(gtx layout.Context, k key.Event) {
 	// Initiate a paste operation, by requesting the clipboard contents; other
 	// half is in Editor.processKey() under clipboard.Event.
 	case "V":
-		clipboard.ReadOp{Tag: &e.eventKey}.Add(gtx.Ops)
+		if !e.ReadOnly {
+			clipboard.ReadOp{Tag: &e.eventKey}.Add(gtx.Ops)
+		}
 	// Copy or Cut selection -- ignored if nothing selected.
 	case "C", "X":
 		if text := e.SelectedText(); text != "" {
 			clipboard.WriteOp{Text: text}.Add(gtx.Ops)
-			if k.Name == "X" {
+			if k.Name == "X" && !e.ReadOnly {
 				e.Delete(1)
 			}
 		}


@@ 502,10 517,12 @@ func (e *Editor) command(gtx layout.Context, k key.Event) {
 		e.caret.end = 0
 		e.caret.start = e.Len()
 	case "Z":
-		if k.Modifiers.Contain(key.ModShift) {
-			e.redo()
-		} else {
-			e.undo()
+		if !e.ReadOnly {
+			if k.Modifiers.Contain(key.ModShift) {
+				e.redo()
+			} else {
+				e.undo()
+			}
 		}
 	}
 }


@@ 781,7 798,7 @@ func (e *Editor) caretWidth(gtx layout.Context) int {
 }
 
 func (e *Editor) PaintCaret(gtx layout.Context) {
-	if !e.caret.on {
+	if !e.caret.on || e.ReadOnly {
 		return
 	}
 	carWidth2 := e.caretWidth(gtx)

@@ 92,9 92,9 @@ func assertContents(t *testing.T, e *Editor, contents string, selectionStart, se
 	}
 }
 
-// TestEditorZeroDimensions ensures that an empty editor still reserves
-// space for displaying its caret when the constraints allow for it.
-func TestEditorZeroDimensions(t *testing.T) {
+// TestEditorReadOnly ensures that mouse and keyboard interactions with readonly
+// editors do nothing but manipulate the text selection.
+func TestEditorReadOnly(t *testing.T) {
 	gtx := layout.Context{
 		Ops: new(op.Ops),
 		Constraints: layout.Constraints{


@@ 102,13 102,80 @@ func TestEditorZeroDimensions(t *testing.T) {
 		},
 		Locale: english,
 	}
+	gtx.Queue = &testQueue{
+		events: []event.Event{
+			key.FocusEvent{Focus: true},
+		},
+	}
 	cache := text.NewShaper(gofont.Collection())
 	fontSize := unit.Sp(10)
 	font := text.Font{}
 	e := new(Editor)
+	e.ReadOnly = true
+	e.SetText("The quick brown fox jumps over the lazy dog. We just need a few lines of text in the editor so that it can adequately test a few different modes of selection. The quick brown fox jumps over the lazy dog. We just need a few lines of text in the editor so that it can adequately test a few different modes of selection.")
+	cStart, cEnd := e.Selection()
+	if cStart != cEnd {
+		t.Errorf("unexpected initial caret positions")
+	}
 	dims := e.Layout(gtx, cache, font, fontSize, nil)
-	if dims.Size.X < 1 || dims.Size.Y < 1 {
-		t.Errorf("expected empty editor to occupy enough space to display cursor, but returned dimensions %v", dims)
+
+	// Select everything.
+	gtx.Ops.Reset()
+	gtx.Queue.(*testQueue).events = append(gtx.Queue.(*testQueue).events, key.Event{Name: "A", Modifiers: key.ModShortcut})
+	dims = e.Layout(gtx, cache, font, fontSize, nil)
+	textContent := e.Text()
+	cStart2, cEnd2 := e.Selection()
+	if cStart2 > cEnd2 {
+		cStart2, cEnd2 = cEnd2, cStart2
+	}
+	if cEnd2 != e.Len() {
+		t.Errorf("expected selection to contain %d runes, got %d", e.Len(), cEnd2)
+	}
+	if cStart2 != 0 {
+		t.Errorf("expected selection to start at rune 0, got %d", cStart2)
+	}
+
+	// Type some new characters.
+	gtx.Ops.Reset()
+	gtx.Queue.(*testQueue).events = append(gtx.Queue.(*testQueue).events, key.EditEvent{Range: key.Range{Start: cStart2, End: cEnd2}, Text: "something else"})
+	dims = e.Layout(gtx, cache, font, fontSize, nil)
+	textContent2 := e.Text()
+	if textContent2 != textContent {
+		t.Errorf("readonly editor modified by key.EditEvent")
+	}
+
+	// Try to delete selection.
+	gtx.Ops.Reset()
+	gtx.Queue.(*testQueue).events = append(gtx.Queue.(*testQueue).events, key.Event{Name: key.NameDeleteBackward})
+	dims = e.Layout(gtx, cache, font, fontSize, nil)
+	textContent2 = e.Text()
+	if textContent2 != textContent {
+		t.Errorf("readonly editor modified by delete key.Event")
+	}
+
+	// Click and drag from the middle of the first line
+	// to the center.
+	gtx.Ops.Reset()
+	gtx.Queue.(*testQueue).events = append(gtx.Queue.(*testQueue).events,
+		pointer.Event{
+			Type:     pointer.Press,
+			Buttons:  pointer.ButtonPrimary,
+			Position: f32.Pt(float32(dims.Size.X)*.5, 5),
+		},
+		pointer.Event{
+			Type:     pointer.Drag,
+			Buttons:  pointer.ButtonPrimary,
+			Position: layout.FPt(dims.Size).Mul(.5),
+		},
+		pointer.Event{
+			Type:     pointer.Release,
+			Buttons:  pointer.ButtonPrimary,
+			Position: layout.FPt(dims.Size).Mul(.5),
+		},
+	)
+	cStart3, cEnd3 := e.Selection()
+	if cStart3 == cStart2 || cEnd3 == cEnd2 {
+		t.Errorf("expected mouse interaction to change selection.")
 	}
 }