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Bug 768206 - Paint Dynamics and Inverted curves - print strokes with value intermediate to value equal zero
Paint Dynamics and Inverted curves - print strokes with value intermediate to...
Status: RESOLVED FIXED
Product: GIMP
Classification: Other
Component: Tools
git master
Other All
: Normal normal
: 2.10
Assigned To: GIMP Bugs
GIMP Bugs
Depends on:
Blocks:
 
 
Reported: 2016-06-29 18:56 UTC by jose americo gobbo
Modified: 2018-04-10 08:36 UTC
See Also:
GNOME target: ---
GNOME version: ---


Attachments
test made with 'Pen Generic' (paint dynamics) + '2. Hardness 100' (brush) (124.04 KB, image/png)
2016-06-29 18:56 UTC, jose americo gobbo
Details

Description jose americo gobbo 2016-06-29 18:56:06 UTC
Created attachment 330611 [details]
test made with 'Pen Generic' (paint dynamics) + '2. Hardness 100' (brush)

I have noted an interesting issue with descendents curves linear or not... when you lift quickly the stylus pen (graphical tablets) the in the end stroke is printed an additional stain with intermediate value (in the curve)... but if you lift it slowly GIMP receives a values near to zero... that is this case is mapped as maximum value in the curve.

I have tested with a default paint dynamics, 'Pen Generic' and I have used '2. Hardness 100' as brush.

I am not sure if is a bug or not, but, I think that this behavior is strange, because when the value is near to maximum (x,y) I understand as end of the curve and not necessarily as a cycle, ready to begin again.

I have noted, that it has minimum and maximum time connected on this behavior... if you wait a bit with max pressure, for instance (max x axis), the print of intermediate value not happens.

Is possible, to control this behavior via tool options or better via preferences?

In many circumstances, the inverted or parabolic curves (with maximum or intermediate values near to zero)  are used to emulate different painting tools or techniques... and this effect is very annoying.
Comment 1 jose americo gobbo 2016-06-29 19:30:12 UTC
Steps:
1) set 'Pen Generic' as Paint Dynamics
2) set '2. Hardness 100' as brush;
3) paint a stroke increasing the pressure... and stop the stroke painting but maintain  the pressure to max... and lift the stylus quickly;
4) paint a stroke increasing the pressure... and stop the stroke painting, maintain the pressure to max for some secs, and lift slowly the stylus pen.

In the major part of cases in 3) is printed a dab with value intermediate of curve.
In some cases of the 4) is possible to avoid the print of the dab with value intermediate.
Comment 2 jose americo gobbo 2018-04-04 00:08:51 UTC
On GIMP 2.10 rc1, last updated the issue it seems fixed!