Dev:Adding a Render progress bar

Now let's implement a Render Progress Bar!
It has been requested several time:
Indication needed that rendering is in progress. #383
Feature request: Give feedback when rendering is happening and complete #626
also in Default render parameter are bad #464

Things to take into account

• Where to place the Progress Bar?
  
• How does really a render work?
  
• Where to do calls and implementation?
  

Where to place the Progress Bar?

I chose to implement it in the Dock_Info panel.
After all, this is a kind of information!

Implementation

synfig-studio/src/gui/docks/dock_info.h

• Declare the components and members
  

In #include section

#include <gtkmm/progressbar.h>

In private section

Gtk::ProgressBar render_progress;

//! Number of passes request - 1 or 2 (if alpha)
int              n_passes_requested;
//! Number of passes pending - 2,1,0
int              n_passes_pending;

In public section

//! Current render progress - 0.0 to 1.0
//  depends on n_passes_requested and current_pass
void set_render_progress   (float value);
void set_n_passes_requested(int   value);
void set_n_passes_pending  (int   value);