Subject: Re: [linux-audio-dev] Plugin GUIs
From: Paul Davis (pbd_AT_op.net)
Date: Sat Mar 24 2001 - 14:36:18 EET
>Storing multiple frames for knobs etc. is best done as a strip or grid
well, yes and no. in X, when you use draw a pixmap on the screen
(where a pixmap is just a "pixel map"), you specify both the
coordinates to draw *at* within the window and the offset and size
*within* the pixmap itself. This means that the pixmap can be large,
but you choose to just draw some part of it. there's a funky little
linux tb303 emulator called gsyn that used this approach for its
knobs. so you certainly can use a strip but ... the theoretical
benefit of it being does as a strip probably has do with memory
issues. but remember: we're running X, and the pixmaps are server
side, so we really have no notion of how they're laid out in the
server's memory. i'm not aware of any hints that its more efficient
with X to use N pixmaps version N sections of 1 pixmap. windows (and
macos) have a very different drawing API when it comes to bit/pixmaps,
and this may cause more of a preference for strips.
>(Multibit) alpha is important
debatable. it certainly makes it look nicer, but i don't know if the
difference is that important. i think that chrome is nice, but
polished chrome may be unnecessary :)
>Using a 3d rendered model to get the basic shape is good, then touch up with
>photoshop.
in linux-speak: start with POVray, then use the GIMP. this is
definitely a nice idea. the GIMP has a really cool animation plugin
that makes generation, say, 32 rotated knob images totally a breeze.
>I've probably missed some points, but that was what I picked up on. I
>asked him what he though of using XML to represent the layout, and he though
>it wasa good idea, but he expected we would compile into something more
>effient before distributing. Not sure that is a good idea myself.
its not a good idea. it takes less time to convert the XML into
"something more efficient" than it does to move the mouse to tweak a
knob. why would we want to give up an easy-to-read, easy-to-parse
format for the sake of a couple of hundred milliseconds ?
>Doesn't alpha blending really sting X servers, even with Xrender? I
i'm not sure there's been any general verdict on this yet. i suspect
it depends strongly on the video h/w involved and the quality of the
driver implementation.
>3D rendering is kinda obvious really. A guy at work is a bit of a wizz
>with blender, so I might ask him for a quick lesson, or at least borrow
though you can get very similar effects with the GIMP, using a bump
map and lighting effects.
--p
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