GUI mixins

Classes
struct	LV2::NoUserResize< Required >
struct	LV2::FixedSize< Required >
struct	LV2::Presets< Required >
struct	LV2::WriteMIDI< Required >
struct	LV2::URIMap< Required >

Detailed Description

These classes implement extra functionality that you may want to have in your GUI class, just like the plugin mixins do for plugin classes. Some of them are template classes with a boolean Required parameter - if this is true the GUI will fail to instantiate unless the host supports the extension implemented by that mixin. For example, if you wanted a GUI that wrote a MIDI Note On event to port 3 in the plugin whenever the user clicked a button, you could do it like this:

#include <lv2gui.hpp>
#include <gtkmm.h>
 
class MyGUI : public LV2::GUI<MyGUI, LV2::URIMap<true>, LV2::WriteMIDI<true> > {
public:
  MyGUI(const char* plugin_uri)
    : m_button("Click me!") {
    pack_start(m_button);
    m_button.signal_clicked().connect(sigc::mem_fun(*this, &MyGUI::send_event));
  }
protected:
  void send_event() {
    uint8_t noteon[] = { 0x90, 0x50, 0x40 };
    write_midi(3, 3, noteon);
  }
  Gtk::Button m_button;
};

The function write_midi() is implemented in LV2::WriteMIDI and thus available in MyGUI. LV2::WriteMIDI requires that LV2::URIMap is also used (because of the way event types work in LV2) - if you don't add LV2::URIMap as well you will get a compilation error.