Move get_screen_dpi to libdocument

[evince.git] / libdocument / ev-document-misc.c

diff --git a/libdocument/ev-document-misc.c b/libdocument/ev-document-misc.c
index 14bc3a354a3d86cd122293499fecf7e1e91020b9..0a23394c1ba5c5644215a98fdfbaef1e7cae710e 100644 (file)
--- a/libdocument/ev-document-misc.c
+++ b/libdocument/ev-document-misc.c
@@ -21,6 +21,7 @@
 #include <config.h>
 
 #include <string.h>
+#include <math.h>
 
 #include <gtk/gtk.h>
 
@@ -363,3 +364,17 @@ ev_document_misc_invert_pixbuf (GdkPixbuf *pixbuf)
                }
        }
 }
+
+gdouble
+ev_document_misc_get_screen_dpi (GdkScreen *screen)
+{
+       gdouble dp, di;
+
+       /*diagonal in pixels*/
+       dp = hypot (gdk_screen_get_width (screen), gdk_screen_get_height (screen));
+
+       /*diagonal in inches*/
+       di = hypot (gdk_screen_get_width_mm(screen), gdk_screen_get_height_mm (screen)) / 25.4;
+
+       return (dp / di);
+}