Re: [Gimp-user] How to draw with pressure dependend brush size

[Jehan Pagès <jehan marmottard gmail com>]

Hi,

On Wed, Sep 19, 2012 at 4:02 AM, scl <scl gplus gmail com> wrote:
> Hi,
>
> there was a question in Bugzilla [1] that is better discussed here.
>
> Problem: A user wants to draw with the pencil or the ink tool using a
> tablet. The brush size should increase with the pressure: low pressure
> should result in a small brush size, high pressure result in a bigger brush
> size.
>
> Solution:
> 1. Make sure GIMP recognizes tablet pressure. You find some useful
> information in the thread [2] a few days ago, especially the posting of
> Jehan Pagès (thanks Jehan ;-) ).

No prob. I know this is quite a typical problem that a lot of people
encounters (cf. all the forums, blog posts, etc. where people
encoutered this ). I even think that this configuration of tablet
should be a default (then power-users may change the settings later,
but at least one-time users have a good experience with a suitable
tablet pressure).

I am actually not a graphist myself, rather a developer, but I am
currently working with one, and we are trying to get to a full
free-software stack. I will probably make a blog post later to details
all the process and all the tricks I learned from various people. :-)

> 2. in the Windows menu select 'Dockable Dialogs', then 'Paint Dynamics'. The
> 'Paint dynamics' dockable will open.
> 3. In the 'Paint dynamics' dockable list select 'Negative size pressure'.
> Right click on it, select 'Duplicate dynamics'. A copy of this dynamics will
> be created and opened in the 'Paint Dynamics Editor' dockable.
> 4. In the 'Paint Dynamics Editor' there's a textbox for the name of the
> Dynamics at the top. Enter a meaningful name, like 'Positive size pressure'.
> 5. Below that textbox is a listbox at the top. Choose 'Size'. This will show
> a diagram, showing the effect of the pressure on the brush size. Drag the
> ends of the descending red line to match the ascending gray line.

I don't really understand here. Seems like very close to "Pencil
Generic" which is the default dynamics, isn't it? I mean, "Pencil
Generic" has a slightly different curve (not straight proportional),
but opacity also increases with pressure, as well as size.

I don't say this new dynamics is worst or better. I guess only a
graphist having to use it daily could say which one feels nicer/more
realistic/comfortable. I simply don't understand why you seem to say
that this is *completely* different from the current default:
> The brush size should increase with the pressure: low pressure
> should result in a small brush size, high pressure result in a bigger brush
> size.
For me this is exactly what I got by defaults with "Pencil Generic".
Maybe there is something I did not understand in your new dynamics?

> 6. Save the settings for this Paint Dynamics.
> 7. In the Paint tool (Pencil, Paintbrush, Airbrush, etc). choose your new
> Paint Dynamics and start painting.

About this, I have a comment. I think graphists don't see it because
they (you?) do everything with their tablet. But as I was using the
mouse to change the pen features, then trying to draw with the pen, I
had a hard time figuring out why my settings were never applied to my
drawing.
Then I understood that Gimp actually records separate features for
each pen/tablet/mouse. So if you choose a tool, a brush, and customize
it with your mouse, then choose another tool, brush, other
customization with your tablet pen, you can use both of them by just
switching mouse and pen without touching the menu.
Even better: if you plug 2 tablets, you can use different tools on
each (actually tested and working!).
What I would love to test is 2 pens for the same tablet: will Gimp
make the difference and record different settings for each pen (we
have 2 tablets, but unfortunately pens on each are not compatible, so
I can't test)? That would be awesome.

I know you can easily switch tools with shortcuts and save and load
tool settings (though I have not found if there was a way to assign
shortcuts to a specific settings, let's say one you often switch to.
If someone has a hint...), so maybe it is not that helpful. But maybe
being able to replace these by switching pens physically, more like a
common non-digital workflow, may be interesting as well for some
people (I guess).

Thanks!

Jehan

> I hope this helps.
> BTW is there a need to ship these Paint dynamics settings with GIMP?
>
> Kind regards,
>
> Sven
>
> [1] https://bugzilla.gnome.org/show_bug.cgi?id=682351
> [2]
> https://mail.gnome.org/archives/gimp-user-list/2012-September/msg00212.html
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