Videonics PowerScript PS4000S, Инструкция по эксплуатации

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Chapter 7 Advanced PowerScript Functions
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Using Text in EPS Graphics
To use a vector-based EPS graphic containing text, the font files used to create the text
must be available to PowerScript on an inserted PC Card or as a ROM-resident font.
PowerScript comes with 35 different PostScript fonts. You can add other PostScript fonts
to PowerScript. (See Appendix A,
PowerScript Fonts , for a list of the PowerScript PostScript
fonts and instruction for importing font files.) Some of the PowerScript fonts also have
aliases that automatically substitute a specific font for one that might not be available.
For example, if an EPS file uses the Helvetica font, PowerScript automatically substitutes
its own Heavenetica font.
If an EPS graphic contains PostScript fonts that are not available to PowerScript, you can:
• Load the font into PowerScript (see “Importing Fonts” on page 196); or
• Convert the text-elements in the file to paths. Many illustration programs provide
this function as a built-in feature by converting each letter to a complex shape.
When you use this method, you do not have to load the PostScript font into Power-
Script and no substitution takes place. However, you can no longer easily edit the
text, and the complex shapes might take longer to process and display than the
text objects.
Tip
If an EPS file contains only a few text objects, converting them to outlines might be the best
solution. However, if the file contains a high volume of text (such as rolling production credits),
the best solution might be to import the PostScript fonts to PowerScript.
None of the preceding situations apply to bit-mapped images containing text because the
text is no longer in the form of characters. Within the bit-mapped image, the text charac-
ters no longer exist, so the font information is not needed.
The Square Pixel Factor
Most computer applications work with square pixels . Therefore, a rectangle that is 10 pix-
els high by 10 pixels wide looks like a perfect square. Digital video, however, uses non-
square pixels—so the 10x10 square is slightly taller than it is wide. The following table
shows the relative resolutions for NTSC and PAL systems.
PowerScript takes this distortion into account when it processes an image. For NTSC sys-
tems, PowerScript applies a 10% horizontal stretch to EPS graphics. Therefore, when cre-
ating EPS images simply create them as you normally would and PowerScript
automatically makes the necessary adjustments.
Table 11: Square Pixel Factors for NTSC and PAL Systems
NTSC
Non-square video screen pixels 720 x 485
Square pixels 640 x 480
PAL
Non-square video screen pixels 720 x 576
Square pixels 768 x 576