[LAD] [ANN] lv2-c++-tools 1.0.0

Lars Luthman lars.luthman at gmail.com
Thu Apr 17 11:26:08 UTC 2008

On Thu, 2008-04-17 at 13:08 +0200, Pau Arumí wrote:
> > So basically it's just a more descriptive way of referencing plugin
> > ports. You could just as well use the indices and the number of ports
> > directly and don't bother with lv2peg, but it's nice to have while
> > working on a plugin with lots of ports where you may remove and add
> > ports while hacking, or change ranges and default values (those things
> > are also included in the output of lv2peg). There is more info and some
> > examples at http://lv2plug.in/lv2pftci/
> > 
> Now it all makes sense. Thanks.
> However I'd like to see the entire example (the link lv2pftci seems
> dead). If available, could you point to the generated gain.peg and the
> human written RDF? (Or an equivalent example)

Sorry, I got my addresses mixed up. The correct one is
http://ll-plugins.nongnu.org/lv2pftci .

For the example in the thread above the RDF would look something like

  @prefix lv2:  <http://lv2plug.in/ns/lv2core#>.
  @prefix doap: <http://usefulinc.com/ns/doap#>.
  @prefix ll: <http://ll-plugins.nongnu.org/lv2/namespace#>.
    a lv2:Plugin;
    lv2:binary <gain.so>;
    doap:name "Gain";
    doap:license <http://usefulinc.com/doap/licenses/gpl>;
    ll:pegName "p";
    lv2:port [
      a lv2:AudioPort, lv2:InputPort;
      lv2:index 0;
      lv2:symbol "in";
      lv2:name "Input";
      a lv2:AudioPort, lv2:OutputPort;
      lv2:index 1;
      lv2:symbol "out";
      lv2:name "Output";
      a lv2:ControlPort, lv2:OutputPort;
      lv2:index 2;
      lv2:symbol "gain";
      lv2:name "Gain";

...and lv2peg would output this:

  #ifndef gain_peg
  #define gain_peg
  #ifndef PEG_STRUCT
  #define PEG_STRUCT
  typedef struct {
    float min;
    float max;
    float default_value;
    char toggled;
    char integer;
    char logarithmic;
  } peg_data_t;
  /* <http://my.plugin/> */
  static const char p_uri[] = "http://my.plugin/";
  enum p_port_enum {
  static const peg_data_t p_ports[] = {
    { -3.40282e+38, 3.40282e+38, -3.40282e+38, 0, 0, 0 }, 
    { -3.40282e+38, 3.40282e+38, -3.40282e+38, 0, 0, 0 }, 
    { -3.40282e+38, 3.40282e+38, -3.40282e+38, 0, 0, 0 }, 

  #endif /* gain_peg */

Since no ranges or default values are given for the ports -FLT_MAX and
FLT_MAX are used, that's where the 3.40282e+38s come from.

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