diff --git a/redo/sizing_windows.c b/redo/sizing_windows.c
index 133cbcc..e6f27a6 100644
--- a/redo/sizing_windows.c
+++ b/redo/sizing_windows.c
@@ -38,3 +38,24 @@ void moveWindow(HWND hwnd, int x, int y, int width, int height)
 	if (MoveWindow(hwnd, x, y, width, height, TRUE) == 0)
 		xpanic("error setting window/control rect", GetLastError());
 }
+
+LONG controlTextLength(HWND hwnd, LPWSTR text)
+{
+	HDC dc;
+	HFONT prev;
+	SIZE size;
+
+	dc = GetDC(hwnd);
+	if (dc == NULL)
+		xpanic("error getting DC of control for text length", GetLastError());
+	prev = SelectObject(dc, controlFont);
+	if (prev == NULL)
+		xpanic("error setting control font to DC for text length", GetLastError());
+	if (GetTextExtentPoint32W(dc, text, wcslen(text), &size) == 0)
+		xpanic("error actually getting text length", GetLastError());
+	if (SelectObject(dc, prev) != controlFont)
+		xpanic("error restoring previous control font to DC for text length", GetLastError());
+	if (ReleaseDC(hwnd, dc) == 0)
+		xpanic("error releasing DC of control for text length", GetLastError());
+	return size.cx;
+}
diff --git a/redo/winapi_windows.h b/redo/winapi_windows.h
index 4bd035c..12e5ddf 100644
--- a/redo/winapi_windows.h
+++ b/redo/winapi_windows.h
@@ -18,6 +18,8 @@
 #include <commctrl.h>
 #include <stdint.h>
 #include <uxtheme.h>
+#include <string.h>
+#include <wchar.h>
 
 /* global messages unique to everything */
 enum {
@@ -68,6 +70,7 @@ extern int baseX;
 extern int baseY;
 extern void calculateBaseUnits(HWND);
 extern void moveWindow(HWND, int, int, int, int);
+extern LONG controlTextLength(HWND, LPWSTR);
 
 /* window_windows.c */
 extern DWORD makeWindowWindowClass(char **);