Implementation Notes

Implementation hints.

Collaboration diagram for Implementation Notes:

Implementation hints.

The dialog framework is part of the GWEN_GUI framework (Graphical User Interface). To make your implementation available to the application you will have to set the following callbacks in GWEN_GUI:

• GWEN_Gui_ExecDialog (use GWEN_Gui_SetExecDialogFn)
• GWEN_Gui_OpenDialog (use GWEN_Gui_SetOpenDialogFn)
• GWEN_Gui_CloseDialog (use GWEN_Gui_SetCloseDialogFn)
• GWEN_Gui_RunDialog (use GWEN_Gui_SetRunDialogFn)

The function GWEN_Gui_ExecDialog can be implemented by just calling the other functions (first GWEN_Gui_OpenDialog followed by GWEN_Gui_RunDialog and GWEN_Gui_CloseDialog).

Your implementation of GWEN_Gui_OpenDialog must set the follwing callbacks in the object pointed to by the first argument (GWEN_DIALOG):

• GWEN_Dialog_SetIntProperty (use GWEN_Dialog_SetSetIntPropertyFn)
• GWEN_Dialog_GetIntProperty (use GWEN_Dialog_SetGetIntPropertyFn)
• GWEN_Dialog_SetCharProperty (use GWEN_Dialog_SetSetCharPropertyFn)
• GWEN_Dialog_GetCharProperty (use GWEN_Dialog_SetGetCharPropertyFn)

The GKT2 implementation does it like this:

GWEN_INHERIT(GWEN_DIALOG, GTK2_GUI_DIALOG)
 
void Gtk2Gui_Dialog_Extend(GWEN_DIALOG *dlg) {
  GTK2_GUI_DIALOG *xdlg;
 
  GWEN_NEW_OBJECT(GTK2_GUI_DIALOG, xdlg);
  GWEN_INHERIT_SETDATA(GWEN_DIALOG, GTK2_GUI_DIALOG, dlg, xdlg, Gtk2Gui_Dialog_FreeData);
 
  GWEN_Dialog_SetSetIntPropertyFn(dlg, Gtk2Gui_Dialog_SetIntProperty);
  GWEN_Dialog_SetGetIntPropertyFn(dlg, Gtk2Gui_Dialog_GetIntProperty);
  GWEN_Dialog_SetSetCharPropertyFn(dlg, Gtk2Gui_Dialog_SetCharProperty);
  GWEN_Dialog_SetGetCharPropertyFn(dlg, Gtk2Gui_Dialog_GetCharProperty);
}

It must also create the actual widgets used by your GUI toolkit (e.g. QLabel for label widgets with QT). To do that you should call GWEN_Dialog_GetWidgets to get the tree of widget descriptions. The most important information about a widget is its type (GWEN_Widget_GetType). The implementation of GWEN_Gui_OpenDialog can use that information to decide what GUI widget should be created to represent that widget description.

For example the QT implementation creates a QLabel object for the widget type GWEN_Widget_TypeLabel.

You can call the function GWEN_Widget_SetImplData to store a pointer to the GUI widget created (e.g. the QT implementation stores a pointer to the created QLabel object for widgets of type GWEN_Widget_TypeLabel). To retrieve that pointer later call GWEN_Widget_GetImplData. Currently up to 4 pointers can be stored per GWEN_WIDGET object (in the case that there are multiple GUI objects required to represent a given GWEN_WIDGET).

Another important hint comes from the widget flags (get them with GWEN_Widget_GetFlags). Those flag tell the implementation about some layout options and other things.

For widgets using media like icons or images the implementation can call GWEN_Dialog_GetMediaPaths to get a list of paths where those icons can be found. This information is provided by the dialog itself. You can use functions like GWEN_Directory_FindFileInPaths to actually find the icon or image file using the media paths.

This example shows how the GTK2 implementation creates a GUI representation of type GWEN_Widget_TypeLabel:

#define GTK2_DIALOG_WIDGET_REAL    0
#define GTK2_DIALOG_WIDGET_CONTENT 1
 
int Gtk2Gui_WLabel_Setup(GWEN_WIDGET *w) {
  GtkWidget *g;
  const char *s;
  uint32_t flags;
  GWEN_WIDGET *wParent;
 
  flags=GWEN_Widget_GetFlags(w);
  wParent=GWEN_Widget_Tree_GetParent(w);
  s=GWEN_Widget_GetText(w, 0);
 
  g=gtk_label_new(s);
  GWEN_Widget_SetImplData(w, GTK2_DIALOG_WIDGET_REAL, (void*) g);
  GWEN_Widget_SetImplData(w, GTK2_DIALOG_WIDGET_CONTENT, (void*) g);
 
  GWEN_Widget_SetSetIntPropertyFn(w, Gtk2Gui_WLabel_SetIntProperty);
  GWEN_Widget_SetGetIntPropertyFn(w, Gtk2Gui_WLabel_GetIntProperty);
  GWEN_Widget_SetSetCharPropertyFn(w, Gtk2Gui_WLabel_SetCharProperty);
  GWEN_Widget_SetGetCharPropertyFn(w, Gtk2Gui_WLabel_GetCharProperty);
 
  if (wParent)
    GWEN_Widget_AddChildGuiWidget(wParent, w);
 
  return 0;
}