Unknown Geometry Manager

Unknown Geometry Manager
←	Chapter 11. Custom Jeszra	→

Jeszra supports over 15 geometry managers. Still, it could happen, that a needed geometry manager isn't yet integrated.

Jeszra uses a series of generic methods to create code for an unknown geometry manager. If the unknown geometry manager conforms to the interface of »grid«, »pack«, »place«, »table« (BLT), »tixform«: All that is needed is to teach Jeszra the new geometry manager is to use the meta geometry code creation. This is done through the preference variable ::rat(settings,Code,Meta,Geometry) .

Example 11.4. Include an Unknown Manager

Execute the following command in the shell, before the code generation:

lappend ::rat(settings,Code,Meta,Geometry) \
        »unknown manager«

Other, non-standard geometry managers cannot be supported this way. The code generation must be extended to include unconventional geometry managers.

Example 11.5. Code generation for Pack

Inside vg26/library/vgcode.tcl:

proc vgcode::dump-geometry-pack {
  target ta_name
  basename id_base
  ch_class {class ""}
  } {
 
   # calls the meta-code generation:
   set out [vgcode::dump-geometry-meta \
               $target $ta_name $basename \
               $id_base $ch_class pack];

    # Deals with propagation:
    if ![pack propagate $target] {
        append out [dumper::propagate \
                       pack $ta_name 0]
    }

    return $out;
}

Example 11.6. ...Code generation for Pack

... and inside vg26/library/tcldumper.tcl:

proc dumper::metamanager {
    manager window container properties
    } {
    return [subst \
{
    # Geometry for '$container' child window.
[format {%20s %s} $manager $window ] $properties
}]
}

Example 11.5, “Code generation for Pack” shows the procedures, most important for the »pack« geometry manager. Code generation can be ensured, for an unknown manager, by implementing a similar procedure pair for it. The procedure must follow the given naming convention. vgcode::dump-geometry-zincwindow for example, generates code for windows embedded in a TkZinc 3.3.4 window.

Built-in geometry managers are always unconventional. The default for built-in managers is the Tk canvas window. The built-in code from the palette entry is being used, as a last resort for code generation.

In both cases, the possible interactions with unknown managers is extremely limited.

←	↖	→
Preferences	↑	Customize Palettes