On 05/22/2014 08:23 PM, Dmitry Torokhov wrote: > Hi Ferruh, > > On Thu, May 22, 2014 at 02:03:40PM +0300, Ferruh Yigit wrote: >> Hi, >> >> What is the metric of ABS_MT_TOUCH_MAJOR / ABS_MT_WIDTH_MAJOR events? >> >> The Linux documentation >> <https://www.kernel.org/doc/Documentation/input/multi-touch-protocol.txt> says: >> "The length of the major axis of the contact. The length should be given >> in surface units. ..." >> >> What does "surface units" means, is it millimeter or pixels? > It is whatever unit the device reports, similarly to ABS_MT_POSITION_X > and ABS_MT_POSITION_Y. Userspace can use EVIOCGABS to map device units > onto common units. > > From include/uapi/linux/input.h (struct input_absinfo): > > * Resolution for main axes (ABS_X, ABS_Y, ABS_Z) is reported in > * units per millimeter (units/mm), resolution for rotational axes > * (ABS_RX, ABS_RY, ABS_RZ) is reported in units per radian. > > Hope this helps. > Hi Dmitry, I understand this works for Dmitry ABS_X, ABS_Y, touchscreen reports between 0..A, screen resolution is 0..B, a mapping can be done 0..A -> 0..B But for ABS_MT_TOUCH_MAJOR how this scaling can be done, touchscreen reports between 0..A, do we know the min/max values for application side? -- Thanks, ferruh -- 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
