Fix input field horizontal scroll offset not clamping after text deletion

pkg/gocui/gui.go

@@ -327,6 +327,17 @@ func (g *Gui) SetView(name string, x0, y0, x1, y1 int, overlaps byte) (*View, er
 				newViewCursorX, newOriginX := updatedCursorAndOrigin(0, v.InnerWidth(), cursorX)
 				newViewCursorY, newOriginY := updatedCursorAndOrigin(0, v.InnerHeight(), cursorY)
 
+				contentWidth := v.TextArea.GetContentWidth()
+				usableWidth := v.InnerWidth() - 1
+				maxOriginX := contentWidth - usableWidth
+				if maxOriginX < 0 {
+					maxOriginX = 0
+				}
+				if newOriginX > maxOriginX {
+					newOriginX = maxOriginX
+					newViewCursorX = cursorX - newOriginX
+				}
+
 				v.SetCursor(newViewCursorX, newViewCursorY)
 				v.SetOrigin(newOriginX, newOriginY)
 			}

pkg/gocui/text_area.go

@@ -392,6 +392,14 @@ func (self *TextArea) GetUnwrappedContent() string {
 	return self.content
 }
 
+func (self *TextArea) GetContentWidth() int {
+	if len(self.cells) == 0 {
+		return 0
+	}
+	last := self.cells[len(self.cells)-1]
+	return last.x + last.width
+}
+
 func (self *TextArea) ToggleOverwrite() {
 	self.overwrite = !self.overwrite
 }

pkg/gocui/view.go

@@ -1722,6 +1722,17 @@ func (v *View) RenderTextArea() {
 	newViewCursorX, newOriginX := updatedCursorAndOrigin(prevOriginX, width, cursorX)
 	newViewCursorY, newOriginY := updatedCursorAndOrigin(prevOriginY, height, cursorY)
 
+	contentWidth := v.TextArea.GetContentWidth()
+	usableWidth := width - 1
+	maxOriginX := contentWidth - usableWidth
+	if maxOriginX < 0 {
+		maxOriginX = 0
+	}
+	if newOriginX > maxOriginX {
+		newOriginX = maxOriginX
+		newViewCursorX = cursorX - newOriginX
+	}
+
 	v.SetCursor(newViewCursorX, newViewCursorY)
 	v.SetOrigin(newOriginX, newOriginY)
 }

pkg/gocui/view_test.go

@@ -120,6 +120,40 @@ func TestUpdatedCursorAndOrigin(t *testing.T) {
 	}
 }
 
+func TestRenderTextAreaClampsScrollOffset(t *testing.T) {
+	// View with inner width 10: x0=0, x1=11 → Width=12, InnerWidth=10
+	v := NewView("name", 0, 0, 11, 0, OutputNormal)
+	v.Editable = true
+
+	// Type 15 characters to overflow the viewport
+	for i := 0; i < 15; i++ {
+		v.TextArea.TypeCharacter("a")
+	}
+	// Cursor is at position 15, content width is 15
+	cursorX, _ := v.TextArea.GetCursorXY()
+	assert.Equal(t, 15, cursorX)
+
+	// Simulate scrolling: set origin so viewport shows positions 6-15
+	v.SetOrigin(6, 0)
+	v.RenderTextArea()
+	originX, _ := v.Origin()
+	assert.Equal(t, 6, originX)
+
+	// Now delete 11 characters so content is only 4 chars wide
+	for i := 0; i < 11; i++ {
+		v.TextArea.BackSpaceChar()
+	}
+	// Cursor is at position 4, content width is 4
+	cursorX, _ = v.TextArea.GetCursorXY()
+	assert.Equal(t, 4, cursorX)
+	assert.Equal(t, 4, v.TextArea.GetContentWidth())
+
+	// After rendering, origin should be clamped to 0 since content (4) < viewport (10)
+	v.RenderTextArea()
+	originX, _ = v.Origin()
+	assert.Equal(t, 0, originX, "origin should be clamped to 0 when content is narrower than viewport")
+}
+
 func TestAutoRenderingHyperlinks(t *testing.T) {
 	v := NewView("name", 0, 0, 10, 10, OutputNormal)
 	v.AutoRenderHyperLinks = true