input: add area transformation for tablet coordinates

diff --git a/src/input/tablet.c b/src/input/tablet.c
index 3ea70c4b36effbff2e991bb740d4cfb0dd257bd1..662ce0c70ffc7c2e65290cd481c503b6fc2b9bb5 100644 (file)
--- a/src/input/tablet.c
+++ b/src/input/tablet.c
@@ -11,6 +11,34 @@
 #include "input/cursor.h"
 #include "input/tablet.h"
 
+static void
+adjust_for_tablet_area(double tablet_width, double tablet_height,
+               struct wlr_fbox box, double *x, double *y)
+{
+       if ((!box.x && !box.y && !box.width && !box.height)
+                       || !tablet_width || !tablet_height) {
+               return;
+       }
+
+       if (!box.width) {
+               box.width = tablet_width - box.x;
+       }
+       if (!box.height) {
+               box.height = tablet_height - box.y;
+       }
+
+       if (box.x + box.width <= tablet_width) {
+               const double max_x = 1;
+               double width_offset = max_x * box.x / tablet_width;
+               *x = (*x - width_offset) * tablet_width / box.width;
+       }
+       if (box.y + box.height <= tablet_height) {
+               const double max_y = 1;
+               double height_offset = max_y * box.y / tablet_height;
+               *y = (*y - height_offset) * tablet_height / box.height;
+       }
+}
+
 static void
 adjust_for_rotation(enum rotation rotation, double *x, double *y)
 {
@@ -50,6 +78,8 @@ handle_axis(struct wl_listener *listener, void *data)
 
                double x = tablet->x;
                double y = tablet->y;
+               adjust_for_tablet_area(tablet->tablet->width_mm, tablet->tablet->height_mm,
+                       rc.tablet.box, &x, &y);
                adjust_for_rotation(rc.tablet.rotation, &x, &y);
                cursor_emulate_move_absolute(tablet->seat, &ev->tablet->base, x, y, ev->time_msec);
        }