Mastering Perl/Tk

The Perl/Tk IPADM Client, ipadm

The client’s primary duties are to build the human interface and establish a communications link to the server, ipadmd. In order to talk to the server, ipadm starts the helper, ipadmh, as a separate process. Then ipadm sends a message to the daemon requesting a list of subnet descriptions, which it uses to construct the hypertext interface shown in Figure 19-2. Each subnet description has tags and bindings that react to mouseclicks and subsequently display the subnet’s nodes, as shown in Figure 19-3.

The following sections explain all this in detail.

Creating the Hypertext User Interface

As Figure 19-2 shows, ipadm’s MainWindow is essentially a single, scrolled ROText widget listing all of ACME Rocket Supply’s subnets.

my $t = $MW->Scrolled('ROText', 
    qw/-width 80 -height 10 -relief ridge -scrollbars w/);

As the cursor passes over a subnet line, it becomes “hot,” is highlighted in green, and is able to respond to a button click. Clicking on a hot item opens a Toplevel “subnet editing” window, which we’ll see shortly. All these actions are controlled by text tags and bindings. First, we create and configure several tags:

$t->tagConfigure(qw/title -font/ => 'Helvetica 18 bold');
$t->tagConfigure(qw/subnet -lmargin1 .5c -lmargin2 1c -foreground blue/);
$t->tagConfigure(qw/hot -relief raised -borderwidth 1 -background green/);

The title tag is applied to the title line, giving it a nice, large font. The subnet tag is applied to each subnet line, and the ...