diff --git a/src/window.cc b/src/window.cc
index 0e9991628..aa9f28242 100644
--- a/src/window.cc
+++ b/src/window.cc
@@ -234,7 +234,7 @@ ByteCoord find_buffer_coord(const DisplayLine& line, const Buffer& buffer,
 }
 }
 
-CharCoord Window::display_position(ByteCoord coord)
+CharCoord Window::display_position(ByteCoord coord) const
 {
     LineCount l = 0;
     for (auto& line : m_display_buffer.lines())
@@ -247,6 +247,13 @@ CharCoord Window::display_position(ByteCoord coord)
     return { 0, 0 };
 }
 
+ByteCoord Window::buffer_coord(CharCoord coord) const
+{
+    if (0_line <= coord.line and coord.line < m_display_buffer.lines().size())
+        return find_buffer_coord(m_display_buffer.lines()[(int)coord.line], buffer(), coord.column);
+    return { 0, 0 };
+}
+
 ByteCoord Window::offset_coord(ByteCoord coord, CharCount offset)
 {
     return buffer().offset_coord(coord, offset);
diff --git a/src/window.hh b/src/window.hh
index 54973d2b9..0ad70a549 100644
--- a/src/window.hh
+++ b/src/window.hh
@@ -31,7 +31,8 @@ public:
     void scroll(CharCount offset);
     void update_display_buffer(const Context& context);
 
-    CharCoord display_position(ByteCoord coord);
+    CharCoord display_position(ByteCoord coord) const;
+    ByteCoord buffer_coord(CharCoord coord) const;
 
     Highlighter& highlighters() { return m_highlighters; }