From: Derek Foreman <derekf@osg.samsung.com>
Date: Thu, 30 Oct 2014 21:34:15 +0000 (-0500)
Subject: evdev: add DPI to evdev calculations
X-Git-Tag: 0.7.0~87
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=79898da377ba58857be0bd104de694eb1e66f41f;p=platform%2Fupstream%2Flibinput.git

evdev: add DPI to evdev calculations

Assume "normal" mice are 400DPI, and that all calculations should be
normalized to this before being fed into the filter.

There isn't yet a way to configure a device's DPI.

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

diff --git a/src/evdev.c b/src/evdev.c
index 1f51b4af..3aa87a75 100644
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -42,6 +42,8 @@
 
 #define DEFAULT_AXIS_STEP_DISTANCE 10
 #define DEFAULT_MIDDLE_BUTTON_SCROLL_TIMEOUT 200
+/* The HW DPI rate we normalize to before calculating pointer acceleration */
+#define DEFAULT_MOUSE_DPI 400
 
 enum evdev_key_type {
 	EVDEV_KEY_TYPE_NONE,
@@ -205,8 +207,8 @@ evdev_flush_pending_event(struct evdev_device *device, uint64_t time)
 	case EVDEV_NONE:
 		return;
 	case EVDEV_RELATIVE_MOTION:
-		motion.dx = device->rel.dx;
-		motion.dy = device->rel.dy;
+		motion.dx = device->rel.dx / ((double)device->dpi / DEFAULT_MOUSE_DPI);
+		motion.dy = device->rel.dy / ((double)device->dpi / DEFAULT_MOUSE_DPI);
 		device->rel.dx = 0;
 		device->rel.dy = 0;
 
@@ -1293,6 +1295,7 @@ evdev_device_create(struct libinput_seat *seat,
 	device->devname = libevdev_get_name(device->evdev);
 	device->scroll.threshold = 5.0; /* Default may be overridden */
 	device->scroll.direction = 0;
+	device->dpi = DEFAULT_MOUSE_DPI;
 
 	matrix_init_identity(&device->abs.calibration);
 	matrix_init_identity(&device->abs.usermatrix);
diff --git a/src/evdev.h b/src/evdev.h
index 9e846238..666c8dc8 100644
--- a/src/evdev.h
+++ b/src/evdev.h
@@ -136,6 +136,7 @@ struct evdev_device {
 		void (*change_to_left_handed)(struct evdev_device *device);
 	} buttons;
 
+	int dpi; /* HW resolution */
 	/* The number of times libevdev processes a SYN_DROPPED, so we can
 	 * stop logging them to avoid flooding the logs. */
 	int syn_drops_received;