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Computing Oblique Rasters for Visual Representations

IP.com Disclosure Number: IPCOM000046846D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07

Publishing Venue

IBM

Related People

Authors:
Hehl, H [+details]

Abstract

Orthogonally oriented bit rasters with raster fields 1 and marked bits 2, as shown, for example, in Fig. 1, look like orthogonally oriented coarse rasters with the raster fields 3 (Fig. 2). To move such a coarse raster to an arbitrary angular position (Fig. 3), the bit pattern (Fig. 1) in the storage of a computer is converted, taking into account the desired angular position. For particular rotational angles a, this conversion can be easily made in a very short time, if the following condition is met (Fig. 4). n (a2 + b2) = p (a + b) $ a with tan a = a b where a, b, n, p are integers or multiples thereof. In accordance with this, a list (Fig. 5) of permissible angles is prepared. The asterisk in this list denotes that S', n, p are integers or multiples thereof.