Account for the inclusion gutter when mapping view columns to content

Search matches beside the inclusion gutter are highlighted in the wrong
place, and hovering over or clicking a hyperlink there acts on the wrong
cell. The draw loop starts the content after the gutter, but the code
that maps a view column back to a column of the content only adds the
horizontal origin and ignores the gutter.

Add a helper that does both, and use it for search highlights, hover
and clicks.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

pkg/gocui/gui.go

@@ -1793,7 +1793,7 @@ func (g *Gui) onKey(ev *GocuiEvent) error {
 		newCx := mx - v.x0 - 1
 		newCy := my - v.y0 - 1
 		// newX and newY are relative to the view's content, independent of its scroll position
-		newX := newCx + v.ox
+		newX := v.contentX(newCx)
 		newY := newCy + v.oy
 		// if view is editable don't go further than the furthest character for that line
 		if v.Editable {

pkg/gocui/view.go

@@ -2008,10 +2008,17 @@ func (v *View) viewLineLengthIgnoringTrailingBlankLines() int {
 	return 0
 }
 
+// contentX returns the column of the view's content that is drawn at column x of the
+// view. The content starts after the inclusion gutter, and is scrolled by the view's
+// horizontal origin.
+func (v *View) contentX(x int) int {
+	return x - v.inclusionGutterWidth() + v.ox
+}
+
 func (v *View) isPatternMatchedRune(x, y int) (bool, bool) {
 	for i, pos := range v.searcher.searchPositions {
 		adjustedY := y + v.oy
-		adjustedX := x + v.ox
+		adjustedX := v.contentX(x)
 		if adjustedY == pos.Y && adjustedX >= pos.XStart && adjustedX < pos.XEnd {
 			return true, i == v.searcher.currentSearchIndex
 		}
@@ -2022,7 +2029,7 @@ func (v *View) isPatternMatchedRune(x, y int) (bool, bool) {
 func (v *View) isHoveredHyperlink(x, y int) bool {
 	if v.UnderlineHyperLinksOnlyOnHover && v.hoveredHyperlink != nil {
 		adjustedY := y + v.oy
-		adjustedX := x + v.ox
+		adjustedX := v.contentX(x)
 		return adjustedY == v.hoveredHyperlink.Y && adjustedX >= v.hoveredHyperlink.XStart && adjustedX < v.hoveredHyperlink.XEnd
 	}
 	return false
@@ -2846,7 +2853,7 @@ func (v *View) onMouseMove(x int, y int) {
 	newCx := x - v.x0 - 1
 	newCy := y - v.y0 - 1
 	// newX and newY are relative to the view's content, independent of its scroll position
-	newX := newCx + v.ox
+	newX := v.contentX(newCx)
 	newY := newCy + v.oy
 
 	if newY >= 0 && newY <= len(v.viewLines)-1 && newX >= 0 && newX <= len(v.viewLines[newY].line)-1 {

pkg/gocui/view_test.go

@@ -1267,10 +1267,7 @@ func TestSearchMatchBesideTheInclusionGutter(t *testing.T) {
 	}
 	// The row reads "✓ 01234567", so the match is at view columns 5 and 6.
 	assert.Equal(t,
-		/* EXPECTED:
 		".....##...",
-		ACTUAL: */
-		"...##.....",
 		highlightedColumns(1))
 }
 
@@ -1299,10 +1296,7 @@ func TestHoveredHyperlinkBesideTheInclusionGutter(t *testing.T) {
 		return s
 	}
 	assert.Equal(t,
-		/* EXPECTED:
 		"....____..",
-		ACTUAL: */
-		"..____....",
 		underlinedColumns(1))
 }
 
@@ -1328,10 +1322,7 @@ func TestClickHyperlinkBesideTheInclusionGutter(t *testing.T) {
 		Key: NewKeyName(MouseLeft),
 	}))
 	assert.Equal(t,
-		/* EXPECTED:
 		[]string{"https://example.com"},
-		ACTUAL: */
-		[]string{},
 		opened)
 }