Convert Setup Form from FixChars to VarChars

Software Customisation Guide

Converting a Form to VarChars and Layout Form : Convert Setup Form from FixChars to VarChars

Many forms will convert satisfactorily by appending the VarChars keyword to the existing 'Setup form' command, but before performing any actual edits, the user can use the new FMSYS object method

!!FMSYS.SetDefaultFormLayout( mode is STRING )

to force the default layout mode for Setup form to 'VarChars'. Any existing forms they show after this setting will be using VarChars layout mode, so the user can see if they are satisfactory or not. There is also the method !!FMSYS.DefaultFormLayout( ) is STRING, so that the user can query the current default layout mode, in case they have forgotten.

The most notable effect of using VarChars is the reduction of size for gadgets that use literal text strings as part of their definition. This can upset the alignment of gadgets on an existing form when changing to VarChars.

Likely Causes of Problems

Assumptions in the PML code that the length of a string is (no.of characters x grid width).

Padding of gadget tag-text or gadget textual values with spaces to attempt alignment of a set of gadgets will not work with VarChars.

The reduction in size of a gadget that uses literal text can upset the positions or extents of gadgets that are aligned to them. For example: some uses of Path Down with Align Right may fail with the message "Attempt to place gadget off limits of form", because the gadget has been forced backward over the form edge.

Possible Solutions

The following is an armoury of techniques that can remedy conversion misalignments:

For gadget tag texts aligned by padding with spaces - remove the padding spaces, set a PML variable !wid = <desired width in grid units>, then use tagwid $!wid for each gadget that is to be aligned. The user can then experiment with different values of !wid until they get an acceptable result. The user can use the same $!wid value for the widths of other gadget types, e.g. button, toggle, radio-button etc. to align them with the gadget tags.

For other gadget text, e.g. a paragraph with literal text value, the user can force alignment of non-tag parts of gadgets to a common value e.g. wid $!wid, wid.<other_gadget_width>, wid to max.<other_gadget> or wid to min.<other_gadget>.

The new gadget Positional Extent syntax 'width to…' and 'height to…' will solve many alignment problems because it forces a gadget to extend from it's specified (or implied) starting co-ordinate to the max, min or centre of the target gadget.