User:Americo/learning

Learning about brushes

Nomenclatura
About Speed1, Speed2

To stay on topic for a bit, here is what I think could be easily done for speed1/speed2 to make the situation slightly better:


 * make the input names translatable (the same way setting names already are)
 * rename speed1 ==> fine speed (in the GUI only)
 * rename speed2 ==> gross speed (in the GUI only)

In case anyone wants to do something about that.

[I've extract this conversation between Martin and Luka, Mypaint-discuss Digest, Vol 18, Issue 11]

Sat 18 Dec 2009 | Talk IRC about Brush Input Settings [charts and range 'x' parameter]
Ramon_GPS: need to talk with him about some parameters

maxy: yes I am, but I haven't read all my mail yet

Ramon_GPS: ok, i would like to ask for some help

Ramon_GPS: is there any documentation about the parameters?

jonnor Just ask and people will answer when they can.

maxy: Ramon_GPS:: can you read the tooltips?

Ramon_GPS: ok I cant understand some things

maxy: when you hover over a parameter, a tooltip appears

Ramon_GPS: i am making tests to understand the behasviour of the graph

Ramon_GPS: for exmaple i read about lineature? or something behind opacitiy

maxy: lineature? no idea what you mean

Ramon_GPS: there is opacity, opacitymultyply ,which is the following?

Ramon_GPS: cant remember his englsish name

maxy: "opaque linearize"

maxy: just leave that value on the default

Ramon_GPS: some graphs are not centered in the graph as i have seen Ramon_GPS: i cant understand this 2 axis graph well

/* Size = Radius */ Ramon_GPS: so where is the documentation?

maxy: No. It's a function. X axis is input, Y axis is output.

maxy: eg. for mapping size to pressure: if you want to know what size you get at pressure 0.5, then you search the value 0.5 along the X axis, and see where the curve is at that value on the Y axis.

maxy: and the values of all the different curves that you have for "size" are added together.

maxy: (eg. you have a pressure-->size mapping, a speed1-->size mapping, a stroke-->size mapping, they area added together)

/* Like as my charts observations */

/* Semi-transparent box */ Ramon_GPS: why is there semitransparent box in the middle of the graph?

maxy: it marks the "neutral" value for that input.

Ramon_GPS: the 0?

maxy: no

maxy: for example, for the input "pressure", the neutral pressure is set to 0.4, which is where the gray box is.

maxy: if your curve goes through the gray box (that is, the ouptut is zero at the neutral value), then you do not modify the setting at the "normal" value.

maxy: this is what automatically happens when you use the sliders (not the curve) /* ''what is the sliders? they are those two dialogues for it inputs the parameter range on the x axis'' */ maxy: for example, if you make the radius depend on the speed input (using only the "by speed" slider, not the curve)

maxy: then the "normal" radius (the radius at "neutral" speed) is not changed, only if speed is below or above neutral

maxy: And no, this is not documented anywhere. /* ''the dialogues inputs for neutral marker is used for setup the sensibility of output in functions of 'x' range parameter, p.e., how more short this range more is the sensibility or grown tax of output, y axis, if we have, pressure x size, more larger will be the brush for each increment in x axis. A preview of the brush in basis a fixed increment could be very interesting'' */ maxy: (You can also simply ignore the grey box, it's was supposed to be a helpful visual orientation point, it doesn't affect the mapping at all.) /* ''is right, but if you use the curves for setup the behavior this marker is very useful for how you can adjust the sensibility function, pe. if you make a curve y=k (constant), the marker is not useful (y=mx+b => y=0.x+b)'' */

Charts [pressure x size(radius)] for neutral points 0.4, 0.2 and 0.7: (*) adjective subjective, only for demonstrate the growing tax.
 * Chart 2 Pn=0.4, y=3.33x-1.33 (normal* increment tax output, y axis)
 * Chart 1 Pn=0.2, y=2.5x-0.5 (soft* increment tax output, y axis)
 * Chart 3 Pn=0.7, y=6.67x-4.37 (heavy* increment tax output, y axis)

Ramon_GPS: wo woo  that is complex, interesting but complex

maxy: would it help if we simply remove the grey box?

Ramon_GPS: haha not real solution

Ramon_GPS: i see the gray box as a reference too

Ramon_GPS: i think the bottom sliders in X axis are for "cut" or put "cut values" about pressure

Ramon_GPS: because we can ignore some of the performance of the pen

Ramon_GPS: for example we can cut the right value of the bottom slider to make that we dont have to push the pen too heavy to get all the range

/* minor x parameter range more heavy change the brush; major x range parameter more softness change the brush. */

/* '''about the tips... create a document with the definitions settings brushes contained in the tips''' * Ramon_GPS: Documentation will be a lot helpful, understanding the behaviour of parameters you get the "power"

maxy: if there is a way to make the GUI more self-explaining, I would prefer that to external documentation

maxy: but it would be much better to have external documentation than nothing

Ramon_GPS: ok i understand, maybe with some examples with the graph and the effect that produces

Ramon_GPS: wich is better to map opacity to pressure?

Ramon_GPS: opacity itself or opacity multiply?

Ramon_GPS: i have seen that thay work maybe in combination? because something multiplied by 0 is always 0 so you must add some of both

Ramon_GPS: is that right? /* opaque_linearize and opaque_multiply */ maxy: Ramon_GPS:: both opacity and opacity multiply do exactly the same thing (and the results are multiplied with each other).

maxy: I think there is a hint about intended usage in the tooltips.

Ramon_GPS: ok

maxy: maybe I can say it like that: the main idea is to always multiply the opacity value with zero when there is no pressure.

maxy: no matter what "opacity" the user selects

= Troubleshooting =

When I watch some brushes, ever the max and min of 'y' axis is unbalanced... but if you change the value in the slider, then these values become equal.
 * How works the chart slider on 'y' axis?