[PATCH inputproto multitouch] State that future touch IDs are indeterminate

Chase Douglas chase.douglas at canonical.com
Mon Dec 12 10:56:40 PST 2011

This just makes it absolutely clear that clients should not make any
assumptions about future touch ID values.

I also added "strictly monotonically" increasing to the definition of
touch IDs. It's a more precise definition of the protocol.

Signed-off-by: Chase Douglas <chase.douglas at canonical.com>
 specs/XI2proto.txt |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/specs/XI2proto.txt b/specs/XI2proto.txt
index ba5f7b7..8e4f948 100644
--- a/specs/XI2proto.txt
+++ b/specs/XI2proto.txt
@@ -2149,9 +2149,11 @@ may not be the logical center of the touch.
 Touch tracking IDs are provided in the detail field of touch events. Its
 value is always provided in every touch event. Tracking IDs are
-represented as unsigned 32-bit values and increase in value for each new
-touch, wrapping back to 0 upon reaching the numerical limit of IDs. IDs are
-globally unique.
+represented as unsigned 32-bit values and increase strictly monotonically in
+value for each new touch, wrapping back to 0 upon reaching the numerical limit
+of IDs. The distance between two touch IDs is indeterminate. Clients may not
+assume that any future touches will have specific touch IDs. IDs are globally
 Touch events do not generate enter/leave events.

More information about the xorg-devel mailing list