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<H2><A NAME="sec:11.3"><SPAN class="sec-nr">11.3</SPAN> <SPAN class="sec-title">Dialog 
support libraries</SPAN></A></H2>

<A NAME="sec:libdia"></A>

<P>This section deals with a number of classes from the library to 
simplify the creation of dialog windows.

<H3><A NAME="sec:11.3.1"><SPAN class="sec-nr">11.3.1</SPAN> <SPAN class="sec-title">Reporting 
errors and warnings</SPAN></A></H3>

<P><A NAME="idx:messagesreporting:484"></A><A NAME="idx:errorsreporting:485"></A><A NAME="idx:reporting:486"></A>Error, 
and warning and informational messages are raised using the
<B><CODE>-&gt;</CODE>report</B> or <B><CODE>-&gt;</CODE>error</B> method 
defined on all <font size=-1>XPCE</font> objects. Basic error and 
message handling is described in <A class="sec" href="errors.html">section 
10.8</A>. The library
<CODE>library(pce_report)</CODE> defines the classes <B>reporter</B> and
<B>report_dialog</B>.

<P>
<UL>
<LI><I><B>reporter</B></I><BR>
This is a refinement of class <A class="" href="summary.html#class:label">label</A>, 
displayed using the fashionable lowered 3D-style. In addition, it 
redefines the <B><CODE>-&gt;</CODE>report</B> message to colour error 
messages red.

<P>
<LI><I><B>report_dialog</B></I><BR>
This is a trivial subclass of <A class="" href="summary.html#class:dialog">dialog</A>, 
displaying a
<B>reporter</B> and constraining this reporter to occupy the entire 
window.
</UL>

<P>An example using these classes is in <A class="sec" href="libdia.html">section 
11.3.2</A>.

<H3><A NAME="sec:11.3.2"><SPAN class="sec-nr">11.3.2</SPAN> <SPAN class="sec-title">Toolbar 
support</SPAN></A></H3>

<A NAME="sec:toolbar"></A>

<P><A NAME="idx:buttonbar:487"></A>The library <CODE>library(toolbar)</CODE> 
defines the classes <B>tool_bar</B>,
<B>tool_button</B> and <B>tool_status_button</B> to simplify the 
definition of tool-bars.

<DL>
<DT><STRONG>tool_bar -&gt;initialise:</STRONG> <VAR>Client:object*, 
Orientation:[{horizontal,vertical}]</VAR></DT>
<DD class="defbody">
Create a <B>tool_bar</B> for which the buttons execute actions on
<VAR>Client</VAR> (see class <B>tool_button</B> for details). By default 
the buttons are placed left-to-right, but using <CODE>vertical</CODE>
<VAR>Orientation</VAR> they can be stacked top-to-bottom.</DD>
<DT><STRONG>tool_bar -&gt;append:</STRONG> <VAR>Button:tool_button<TT>|</TT>{gap}</VAR></DT>
<DD class="defbody">
Append a tool-button to the bar or, using the name <CODE>gap</CODE>, 
make a small gap to separate logical groups of buttons.</DD>
<DT><STRONG>tool_bar -&gt;activate:</STRONG> <VAR></VAR></DT>
<DD class="defbody">
Send <B><CODE>-&gt;</CODE>activate</B> to all member buttons, reflecting 
whether they are ready to accept commands or `grayed-out'.</DD>
<DT><STRONG>tool_button -&gt;initialise:</STRONG> <VAR></VAR></DT>
<DD class="defbody">
Define a button for <A NAME="idx:toolbarsendappend:488"></A>`<B>tool_bar<CODE>-&gt;</CODE>append</B>'. <VAR>Action</VAR> 
is the action to execute. If this is a plain atom, this method without 
arguments is invoked on the <A NAME="idx:toolbargetclient:489"></A>`<B>tool_bar<CODE>&lt;-</CODE>client</B>'. 
If it is a code object this code is simply executed. <VAR>Label</VAR> is 
the label. Normally for toolbars this will be an <A class="" href="summary.html#class:image">image</A> 
object. <VAR>Balloon</VAR> defines the text for the popup-window if the 
user rests the pointer long enough on the button. It it is a name, this 
balloon is subject to
<A NAME="idx:namegetlabelname:490"></A>`<B>name<CODE>&lt;-</CODE>label_name</B>' 
(see <A class="sec" href="mlingual.html">section 11.7</A>), otherwise it 
is passed literally. Finally, if <VAR>Condition</VAR> is present it is 
evaluated by
<B><CODE>-&gt;</CODE>activate</B> to determine the activation-state of 
the button.</DD>
<DT><STRONG>tool_button -&gt;activate:</STRONG> <VAR></VAR></DT>
<DD class="defbody">
If <B><CODE>&lt;-</CODE>condition</B> is present, evaluate it and send <B><CODE>-&gt;</CODE>active</B>.</DD>
<DT><STRONG>tool_button -&gt;active:</STRONG> <VAR>Active:bool</VAR></DT>
<DD class="defbody">
If <A NAME="idx:off:491"></A><B>@off</B>, deactivate the button and 
provide visual feedback for this.
</DD>
</DL>

