View source for Dev:Adding a Sound notification

After the implementation of [https://github.com/synfig/synfig/issues/648| #648 - GUI: Play a sound when rendering is done], it could be useful to keep a track of the way to implement a new sound notification in SynfigStudio

This tutorial will be divided in 2 parts:
* Adding the sound notification
* Adding an option to Preferences dialog

== Adding the sound notification ==

=== synfig-studio/sounds/ ===
* Add your sample in this directory in your source tree<br />
* Add a notice about the license of your sample in ''readme.txt'' (the asset should have a permissive license)<br />
* Add your sound sample to the list in ''Makefile.am''

=== synfig-studio/src/gui/app.h ===
* Declare the sound (Mix_Chunk*) as a static member.
 //The sound effects that will be used
 static Mix_Chunk* gRenderDone;

''You could add a bool declared as a static member for an option to play the sound (to be defined in Preferences dialog).''
 static bool use_render_done_sound;

=== synfig-studio/src/gui/app.cpp ===
* Initialize the sound (Mix_Chunk*) to NULL.<br />
You could find the gRenderDone and add it after. 
 Mix_Chunk* App::gRenderDone = NULL;

''As well you may initialize the bool for allow to play the sound; this will be connected later in the Preferences dialog''
 bool App::use_render_done_sound = true;
* Locate this part (at the end of the constructor App::App )
 path_to_sounds += ETL_DIRECTORY_SEPARATOR;
and load your sound as follow (the volume is set at 50% if success)
 //Load sound effects
 App::gRenderDone = Mix_LoadWAV( (path_to_sounds + "renderdone.wav").c_str() );
 if ( App::gRenderDone == NULL ) {
     synfig::error( _("SDL_mixer could not load gRenderDone : %s\n"), Mix_GetError() );
 }  else {
     Mix_VolumeChunk(App::gRenderDone, MIX_MAX_VOLUME/2);
 }
* Finally, free the sound in the destructor App::~App(and NULL the pointer)
 //<!- ----- SDL2 - Sound effects -----
 //Free the sound effects
 Mix_FreeChunk( App::gRenderDone );
 App::gRenderDone = NULL;

=== synfig-studio/src/gui/<yourSource>.cpp ===
* You should add
 #include <SDL2/SDL.h>
 #include <SDL2/SDL_mixer.h>
* Add your sound effect play where it should be (end of an event for example)<br />
You have 2 possibilities after this<br />
1) Play directly without control in the preferences
 //Sound effect - RenderDone (-1 : play on first free channel, 0 : no repeat)
 Mix_PlayChannel( -1, App::gRenderDone, 0 );
'''or'''<br />
2) ''Play according the preferences''
 //Sound effect - RenderDone (-1 : play on first free channel, 0 : no repeat)
 if (App::use_render_done_sound) Mix_PlayChannel( -1, App::gRenderDone, 0 );
== Adding an option to Preferences dialog ==
In the first part we added ''use_render_done_sound'' to prepare a preference option.<br />
It will be a toggle ''toggle_play_sound_on_render_done'' in Preferences/Render tab
=== synfig-studio/src/gui/dialogs/dialog_setup.h ===
* In class Dialog_Setup<br />
add the declaration of the "changed" handler
 void on_play_sound_on_render_done_changed();
and the corresponding Switch control
 Gtk::Switch toggle_play_sound_on_render_done;
=== synfig-studio/src/gui/dialogs/dialog_setup.cpp ===
* Find in which page and which position you will add your option (named ''toggle_play_sound_on_render_done'', here in ''Dialog_Setup::create_render_page(PageInfo pi)'')
 // Render - Render Done sound
 attach_label(pi.grid, _("Chime on render done"), ++row);
 pi.grid->attach(toggle_play_sound_on_render_done, 1, row, 1, 1);
 toggle_play_sound_on_render_done.set_halign(Gtk::ALIGN_START);
 toggle_play_sound_on_render_done.set_hexpand(false);
 toggle_play_sound_on_render_done.set_tooltip_text(_("A chime is played when render has finished."));
 toggle_play_sound_on_render_done.property_active()
                                 .signal_changed()
                                 .connect(sigc::mem_fun(*this, &Dialog_Setup::on_play_sound_on_render_done_changed));
* In ''Dialog_Setup::on_apply_pressed()''
 // Set the use of a render done sound
 App::use_render_done_sound = toggle_play_sound_on_render_done.get_active();
* Create the handler
 void
 Dialog_Setup::on_play_sound_on_render_done_changed()
 {
     App::use_render_done_sound = toggle_play_sound_on_render_done.get_active();
 }
* In ''Dialog_Setup::refresh()''
 // Refresh the status of the render done sound flag
 toggle_play_sound_on_render_done.set_active(App::use_render_done_sound);
=== synfig-studio/src/gui/app.cpp ===
* In ''class Preferences'',
among the saving parts
 if(key=="use_render_done_sound")
 {
     value=strprintf("%i",(int)App::use_render_done_sound);
     return true;
 }
and among the loading parts
 if(key=="use_render_done_sound")
 {
      int i(atoi(value.c_str()));
      App::use_render_done_sound=i;
      return true;
 }
* In the ret.push_back part, add
 ret.push_back("use_render_done_sound");
* In ''restore_default_settings()'', add a default value
 synfigapp::Main::settings().set_value("use_render_done_sound", "1");


Dont forget some parts have been done in the first section<br />
Hoping it will be sufficient to understand the whole system :)