Position of Forms on the Screen

Mostly forms are automatically positioned by the system according to their type and the way they are shown.

The origin of a form is its top left hand corner.

When a form is displayed as a child form then it is always positioned with respect to its parent.

For a form shown from a MENU, its origin is at the origin of the parent. If the form is displayed from a BUTTON or any other gadget, its origin is at the center of the gadget.

When a form is shown as a free form for the first time then its default position is at the top left-hand corner of the screen.

We strongly recommend that you allow the system to position forms whenever possible.

• Use the following commands or methods to force the screen position of free-standing forms:

  show !!MyForm Free At xr 0.3 yr 0.5

  show !!MyForm Free centered xr 0.5 yr 0.5

  !!MyForm.show( 'At', 0.3, 0.5 )

  !!MyForm.show( 'Cen', 0.5, 0.5 )

The At option puts the origin of the form at the specified position; alternatively the Cen option puts the centre of the form at the given position. The co-ordinate values are fractions of the screen width or height respectively and are referred to as screen co-ordinates.

For example:

show !!MyForm free At xr 0.25 yr 0.1

positions the origin of !!MyForm one quarter of the way across from the left edge of the screen, and one tenth of the way down from the top.

!!MyForm.show( 'Cen', 0.5, 0.5 )

centres !!MyForm at the middle of the screen.