more docs for the state of dparams

Original commit message from CVS:
more docs for the state of dparams
This commit is contained in:
Stefan Kost 2005-02-22 13:44:28 +00:00
parent 8a8871ee2d
commit 43a01f1a67
7 changed files with 76 additions and 7 deletions

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@ -1,3 +1,13 @@
2005-02-22 Stefan Kost <ensonic@users.sf.net>
* docs/libs/tmpl/gstcontrol.sgml:
* docs/libs/tmpl/gstdparam.sgml:
* docs/libs/tmpl/gstdplinint.sgml:
* docs/libs/tmpl/gstdpman.sgml:
* docs/libs/tmpl/gstdpsmooth.sgml:
* docs/libs/tmpl/gstunitconvert.sgml:
more docs for the state of dparams
2005-02-19 Benjamin Otte <in7y118@public.uni-hamburg.de>
* gst/gstelementfactory.c: (gst_element_factory_create):

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@ -6,15 +6,25 @@ dynamic parameter functionality.
<!-- ##### SECTION Long_Description ##### -->
<para>
This library provides a Manager that maintains a list of dynamically
controlable parameters for a GstElement.
This library provides a manager component (#GstDParamManager) that maintains a
list of dynamically controlable parameters for a #GstElement.
Just think of a volume slider in a mixer.
</para>
<para>
To use this library one needs to add some code to initialize it.
#GstElement instances wanting to provide dynamic parameters, need to provide
a #GParamSpec and an update method. The application that will later use the
control parameter, will create a #DParam instance and attach that to use
provided #GParamSpec and update method.
The control library provides several #DParam implementations that can be used
interchangably. The base on just updated the parameter, while others can smooth
the control changes.
</para>
<para>
To use this library in a application one needs to add some code to initialize it.
<example>
<title>Adding the control library to a project</title>
<title>Adding the control library to an application (step 1)</title>
<programlisting>
...
&hash;include &lt;gst/gst.h&gt;
@ -25,7 +35,37 @@ gst_control_init(&amp;argc,&amp;argv);
...
</programlisting>
</example>
The next step is to get hold of the GstDParamManager instance of a GstElement.
</para>
<para>
The next step is to get hold of the #GstDParamManager instance of a #GstElement
and set the working mode of the manager.
<example>
<title>Adding the control library to an application (step 2)</title>
<programlisting>
dparam_manager=gst_dpman_get_manager(element);
gst_dpman_set_mode(dparam_manager, "synchronous");
</programlisting>
</example>
</para>
<para>
Finally one need to attach a new #DParam to the paramter spec.
<example>
<title>Adding the control library to an application (step 3)</title>
<programlisting>
pspec=gst_dpman_get_param_spec(dparam_manager,"volume");
dparam=gst_dparam_new(G_PARAM_SPEC_VALUE_TYPE(pspec));
gst_dpman_attach_dparam(dparam_manager,g_param_spec_get_name(pspecs),dparam);
</programlisting>
</example>
For a full example look at the <file>gst-plugins/gst/sine/demo-dparams.c</file>
</para>
<para>
To add dparam support to a plugin look at <file>gst-plugins/gst/sine/gstsinesrc.c</file>
or <file>gst-plugins/gst/volume/gstvolume.c</file>.
The key concept is to call GST_DPMAN_PREPROCESS() before processing data and to
wrap the data processing (chain or loop function) by GST_DPMAN_PROCESS().
This allows the manager to interupt processing to apply new control values.
</para>
<!-- ##### SECTION See_Also ##### -->
@ -33,6 +73,9 @@ The next step is to get hold of the GstDParamManager instance of a GstElement.
</para>
<!-- ##### SECTION Stability_Level ##### -->
<!-- ##### FUNCTION gst_control_init ##### -->
<para>

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@ -27,6 +27,9 @@ network connections also need a protocol to do this.
#GstBuffer, #GstCaps, #GstEvent
</para>
<!-- ##### SECTION Stability_Level ##### -->
<!-- ##### ENUM GstDPHeaderFlag ##### -->
<para>

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@ -6,7 +6,8 @@ dynamic parameter instance
<!-- ##### SECTION Long_Description ##### -->
<para>
This base class for dynamic parameters will update parameters as they are.
Subclasses of this do more advanced updates like smoothing parameter changes.
</para>
<!-- ##### SECTION See_Also ##### -->
@ -14,6 +15,9 @@ dynamic parameter instance
</para>
<!-- ##### SECTION Stability_Level ##### -->
<!-- ##### STRUCT GstDParam ##### -->
<para>

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@ -14,6 +14,9 @@ linear interpolation dynamic parameter
</para>
<!-- ##### SECTION Stability_Level ##### -->
<!-- ##### STRUCT GstDParamLinInterp ##### -->
<para>

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@ -6,7 +6,7 @@ dynamic parameter manager
<!-- ##### SECTION Long_Description ##### -->
<para>
The manager bings all functions to work with #GstElements and their #GstDParams.
The manager provides a set of functions to work with #GstElements and their #GstDParams.
One can find out which dparams an element has, get the parameter specs and
pick a control change rate.
</para>
@ -20,6 +20,9 @@ are for applications that use elements with dparams.
</para>
<!-- ##### SECTION Stability_Level ##### -->
<!-- ##### STRUCT GstDParamManager ##### -->
<para>

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@ -14,6 +14,9 @@ realtime smoothed dynamic parameter
</para>
<!-- ##### SECTION Stability_Level ##### -->
<!-- ##### STRUCT GstDParamSmooth ##### -->
<para>