Subject: Re: [linux-audio-dev] ladspa xml gui
From: Paul Barton-Davis (pbd_AT_Op.Net)
Date: Fri Dec 08 2000 - 02:41:33 EET
>pixmap is used. Most of the GUI elements would be specified by
>parameters only (size, fontas to use etc...), no pixmaps.
As you have seen, thats not the case in the proposed XML DTD. There is
certainly no *need* to use pixmaps in the XML gui spec at all, but its
certainly possible.
>Even end user can create/edit XML and change the interface. While we're
>at it, the definition of a plugin should probably specify default XML
>filename to use but it should work with any, or in other words, the XML
>is provided by host and plugin doesn't even know about it.
The first part of this is correct, and I think the proposal for now is
to add:
const char * const (*xml_gui_description)();
to the LADSPA header. a plugin can leave this NULL if there is no GUI
spec associated with it. the host may in turn ignore it completely, or
use it as it sees fit. But the XML *specification* is provided by the
plugin, while the XML->GUI *implementation* is provided by the host,
and yes, the plugin has nothing whatsoever to do with except perhaps
to provide some pixmaps if the host wants to use them.
> check the freeamp, I like their theme/skin concept. the freeamp
>provides cartain functionality which can be used in XML, like play,
>volume, playlist etc... each of these can be controlled by GUI element
>that is defined in XML - bitmaps to use, position within window (even
>the main window size/shape) etc...
We can't do this. The list of functionality is potentially boundless.
We bind GUI elements to LADSPA control (and possibly audio) ports, and
those elements then can be used to display and/or modify the values
associated with the ports.
I think that it would be useful to be
>able to define these without any specific bitmaps, just by parameters,
>leave it up to host how to draw them. The bitmaps can be specified
>though...
We leave it up the host to decide what to do entirely. The XML does
include the option to request the use of pixmaps for some
elements. The host may choose to ignore them.
> resize: if bitmap is used, it can be: tiled/trimmed as need or resized
>(or something else), the specific action should be one of the
>parameters.
You cannot tile a non-rectangular pixmap. You cannot resize a pixmap
in general without either (1) a huge computational cost and/or (2)
crappy looking results.
In general, the widgets will operate *precisely* the way that many GUI
widgets do when resized: the spacing between them will increase, but
the widget sizes will remain the same.
--p
This archive was generated by hypermail 2b28 : Fri Dec 08 2000 - 03:50:54 EET