Subject: Re: [linux-audio-dev] Knobs / widget design
From: torbenh_AT_gmx.de
Date: Thu Jun 10 2004 - 17:22:46 EEST
On Wed, Jun 09, 2004 at 04:25:15PM -0700, Tim Hockin wrote:
> On Wed, Jun 09, 2004 at 11:56:59PM +0200, Arnold Krille wrote:
> > Still the question is: What toolkit to use for a
> > standard-LAD-Gui-elements-set? Or just define the graphics and the handling
> > and then let everyone implement it in his/her preferred toolkit? The last
> > would be my suggestion, and maybe I am volunteering to create on for Qt...
>
> Other way around? Define a graphics system so I can add my own
> knob-graphics, and you make them work.
>
ok... small history of my experience with knobs:
i used a gif animation for the galan knob.
seemed nice because i know the size and the number of frames.
dawback: only 1 transparancy bit.
knob looks ugly on black background.
now i moved the code to use png which has real alpha information.
put all frames in a row.
but i have to hardcode the size or the number of frames.
(dont remember what i hardcoded (perhaps both :( ) )
solution is a textfile describing the knob or one integer in the png.
Although it seems nicer to put this metadata into the png, i think i
prefer the textfile, because i want to read the png using gdk-pixbuf and
i dont know how to get the metadata from gdk-pixbuf.
The text file could also define some of the behaviour of the knob in
response to the mouse.
This would allow to make a single widget which can behave like a slider
or a knob. in fact it only displays an animation.
so what do we get ?
---------------------------
nFrames=100
behaviour=0
image=filename.png
--------------------------
with behaviour being
0 = knob
1 = slider
2 = 2D Control (??)
the image= could be omitted if we say the name of the textfile should be
filename.ladcontrol or something.
if we agree on something like this i can contribute the gtk2 part of this
very fast.
the gtk1 part needs some work because its still loading gifs
its a widget with a GtkAdjustment... so it can be exchanged on the fly
with a GtkSlider
dont know about the qt side of things but it should be quite easy to do.
please comment...
-- torben Hohn http://galan.sourceforge.net -- The graphical Audio language
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