What is it?

gtkform is a gtk+ container that resembles the Motif XmFormWidget behavior.  For every edge (side) of a widget, you can assign an attachment.  These attachments can be relative to the form or to another widget.  The attachments determine the layout behavior of the form when resizing occurs.

http://www.echo-sol.com/~steveg/gtkform/gtkform.tar.gz

• 7 Jul 2005 - Ron Yorston <rmy@tigress.co.uk>
  • Updated from java version for "lower_container_relative".
  • Added ATTACH_SELF.
  • Updated for GTK+ 2.x.
  • Test program

Create a gtkform widget, add children and set contraints.  After a widget is added to a form, you can assign the attachments with a call to gtk_form_constrain.  Every call to gtk_form_constrain looks like this

gtk_form_constrain (Form widget, Edge, Attachment , Target, Offset);

Parameter	Explanation
Form widget	Form widget that contains the children.
Edge	Edge of the Component. GTK_FORM_EDGE_TOP GTK_FORM_EDGE_LEFT GTK_FORM_EDGE_BOTTOM GTK_FORM_EDGE_RIGHT
Attachment	GTK_FORM_ATTACH_NONE GTK_FORM_ATTACH_FORM GTK_FORM_ATTACH_WIDGET GTK_FORM_ATTACH_OPPOSITE_WIDGET GTK_FORM_ATTACH_CENTER GTK_FORM_ATTACH_SELF
Target	For WIDGET, OPPOSITE_WIDGET or CENTER
Offset	Offset from the target or form side.

 

Attachment	Explanation
GTK_FORM_ATTACH_NONE	Edge does not have any constraint.
GTK_FORM_ATTACH_FORM	Edge is layed out Offset pixels from the side of the form.
GTK_FORM_ATTACH_WIDGET	Edge is layed out Offset pixels from Target .
GTK_FORM_ATTACH_OPPOSITE_WIDGET	Edge is layed out Offset pixels from the opposite side of Target.
GTK_FORM_ATTACH_CENTER	Component is centered with respect to Target .  If Target is GTK_FORM_NULL_WIDGET, then widget is centered on the form.  The Edge specified with this call only determines which direction to take the offset.  If Offset is zero, then either edge will have the same outcome.
GTK_FORM_ATTACH_SELF	Edge is positioned at the same relative position within the form, even if the form is resized.

Aside from the fact that gtkform does not implement all of the XmForm functionality, gtkform does have extended functionality beyond XmForm.  Unlike XmForm, gtkform will allow widgets to have contraints relative to each other as long as they are not truely circular.  In other words, widget A can be attached to the left of widget B and widget B can be attached to the bottom of widget A.  Similiarly, widget A can be attached to itself.  This can be used to specify a fixed width or height for a component.  Lastly, gtkform supports centering.

gtkform is written and maintained by Steve Green and is licensed under the LGPL.
Original source and documentation is locatated at  http://www.echo-sol.com/~steveg/gtkform