1 files changed, 10 insertions, 1 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 9b5b7edf035..6ed5fd151d6 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -17622,6 +17622,15 @@ calc_pixel_width_or_height (res, it, prop, font, width_p, align_to)
           if (pixels > 0)
             {
               double ppi;
+#ifdef HAVE_WINDOW_SYSTEM
+              if (FRAME_WINDOW_P (it->f)
+                  && (ppi = (width_p
+                             ? FRAME_X_DISPLAY_INFO (it->f)->resx
+                             : FRAME_X_DISPLAY_INFO (it->f)->resy),
+                      ppi > 0))
+                return OK_PIXELS (ppi / pixels);
+#endif
+
               if ((ppi = NUMVAL (Vdisplay_pixels_per_inch), ppi > 0)
                   || (CONSP (Vdisplay_pixels_per_inch)
                       && (ppi = (width_p
@@ -23056,7 +23065,7 @@ of the top or bottom of the window.  */);
   scroll_margin = 0;
 
   DEFVAR_LISP ("display-pixels-per-inch",  &Vdisplay_pixels_per_inch,
-    doc: /* Pixels per inch on current display.
+    doc: /* Pixels per inch value for non-window system displays.
 Value is a number or a cons (WIDTH-DPI . HEIGHT-DPI).  */);
   Vdisplay_pixels_per_inch = make_float (72.0);