Américo, Tablet stylus pressure is a physical quantity, assuming that all devices give you linear pressure, and you want all devices to "feel the same", then there are only those two correction curves that make sense:
http://maxy.homeip.net/misc/tablet-pressure-gain.png This is called a "gain" or "constant gain". Non-linear (smooth or not) curves will not help making the devices "feel the same". (Except to correct a non-linear hardware response. But if you have that, I would consider that a hardware bug, or maybe you have another non-linear pressure curve mapping in a driver somewhere.) The smooth curves only help to keep the full pressure range of the hardware usable ("do something"). You have to decide what your goal is - map the full range of hardware pressure levels to values between 0.0 and 1.0, or have the a consistent pressure response accross all devices. The piecewise-linear curves are coded quite deep inside MyPaint, and we probably have to keep them linear internally (for the brushes at least, not for the global pressure mapping). But often a linear approximation is good enough. We could make the GUI non-linear where it makes sense (e.g. a pressure gamma slider, if that helps). If we would calculate a piecewise-linear approximation internally, you wouldn't notice the difference - but have a nicer GUI to generate the points for you. Regards Martin On Fri, Jan 04, 2013 at 12:16:39PM -0200, José Américo Gobbo wrote: > Hi all, > nn these days I and Mozart Couto we doing a full immersion in Mypaint 1.1. > After a bit discussion I think useful propose some improvements in the > graphs used in Mypaint. > Per example, in the preferences to have a graph more precise and with > smooth feature: > [image: Inline image 1] > I think that will be more easy to control the pressure behavior of the > tablets. > > In the Quick Brush Settings to have a gain factor graph: > [image: Inline image 2] > This curve would be a general behavior of loss and / or gain on the brushes > ... but the curve is applied over all settings recorded on Brush Settings > Editor. > > Many times, while we're working... we need modify a bit the sensibility and > this control will be very useful. This instance also will be useful to > correct the gain differences between the different tablets without modify > the original aspects of the brush design. > > Per example... some of yours brushes, mainly the pencils don't are usable > with the original settings on my tablets... an old intuos 2 and a Monoprice > 10x6. Mozart Couto has observed the same behavior... and I asked him to > make some videos of this behavior with different tablets... he has > different tablets, genius, uc logic, trust and wacoms... Another thing is > more easy understand a graph for this gain factor only with the quadrant > positive, x and y >= zero. > > Thanks > americo > _______________________________________________ > Mypaint-discuss mailing list > [email protected] > https://mail.gna.org/listinfo/mypaint-discuss -- Martin Renold _______________________________________________ Mypaint-discuss mailing list [email protected] https://mail.gna.org/listinfo/mypaint-discuss
