diff options
Diffstat (limited to 'src/evdev-tablet.c')
| -rw-r--r-- | src/evdev-tablet.c | 52 |
1 files changed, 25 insertions, 27 deletions
diff --git a/src/evdev-tablet.c b/src/evdev-tablet.c index 21963ccd..62c23b83 100644 --- a/src/evdev-tablet.c +++ b/src/evdev-tablet.c @@ -353,30 +353,20 @@ static inline double normalize_pressure(const struct input_absinfo *absinfo, struct libinput_tablet_tool *tool) { - int offset; - double range; - double value; - /** - * If the tool has a pressure offset, we use that as the lower bound - * for the scaling range. If not, we use the upper threshold as the - * lower bound, so once we get past that minimum physical pressure - * we have logical 0 pressure. + * Note: the upper threshold takes the offset into account so that + * |- 4% -| + * min |------X------X-------------------------| max + * | | + * | + upper threshold / tip trigger + * +- offset and lower threshold * - * This means that there is a small range (lower-upper) where - * different physical pressure (default: 1-5%) result in the same - * logical pressure. This is, hopefully, not noticeable. - * - * Note that that lower-upper range gives us a negative pressure, so - * we have to clip to 0 for those. + * The axis is scaled into the range [lower, max] so that the lower + * threshold is 0 pressure. */ - - if (tool->pressure.has_offset) - offset = tool->pressure.offset; - else - offset = tool->pressure.threshold.upper; - range = absinfo->maximum - offset; - value = (absinfo->value - offset) / range; + int base = tool->pressure.threshold.lower; + double range = absinfo->maximum - base; + double value = (absinfo->value - base) / range; return max(0.0, value); } @@ -1255,7 +1245,10 @@ sanitize_pressure_distance(struct tablet_dispatch *tablet, if (!pressure_changed && !distance_changed) return; - tool_in_contact = (pressure->value > tool->pressure.offset); + /* Note: this is an arbitrary "in contact" decision rather than "tip + * down". We use the lower threshold as minimum pressure value, + * anything less than that gets filtered away */ + tool_in_contact = (pressure->value > tool->pressure.threshold.lower); /* Keep distance and pressure mutually exclusive */ if (distance && @@ -1327,7 +1320,7 @@ detect_pressure_offset(struct tablet_dispatch *tablet, */ if (tool->pressure.has_offset) { if (offset < tool->pressure.offset) - tool->pressure.offset = offset; + goto set_offset; return; } @@ -1359,9 +1352,17 @@ detect_pressure_offset(struct tablet_dispatch *tablet, tablet_tool_type_to_string(tool->type), tool->serial, HTTP_DOC_LINK); +set_offset: tool->pressure.offset = offset; tool->pressure.has_offset = true; - tool->pressure.threshold.lower = pressure->minimum; + + /* Adjust the tresholds accordingly - we use the same gap (4% in + * device coordinates) between upper and lower as before which isn't + * technically correct (our range shrunk) but it's easy to calculate. + */ + int gap = tool->pressure.threshold.upper - tool->pressure.threshold.lower; + tool->pressure.threshold.lower = offset; + tool->pressure.threshold.upper = offset + gap; } static void @@ -1392,9 +1393,6 @@ detect_tool_contact(struct tablet_dispatch *tablet, } pressure = p->value; - if (tool->pressure.has_offset) - pressure -= (tool->pressure.offset - p->minimum); - if (pressure <= tool->pressure.threshold.lower && tablet_has_status(tablet, TABLET_TOOL_IN_CONTACT)) { tablet_set_status(tablet, TABLET_TOOL_LEAVING_CONTACT); |