DLI Implementation and Reference Guide - Datalogics

10.16. DLI Implementation and Reference Guide
Matrix Translations
The unity matrix ([1, 0, 0, 1, 0, 0]) causes a 1 unit movement in X to be a 1
Concepts and Facilities: Guide to the DL Pager Composition System
unit movement in X and a zero unit movement in Y; a 1 unit movement in Y becomes
a 0 unit movement in X and a 1 unit movement in Y.
More precisely:
RealX = X * a + Y * c + h
RealY = X * b + Y * d + v
Hence:
• the matrix [1 0 0 -1 0 0] will invert the figure drawn
• the matrix [-1 0 0 1 0 0] will mirror-image the figure
• the matrix [.707 .707 -.707 .707 0 0] will rotate it 45 degrees
Image Translation
Translation is the simple movement of the image, and is accomplished by modifying h
and/or v. These values are interpreted in the un-transformed space. For more details,
please see section 4.2.2, "Common Transformations," in the Portable Document
Format Reference Manual.
Image Rotation
A matrix may be rotated by using the method dlpdfmatrixrotate. This method
accepts a pointer to a matrix, and transforms it to accomplish a rotation of the
specified angle (in degrees, as an ASFixed value, counter-clockwise).
Image Shearing and Scaling
Shearing of an image may be accomplished by modifying b or c only. Scaling may be
accomplished by modifying a and/or d only.
CAUTION: Be sure to scale before rotating, if you are doing both.