PM123 Visual plug-ins

Visual plug-ins must implement and export the functions defined in visual_plug.h.

     HWND DLLENTRY vis_init( PVISPLUGININIT initdata );
Visual plug-in's vis_init() routine gets called every time plug-in gets activated. The VISPLUGININIT structure contains the initialization data that PM123 passes to the plug-in.
     typedef struct {
       int           x, y, cx, cy;
        /* Location where the plug-in should create its window */
       HWND          hwnd;
        /* PM123's window handle */
       PPLUGIN_PROCS procs;
        /* Pointers to functions which plug-ins can utilize */
       int           id;
        /* Plug-in's ID (1-32) */
       char          *param;
        /* Parameters passed to the plug-in */
       HAB           hab;   
        /* PM123's anchor block handle */

     } VISPLUGININIT, *PVISPLUGININIT;
On return from the initialization function, the function should return the plug-in's window handle. The plug-in shouldn't not rely that initdata structure is pointing to the right location all the time, instead it should make its own copy of the structure.

If the plug-in creates a window, here's a window procedure you should base yours on:

     MRESULT EXPENTRY PlugWinProc( HWND hwnd, ULONG msg, MPARAM mp1, MPARAM mp2 )
     {
       switch (msg)
       {
         case DM_DRAGOVER:
         case DM_DROP:
         case 0x041f:
         case 0x041e:
         case WM_CONTEXTMENU:
         case WM_BUTTON2MOTIONSTART:
         case WM_BUTTON1MOTIONSTART:
           WinSendMsg( plug.hwnd, msg, mp1, mp2 );
           break;

         /* your stuff */

         default:
           return WinDefWindowProc( hwnd, msg, mp1, mp2 );
       }
     }
If you want to create a window inside PM123's window, use WinCreateWindow() in vis_init():
     WinRegisterClass( hab,
                       "ExamplePlugin",
                       PlugWinProc,
                       CS_SIZEREDRAW, 0 );

     hwndClient = WinCreateWindow( initdata->hwnd,
                                   "ExamplePlugin",
                                   "PM123 Example Visual Plug-in",
                                   WS_VISIBLE,
                                   initdata->x,
                                   initdata->y,
                                   initdata->cx,
                                   initdata->cy,
                                   initdata->hwnd,
                                   HWND_TOP,
                                   initdata->id,
                                   NULL,
                                   NULL );
     return hwndClient;
Visual plug-ins should deinitialize and destroy their windows and free allocated memory when receiving a
     int DLLENTRY plugin_deinit();