Re: [boost] Java style GUI in C++

18 Aug 2004

      John Torjo wrote:
...
Hi Reece,
Just a few thoughts:
...
I am currently designing a GUI framework in C++ (initially targeting the 
Windows platform) that uses a model similar to that which Java uses in
Take a deep breath if you want to make it cross-platform ;)
I think that's Windows work x 10 or so. Maybe more ;) ...
I was thinking about having a compatibility layer, e.g.:

namespace windows
{
   class window
   {
      public:
         inline handle_type create( const string_type title, ... );
         inline void set_size( long, long );
         // ...
   };
}

namespace linux{ class window{ ... }; }

Then engineer the library on top of that. This would simplify x-platform 
development... the problem is working out the right abstraction.
...
...
it's AWT and Swing libraries. Specifically:
[1] Being able to use constructors to create the windows/components. This 
means there is no need to explicitly call a Create method like in the MFC 
framework.
win32gui does that ;)
:) I am having a look at all the links to the various libraries, so it may 
take a while to process them all. (Thanks for everyone who compiled the 
links).
...
...
[2] The use of layout managers. I like the various layout managers in Java 
and how easy it is to construct complex GUI interfaces.
I like the idea of layout managers. Still, it seems (to me) in real-life 
they kind of fail. You'll always want that special case where you need to 
hide control X and show control Y, etc.
So why not have that ability in the framework? That is the reason I posted 
this, to get ideas. It should not be that difficult to be able to change the 
layouts at run-time... once the layout managers have been written, that is.
...
So far, I've created splitters on dialogs at design time (still beta ;)). 
If you use them correctly, you can specify a lot ot design time. Also, you 
can easily hide/show the left/right panes.
cool.
...
...
[3] The support for events via "listeners". This will most likely be 
geared towards key/mouse events and "action" events (e.g. when the user 
presses on a button).
I'm not a big fan of listeners. You need to do a lot of coding manually to 
set them, etc. I've implemented them totally different - using event 
handler classes.
My idea was something along the lines of:

class MouseEvent
{
   public:
      static const int                 LeftButton   = 0;
      static const int                 MiddleButton = 1;
      static const int                 RightButton  = 2;
   private:
      int                              button;
      unsigned int                     vkeys;
      win::api::point                  pt;
   public:
      inline                 MouseEvent( int, WPARAM, LPARAM );
};

MouseEvent::MouseEvent( int btn, WPARAM wp, LPARAM lp ):
   button( btn ),
   vkey(   wp ),
   pt(     lp )
{
}

class MouseListener
{
   public:
      virtual void                               mouseMove(              
const MouseEvent & );
      virtual void                               mouseButtonDown(        
const MouseEvent & );
      virtual void                               mouseButtonUp(          
const MouseEvent & );
      virtual void                               mouseButtonDoubleClick( 
const MouseEvent & );
   public:
      virtual               ~MouseButtonListener();
};

With a common listener interface for GUI object actions, e.g. pressing a 
mouse button, selecting an item in a listbox, editing text, etc.
...
...
At the moment, I have a basic working version that allows you to write the 
following:
int PASCAL WinMain( HINSTANCE, HINSTANCE, LPSTR, int sw )
{
  swing::JFrame frame( L"Swing JFrame!" );
  frame.setPane( new swing::JPanel());
  frame.setSize( 500, 500 );
  frame.show( sw );
MessageLoop msg;
  return( msg.Execute());
}
can you break the message loop?
That is, specify when a message loop should end (when a certain signal is 
received).
You can call ::PostQuitMessage( 0 ), but that is Windows specific. At the 
moment the message loop doesn't do anything fancy (accelerator/dialog box 
message processing), but it is on the list of things to work on.
...
...
This creates two windows: the main frame and a panel that is a child of 
that frame. The JFrame is created in the constructor, but is not displayed 
until show is called. Likewise, the JPanel is created inside its 
constructor and the JFrame.setPane method makes that window a child of the 
frame.
I would appreciate comments and ideas as to what people would like out of 
a GUI framework, especially one that will be multi-platform.
I'm all for it, but again, I think it's so much work...
But it will be fun! :D

Regards,
Reece

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Re: [boost] Java style GUI in C++

Reece Dunn