evdev: Fix absolute coordinate transform formula

Since the device min/max x/y coordinates are inclusive, to get the
width/height one need to add one to (min x/y - max x/y).

Signed-off-by: Jonas Ådahl <jadahl@gmail.com>

diff --git a/src/evdev.c b/src/evdev.c
index cb83a1f..2bc301b 100644 (file)
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -91,8 +91,8 @@ evdev_device_transform_x(struct evdev_device *device,
                         li_fixed_t x,
                         uint32_t width)
 {
-       return (x - device->abs.min_x) * width /
-               (device->abs.max_x - device->abs.min_x);
+       return (x - li_fixed_from_int(device->abs.min_x)) * width /
+               (device->abs.max_x - device->abs.min_x + 1);
 }
 
 li_fixed_t
@@ -100,8 +100,8 @@ evdev_device_transform_y(struct evdev_device *device,
                         li_fixed_t y,
                         uint32_t height)
 {
-       return (y - device->abs.min_y) * height /
-               (device->abs.max_y - device->abs.min_y);
+       return (y - li_fixed_from_int(device->abs.min_y)) * height /
+               (device->abs.max_y - device->abs.min_y + 1);
 }
 
 static void