Some touch devices are capable of detecting the envelope or hull of the touches, but not the touches themselves. This patch adds the MT_TOOL_ENVELOPE touch type to be used for such devices. Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx> --- Hi all, This patch represents an MT solution for those devices that can detect and report some effects of dual touch, but cannot report individual contacts. Synaptics and elantech are two examples. Having the drivers report the bounding rectangle of the touches is useful in userland, since the information makes it possible to implement zooming gestures. At the same time, it would be confusing to send these envelope points as fingers, since they clearly are not. As a remedy, introduce MT_TOOL_ENVELOPE, which tells applications that care about details that these are not real fingers, at the same time as it allows gesture applications based on MT data to function without modification. Thanks, Henrik Documentation/input/multi-touch-protocol.txt | 5 +++-- include/linux/input.h | 2 ++ 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/Documentation/input/multi-touch-protocol.txt b/Documentation/input/multi-touch-protocol.txt index bdcba15..690dd11 100644 --- a/Documentation/input/multi-touch-protocol.txt +++ b/Documentation/input/multi-touch-protocol.txt @@ -240,7 +240,7 @@ ABS_MT_TOOL_TYPE The type of approaching tool. A lot of kernel drivers cannot distinguish between different tool types, such as a finger or a pen. In such cases, the event should be omitted. The protocol currently supports MT_TOOL_FINGER and -MT_TOOL_PEN [2]. +MT_TOOL_PEN and MT_TOOL_ENVELOPE [2]. ABS_MT_BLOB_ID @@ -312,7 +312,8 @@ where examples can be found. [1] With the extension ABS_MT_APPROACH_X and ABS_MT_APPROACH_Y, the difference between the contact position and the approaching tool position could be used to derive tilt. -[2] The list can of course be extended. +[2] ABS_MT_ENVELOPE contacts represent an envelope of the contacts rather +than the actual contacts. Used with older, not fully MT capable, devices. [3] Multitouch X driver project: http://bitmath.org/code/multitouch/. [4] See the section on event computation. [5] See the section on finger tracking. diff --git a/include/linux/input.h b/include/linux/input.h index dd7c0fc..329dc0e 100644 --- a/include/linux/input.h +++ b/include/linux/input.h @@ -848,6 +848,8 @@ struct input_keymap_entry { */ #define MT_TOOL_FINGER 0 #define MT_TOOL_PEN 1 +#define MT_TOOL_ENVELOPE 2 +#define MT_TOOL_MAX 2 /* * Values describing the status of a force-feedback effect -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
