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Bug 770978 - Paint Dynamics and Velocity parameter Graphs inconsistent with behaviors - Inverted
Paint Dynamics and Velocity parameter Graphs inconsistent with behaviors - In...
Status: RESOLVED OBSOLETE
Product: GIMP
Classification: Other
Component: General
git master
Other Linux
: Normal enhancement
: ---
Assigned To: GIMP Bugs
GIMP Bugs
Depends on:
Blocks:
 
 
Reported: 2016-09-07 00:36 UTC by jose americo gobbo
Modified: 2018-05-24 16:52 UTC
See Also:
GNOME target: ---
GNOME version: ---


Attachments
Graphical Proposal to show the increase orientation of graph axes (21.87 KB, image/jpeg)
2016-09-08 14:30 UTC, jose americo gobbo
Details

Description jose americo gobbo 2016-09-07 00:36:13 UTC
The graph of Velocity parameter versus Opacity, Size, Angle(*), Rate(*), Flow and Jitter are inverted.
The graph show xy(0,0) to xy(1,1), linear and crescent. When I increase the velocity Opacity, Size, Flow and Jitter are decreasing instead to increase.
The Angle and Rate is not possible verify easily... I need to think a manner to test effectively these two parameters, but apparently do not working correctly too.

Possible related bugs are:
1) Spacing on Paint Dynamics is inverted on graph and not is working with Spacing value of Tool Options > https://bugzilla.gnome.org/show_bug.cgi?id=768118
2) Paint Dynamics and Inverted curves - print strokes with value intermediate to value equal zero > https://bugzilla.gnome.org/show_bug.cgi?id=768206
Comment 1 Massimo 2016-09-07 10:20:54 UTC
(In reply to jose americo gobbo from comment #0)
> The graph of Velocity parameter versus Opacity, Size, Angle(*), Rate(*),
> Flow and Jitter are inverted.
> The graph show xy(0,0) to xy(1,1), linear and crescent. When I increase the
> velocity Opacity, Size, Flow and Jitter are decreasing instead to increase.
...

Disclaimer: I did not contribute the code and I'm not a digital
painter.

If you're talking of the default (curve) behaviour,
I'd say it makes sense. That is if you increase the
velocity the same ink/flow is spread over a longer
length and so its effect/intensity is locally decreased.

If the curves have been chosen to model this behaviour
I think it is kind of intuitive (I've never read the
docs about it).

OTOH unless the behaviour changed as a consequence of
code refactoring/cleanup/bug fix, it is hard to invert 
the meaning of these curves today because custom dynamics 
would suddenly behave inversely to their original design
Comment 2 Michael Schumacher 2016-09-07 13:01:44 UTC
I'm pretty sure the current behavior for the features described in this bug is intentional.
Comment 3 jose americo gobbo 2016-09-07 17:31:54 UTC
Is reasonable the explanations and motivations... but, is an also, the wrong representation of this behavior in the graph.
In praxis, the user must in this case, create a wrong graph to have the correct output.
Comment 4 jose americo gobbo 2016-09-08 14:30:42 UTC
Created attachment 335118 [details]
Graphical Proposal to show the increase orientation of graph axes

I think very interesting to have the possibility, in future, the print values 'min and max' directly on the axes.

But could be useful also to have another approach, more graphical... I have thought in two ways to resolve the inversion of the growing in the axes:

1) Small bar of the side each axis representing the growing sense. 
2) Create a simplified gradient to indicate where is the max and the min.

The first option could be more useful. But, have the gradients is more fine, and the growing is showed in a way more simplified and effective.
When the 'min' and 'max' will be printed on the axes, the simplified gradient option (2), can help the user to confirm the effective behavior of each graph.

Some time ago, I have also write on bugzilla, an enhancement proposal to compact the paint dynamics dialogues, and I suppose that has relation with my initial proposal, you can read in:

https://bugzilla.gnome.org/show_bug.cgi?id=768259
Comment 5 GNOME Infrastructure Team 2018-05-24 16:52:32 UTC
-- GitLab Migration Automatic Message --

This bug has been migrated to GNOME's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.gnome.org/GNOME/gimp/issues/958.