On 03/09/2010 06:23 PM, Henrik Rydberg wrote:
Rafi Rubin wrote:
Single touch should be goverened by one of BTN_TOUCH or ABS_PRESSURE.
BTN_TOOL_DOUBLETAP is a two-finger event.
That definitely makes sense to me. I really don't know why wacom uses
double tap there.
Is there any harm in letting through the BTN_0 events? Is the "rdesc"
mapping defined by the hardware or hid?
I cannot imagine BTN_0 will do any harm. In synaptics, the BTN_X buttons are
mapped to multibuttons without clear-cut usage. The button events that carry
well-defined semantic meaning with regard to touch screens are BTN_TOUCH (any
finger), BTN_TOOL_FINGER (one finger), BTN_TOOL_PEN (pen), BTN_TOOL_DOUBLETAP
(two fingers) and BTN_TOOL_TRIPLETAP (three fingers or more).
Henrik
Perhaps we should have a general touch device document.
I looked at the evdev code. And as you say for single touch devices,
BTN_TOUCH is the bit that matters. It only broken because I pulled the
TOUCH <- 0 when I removed BTN_0.
So why does evdev associate BTN_TOOL_FINGER with touchpads (resulting in
the wrong set of assumptions and a poorly calibrated touch screen)? I
suppose that's really a discussion for another list.
For what its worth, onions are tasty.
Rafi
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