Browse Prior Art Database

Keystone Adjustment for Document Composition

IP.com Disclosure Number: IPCOM000112958D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Blalock, JL: AUTHOR [+2]

Abstract

Existing document composition programs, such as IBM's DCF Script, allow for creation of FOILS to be shown via overhead projectors. There is no provision for correction of the keystone effect which detracts from the presentation.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Keystone Adjustment for Document Composition

      Existing document composition programs, such as IBM's DCF
Script, allow for creation of FOILS to be shown via overhead
projectors.  There is no provision for correction of the keystone
effect which detracts from the presentation.

      This disclosure provides for specialized tags which specify the
degree of pre-distortion needed to enable correct projection.  The
adjustment can be for vertical, horizontal, or concurrent
corrections.

      Actual implementation could vary but one implementation could
look like this:  VDist=4,8 HDist=5,8;  would signal the end of
correction.

      This would over-ride the system defaults by specifying in feet
(alternate default measurement could be meters) that the Vertical
distance from projector is +4 feet high and 8 feet from table to
screen.  Similarly, horizontal offset 5 is feet off-center
(Left/Right), again 8 feet from projector table to the screen.

      The formatting program would then take the APA (All Point
Addressable) output which could be 600 DPI for AFP printers, and
mathematically distort the picture by removing pels.  This
pre-distortion would then be distorted INTO proper perspective using
standard overhead projectors.

Multiple levels of correction can be provided:

1.  Quick and easy (assume text mode) Use series of fonts that are
    defined with correct slant optimized for distortion angle.  The
    top of the foil would default to...