tools: print the formula to calculate resolutions

And encourage users to move at least 25cm, makes it a lot easier to pick the
resolution.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

diff --git a/tools/mouse-dpi-tool.c b/tools/mouse-dpi-tool.c
index 2bbaca5..5fbc63d 100644 (file)
--- a/tools/mouse-dpi-tool.c
+++ b/tools/mouse-dpi-tool.c
@@ -181,6 +181,9 @@ print_summary(struct measurements *m)
                printf("%8dmm   %8.2fin %8ddpi\n",
                       (int)(inch * 25.4), inch, res);
        }
+       printf("If your resolution is not in the list, calculate it with:\n"
+              "\tresolution=%d/inches, or\n"
+              "\tresolution=%d/(mm * 25.4)\n", m->distance, m->distance);
 }
 
 static inline const char*
@@ -236,7 +239,7 @@ main (int argc, char **argv) {
        libevdev_grab(dev, LIBEVDEV_UNGRAB);
 
        printf("Mouse %s on %s\n", libevdev_get_name(dev), path);
-       printf("Move the device along the x-axis.\n");
+       printf("Move the device 250mm/10in or more along the x-axis.\n");
        printf("Pause 3 seconds before movement to reset, Ctrl+C to exit.\n");
        setbuf(stdout, NULL);