<P>A <B>tool_status_button</B> is toggled between depressed state and 
normal state on each click. If it has an atomic <B><CODE>&lt;-</CODE>action</B> 
it will send <VAR>action</VAR>: <A NAME="idx:on:492"></A><B>@on</B> to 
the client when going to depressed state and <VAR>action</VAR>:<A NAME="idx:off:493"></A><B>@off</B> 
when returning to normal state. If the <B><CODE>&lt;-</CODE>action</B> 
is a code object this boolean will for forwarded over the code object. 
See <A class="sec" href="exeobjects.html">section 10.2</A>.

<H3><A NAME="sec:11.3.3"><SPAN class="sec-nr">11.3.3</SPAN> <SPAN class="sec-title">Example</SPAN></A></H3>

<P>The example below uses these classes as well as class <A class="" href="summary.html#class:menu_bar">menu_bar</A> 
to arrive at a typical modern application layout.

<P><A NAME="fig:libdia"></A>
<CENTER>
<IMG SRC="libdia.gif">
</CENTER>
<TABLE ALIGN=center WIDTH="75%"><TR><TD>
<B>Figure 20 : </B>Simple application framework</TABLE>

<PRE class="code">
%       Pull in the classes

:- pce_autoload(report_dialog, library(pce_report)).
:- pce_autoload(tool_bar, library(toolbar)).
:- pce_autoload(finder, library(find_file)).
:- pce_global(@finder, new(finder)).

%       Define icons as program resources

resource(printer,       image,  image('16x16/print.xpm')).
resource(floppy,        image,  image('16x16/save.xpm')).

%       Define the application as a subclass of frame.

:- pce_begin_class(myapp, frame,
                   "Frame representing the application").

initialise(MyApp) :-&gt;
        send_super(MyApp, initialise, 'My application'),
        send(MyApp, append, new(D, dialog)),
        send(D, pen, 0),
        send(D, gap, size(5, 5)),
        send(D, append, new(menu_bar)),
        send(D, append, new(tool_bar(MyApp))),
        send(MyApp, fill_menu_bar),
        send(MyApp, fill_tool_bar),
        send(new(W, myapp_workspace), below, D),
        send(new(report_dialog), below, W).

fill_menu_bar(F) :-&gt;
        get(F, member, dialog, D),
        get(D, member, menu_bar, MB),
        send_list(MB, append,
                  [ new(File, popup(file)),
                    new(_Edit, popup(edit))
                  ]),

        send_list(File, append,
                  [ menu_item(load,
                              message(F, load),
                              end_group := @on),
                    menu_item(print,
                              message(F, print))
                  ]).

fill_tool_bar(F) :-&gt;
        get(F, member, dialog, D),
        get(D, member, tool_bar, TB),
        send_list(TB, append,
                  [ tool_button(load,
                                resource(floppy),
                                load),
                    gap,                % skip a little
                    tool_button(print,
                                resource(printer),
                                print)
                  ]).
                                
print(MyApp) :-&gt;
        "Print the document"::
        send(MyApp, report, progress, 'Printing ...'),
        get(MyApp, member, myapp_workspace, WS),
        send(WS, print),
        send(MyApp, report, progress, done).

load(MyApp) :-&gt;
        "Ask a file and load it"::
        get(@finder, file, @on, myp, File),
        get(MyApp, member, myapp_workspace, WS),
        send(WS, load, File).

:- pce_end_class(myapp).


%       dummy class for the work-area of your application

:- pce_begin_class(myapp_workspace, window).

:- pce_end_class(myapp_workspace).</PRE>

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