Dev:Adding a Sound notification

After the implementation of #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
  
• Add a notice about the license of your sample in readme.txt (the asset should have a permissive license)
  
• 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).

bool       App::use_render_done_sound = true;

synfig-studio/src/gui/app.cpp

• Initialize the sound (Mix_Chunk*) to NULL.
  

You could find the gRenderDone and add it after.

Mix_Chunk* App::gRenderDone           = NULL;

As well you may add a 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)
  

You have 2 possibilities after this
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
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 );