On Tue, Dec 12, 2017 at 4:49 PM, Ping Cheng <pingli...@gmail.com> wrote: > Thank you for your cleanup work, Jason. The first two patches look fine. > This one definitely needs some testing to make sure it achieves what you > planned for. > > Assuming your testing of this patch was successfully, the whole set is; > > Reviewed-by: Ping Cheng <ping.ch...@wacom.com> > > With one question below. > > On Fri, Dec 8, 2017 at 1:55 PM, Jason Gerecke <killert...@gmail.com> wrote: >> >> Coordinate averaging is useful for producing smooth strokes, but this >> averaging can cause button events to be sent at the wrong location. >> In particular, when making a series of quick strokes with an AES pen, >> the actual location the pen contacts the display can be some distance >> away from the first (low-quality) position report. This can result in >> "hook" artifacts if it is still influencing the averaged pointer >> position when the pen goes down. >> >> To prevent these artifacts from appearing, we reset the averaging filter >> whenever a button is pressed. This ensures that button events are sent >> at the pen's actual location, plus or minus some (much smaller) noise. >> Resetting the filter should not significantly impact stroke quality since >> buttons are rarely pressed mid-stroke. >> >> https://sourceforge.net/p/linuxwacom/bugs/338/ >> >> Signed-off-by: Jason Gerecke <jason.gere...@wacom.com> >> --- >> src/wcmCommon.c | 9 +++++++++ >> 1 file changed, 9 insertions(+) >> >> diff --git a/src/wcmCommon.c b/src/wcmCommon.c >> index 900544b..e515078 100644 >> --- a/src/wcmCommon.c >> +++ b/src/wcmCommon.c >> @@ -1241,6 +1241,15 @@ static void commonDispatchDevice(InputInfoPtr >> pInfo, >> if (!priv->oldState.proximity) >> wcmResetSampleCounter(pChannel); >> >> + /* Reset filter whenever a button is pressed to > > > Shouldn't we do it for button release too? Some actions may be trigged by > button release instead. >
Hmm, that's an interesting question... Having actions trigger at the actual pen position instead of its averaged position sounds valuable, but I do worry a little that it could result in hooks at the end of strokes. I'm not sure it would be a problem with a normal amount of averaging, but it would definitely be more pronounced as its increased. I'll have to do some experimentation... Jason --- Now instead of four in the eights place / you’ve got three, ‘Cause you added one / (That is to say, eight) to the two, / But you can’t take seven from three, / So you look at the sixty-fours.... >> + * ensure the clicks are sent at the pen's actual >> + * position. This prevents "hooks" from appearing >> + * at the beginning of series of rapidly-drawn or >> + * highly-averaged strokes. >> + */ >> + if ((priv->oldState.buttons ^ filtered.buttons) & >> filtered.buttons) > > > So, is the second filtered.buttons necessary above? > > Cheers, > Ping > >> + wcmResetSampleCounter(pChannel); >> + >> wcmFilterCoord(common,pChannel,&filtered); >> } >> >> -- >> 2.15.1 >> > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Linuxwacom-devel mailing list Linuxwacom-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxwacom-devel
