| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |
Arguments: graphical-stream &optional (stream-units-p t)
Returns the current top margin of a graphical-stream, measured from the top edge of the stream. The top-margin is initially zero, except as noted below. (setf top-margin) may be called to set the margin at any time.
If stream-units-p is true, as it is by default,
then the margin is measured in pixels. If nil
, it is measured in text line heights (see line-height).
Margin attributes are provided primarily to allow an application to keep a drawing within arbitrary margins by drawing everything within the coordinates returned by left-margin, top-margin, right-margin, and bottom-margin. Common Graphics also uses them in a few special ways, though, as described below.
When opening a printer
stream or calling new-page to advance to
the next printed page, the current-position-x of the stream is
set to its left-margin, and the current-position-y is set
to its top-margin.
A printer
stream's coordinate system has position (0, 0) at the printer-physical-offset
of the printer. To allow an application to avoid dealing with this
arbitrary offset, Common Graphics sets the margins of a printer stream
to the distance from the physical offset to the margins selected by
the user in the print job dialog or page setup dialog. This allows
the application to maintain the requested paper margins by simply
drawing everything within the four margins that were set up
automatically. See *default-printer-left-margin*
for
more information.
Copyright (c) 1998-2016, Franz Inc. Oakland, CA., USA. All rights reserved.
This page was not revised from the 8.1 page.
Created 2010.1.21.
| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |