@PARAFILTR ON = @BANNER = Ventura Publisher<190> @APP NOTE = Application Note #8 @NAME = Subjects: Screen font problems Bad WYSIWYG Display spacing problems The goal that all professional publishing software tries to achieve is to show an exact representation on the screen of what eventually gets printed. However, despite all the features built into Ventura Publisher, some of you have reported discrepancies between your computer screen and what gets printed. This lack of WYSIWYG (What You See Is What You Get) can usually be attributed to one or more of the following causes: @BULLET 1 = Screen aspect ratio doesn't match printer @BULLET 1 = Screen fonts don't match printer fonts. @BULLET 1 = Small number of pixels per character at small point sizes. @BULLET 1 = Width table altered. @BULLET 1 = New screen fonts have different resolution from existing screen fonts. @BULLET 1 = Helvetica or Times Roman fonts are missing. @BULLET 1 = Multiple spaces @BULLET 1 = Font changes within a line @BULLET 1 = Tabs & returns shown @BULLET 1 = Size not available The purpose of this application note is to describe these causes in more detail and to provide recommendations on how to minimize or eliminate the problems associated with each of these causes. By following these recommendations, you can be assured of an excellent display which very closely matches the printed output. @HEAD 1 = Aspect ratio Any computer display provides a different aspect ratio (i.e., ratio of height to width) than the final printed output. This difference can cause imperfections in how the character is placed on the screen. Some displays provide better aspect ratio than others. EGA and Hercules displays do not provide 1:1 aspect ratios and therefore are inferior to VGA displays which do. The only solution to this problem is to purchase a better display. @HEAD 1 = Screen fonts don't match printer Ventura Publisher is furnished with Times Roman and Helvetica screen fonts. However, to provide simple access to all the fonts which are embedded in many PostScript printers, Ventura Publisher includes a width table which contains the character information for all of these additional fonts. To provide an approximation of what the page will look like when these other fonts are chosen, Ventura Publisher automatically chooses Helvetica or Times Roman font for the screen display and then adjusts the position of the characters on the screen to compensate for the differences between the actual font and the Helvetica or Times Roman which is being used as a proxy. This results in characters with too much or too little spacing between them (see Figure 2). To solve this problem, you should purchase (or generate with Fontware) screen fonts which match the fonts with which you plan to print. PostScript screen fonts can be obtained from the Ventura Publisher User Group. Close approximations to PostScript fonts can be obtained using the fonts available from Bitstream for Fontware. @HEAD 1 = Insufficient number of pixels Most computer displays (e.g., a VGA display) are capable of producing a resolution which is equivalent to about 72 dots per inch. At this resolution, small characters (i.e., 12 points or less) are only 5 or 6 dots wide. Therefore, if a small character must be placed on the screen at a position equal to 5<$E1/2> dots from the last character, the screen only allows this character to be placed 5 dots or 6 dots from the last character. This half pixel error represents an error of more than 10% of the character's width. Because of how Ventura Publisher rounds numbers, the error can actually approach 20%, and with exceptionally small characters (such as 6 or 8 point), the percentage error can be even greater. This effect usually only becomes a problem when body text (or other small point size text) is kerned, because in this case Ventura Publisher tries to move adjacent characters by a small amount, but the lack of placement precision just described results in the character being moved way too far (see Figure 3). In many cases, the visual result on the screen for small type sizes is very distracting. The solution is to set the On-Screen Kerning feature in the Set Preferences option (Options menu) to 18 or greater. This will stop Ventura Publisher from trying to adjust small type sizes on the screen (the printed copy is not affected). As a side benefit, if you have automatic kerning turned on for Body Text, changing the on-screen kerning value dramatically improves screen drawing speed. (Automatic Pair Kerning is set in the Paragraph menu's Paragraph Typography option.) @HEAD 1 = Width table altered When you create a new width table, it is possible to create incorrect widths. For instance, if you try to merge widths for LaserJet fonts with a PostScript width table, Ventura Publisher will alert you to the pending problem, but will allow you to proceed if you choose. The resulting width table will almost certainly contain width information which doesn't match the printer in use. This in turn may result in an incorrect display and, unlike the other problems listed in this application note, will also result in a printed page which looks bad. The solution to this problem is to use a width table that has not yet been merged with another width table. By the way, Ventura Publisher lets you merge width tables for different printers because often different font vendors place a slightly different printer name in the printer width table (such as HP LaserJet instead of HP LJ+) even though the fonts are designed for the same printer. By letting you proceed with the merge, Ventura Publisher lets you merge the font information even though the identifying names do not precisely match. @HEAD 1 = Wrong screen fonts The fonts included with Ventura Publisher are CGA (640 x 200), EGA (640 x 350), or VGA (640 x 480) resolution. The VPPREP installation program automatically installs the correct screen fonts for the display driver you choose. If you later create more screen fonts using Fontware or add screen fonts provided by any one of many font vendors, if the resolution of these screen fonts is different from those already installed, you may find that the fonts appear to large or too small (see Figure 4). Ventura Publisher does allow you to mix fonts of different resolutions, but to avoid these kinds of problems, only use those which have the same resolution of those already in use. @HEAD 1 = Helvetica or Times screen fonts replaced. Ventura Publisher is hard-wired to expect both Helvetica and Times Roman fonts. If you create a width table which contains neither of these fonts, the results can be quite unpredictable. Usually the screen magnification changes dramatically. Instead of seeing <$E1/3> of the screen in normal view, you will suddenly see only <$E1/6> or less. The solution is to merge the faulty width table with one which contains either Helvetica or Times Roman, preferably both. @HEAD 1 = Size not available Ventura Publisher provides screen fonts in various discrete sizes (6, 8, 9, 10, 11, 12, 14, 18, 24) and in normal weight. When you request a size (e.g., 13 point) or weight (e.g, italic) for which no screen font is available, Ventura Publisher creates one in real time by adding or deleting pixels from the nearest available size (see Figure 5). The algorithm used was optimized for speed, but the results are notably poorer than what you obtain when displaying a font size for which a screen font is available. The screen also draws more slowly. The solution is to create a screen font for each size and weight using Fontware, or else purchase these screen fonts from your favorite font vendor. Note that each screen font is stored in a separate file, so even if you have the money to buy or (with Fontware) the time to generate lots of screen fonts, you should do so judiciously or you will find your hard disk suddenly has been eaten up by huge numbers of screen font files. Ventura Publisher can handle a maximum of about 700 screen font files at once. @HEAD 1 = Tabs & returns shown One of the most common problems with the screen display not matching the printed output is caused by using the Show Tabs & Returns option. This option is available in the Options menu and represents all hidden features (e.g., index points, references) and characters (e.g., tabs, line breaks, returns) by some appropriate marker character. Because these characters don't appear on the printed page, and because each line of text still ends at the same position on the page, the characters on the line must be crowded together to make room for all the markers. The obvious solution to this problem is to temporarily Hide Tabs & Returns (Options menu). @HEAD 1 = Font changes within a line While in the Text mode, you can select a range of text and then change its font using the Set Font feature (available in the Assignment List while in Text mode). In most situations, the resulting text looks just fine on the screen. However, when some of the other problems described in this application note are present, selecting a different font can magnify the problem, especially if the new font is larger. The solution to this problem varies, but usually involves solving one of the other problems mentioned in this note. @HEAD 1 = Multiple spaces Ventura Publisher does not <169>like<170> more than one space between words. This is due to the fact that extra spaces can cause major problems when they get placed at the end of a line. For example, suppose a line of text contains three spaces between a pair of words. Suppose further that while formatting this line, the first of the two words happens to fall at the end of a line. If Ventura Publisher didn't do something clever, that line would appear to be justified incorrectly. The solution to this problem is that when loading a text file, Ventura Publisher converts multiple spaces to one space plus multiple non-breaking spaces. A non-breaking space is treated the same as a normal space (i.e., it can be compressed or expanded during justification), but it always forces the adjacent characters or words to be pulled to the next line. When the adjoining character is a space, the effect is to pull the space to the next line. Since Ventura Publisher suppresses all spaces at the beginning of a line (both regular as well as non-breaking), the effect is to remove all excess spaces when they fall at the end of the line. It is a good solution to a very real problem. However, this whole process can cause Ventura Publisher to move letters slightly to the left or right of their correct position within the words adjacent to these extra spaces when those spaces do not fall at the end of a line. The solution is to: @BULLET 1 = Select the Text mode. @BULLET 1 = Move the text cursor through the text in the area where you observe the problem. Keep your eye on the Current Selection Box in the lower left corner of the screen. @BULLET 1 = When you see the words NoBreak Space, press the Del key to delete the extra space. This problem is most often noticed by PostScript users because the screen fonts used in Ventura Publisher were derived from Bitstream outline. These outlines do not match the set widths of Adobe's (i.e., PostScript's) typefaces. To solve the problem, puchase the matching screen fonts from Adobe Systems. You should note that, like the other problems mentioned in this note, this one only affects the screen display. Therefore, you may choose to ignore it since the printed page will look OK. @HEAD 1 = Summary The differences between a computer display and a piece of paper make it impossible to achieve perfect WYSIWYG. However, you can achieve excellent results for even the most critical applications if you do the following: @BULLET 1 = Set On-Screen Kerning (Set Preferences option in the Options menu) to 18. Unless you own a very high resolution display, you should never display kerning on the screen for sizes under 18 points. As a side benefit, you will notice a marked improvement in screen drawing performance if you have kerning turned on for the majority of text on a page. @BULLET 1 = For every typeface, generate or purchase screen fonts which match each size and weight you plan to use. @BULLET 1 = Make sure the width table you use has not been merged with a width table for another printer, and make sure Helvetica and Times Roman (or Swiss and Dutch) are still contained in the Font list in the Paragraph menu's Font option. @BULLET 1 = Hide tabs & returns. @BULLET 1 = Eliminate multiple spaces (created by pressing the space bar) between words.