Follow-up Comment #5, bug #21735 (project mypaint):
Well changing that to -1 didn't work at all-- just made things worse. So, I
decided to try The Gimp and see if this behavior existed there... Gimp 2.8..
downloaded a tilt brush. It acts the same! Finally I try another program--
Krita. Download a tilt brush-- it works fine! The tilt is consistent
regardless of ascension. Somehow Krita is getting it right. I checked out
the source and I see almost the exact same code as MyPaint
qreal KisPaintInformation::declination(const KisPaintInformation& info, qreal
maxTiltX, qreal maxTiltY, bool normalize)
{
qreal xTilt = qBound(qreal(-1.0), info.xTilt() / maxTiltX , qreal(1.0));
qreal yTilt = qBound(qreal(-1.0), info.yTilt() / maxTiltY , qreal(1.0));
qreal e;
if (fabs(xTilt) > fabs(yTilt)) {
e = sqrt(qreal(1.0) + yTilt*yTilt);
} else {
e = sqrt(qreal(1.0) + xTilt*xTilt);
}
qreal cosAlpha = sqrt(xTilt*xTilt + yTilt*yTilt)/e;
qreal declination = acos(cosAlpha); // in radians in [0, 0.5 * PI]
// mapping to 0.0..1.0 if normalize is true
return normalize ? (declination / (M_PI * qreal(0.5))) : declination;
}
I tried adjusting mypaint code to look more like this, and even leave the
values in Radians and normalized. I adjusted my brush in Mypaint to use
values from 0 to 1 (instead of 0 to 90) and.... it was still weird had more
tilt N/S versus E/W.
Back to the drawing board. (no pun intended)
_______________________________________________________
Reply to this item at:
<http://gna.org/bugs/?21735>
_______________________________________________
Message sent via/by Gna!
http://gna.org/
_______________________________________________
Mypaint-bugs mailing list
[email protected]
https://mail.gna.org/listinfo/mypaint-bugs
