Depending on which OS you’re on and which application you’re in, a different set is used for rendering the font on the screen.To line up page numbers vertically at the right margin requires that the. STypo or OS/2) and win (or usWin) metrics. They’re known as hhea, typo (a.k.a. When you align objects relative to each other by their middles or centers, the objects are aligned along a horizontal or vertical line that represents the average of their original positions.For historical reasons, there are no less than three sets of values that deal with your vertical metrics. Align Middle aligns objects horizontally through the middles of the objects and Align Center aligns objects vertically through the centers of the objects.Custom parametersIn Excel 2013, you can also use slicers on formatted Excel tables. You may run into problems, however, if these values change between masters. Fortunately, Glyphs does its best to calculate them based on the vertical metrics you enter for each of your masters: ascender, cap height, x-height and descender. The vertical ruler is always available for page layout documents.Unfortunately, all of these values relate to each other in a pretty complicated way. For word-processing documents like a letter or report, you need to turn on the vertical ruler in Pages preferences. Pages provides horizontal and vertical rulers to help you lay out text and objects in your document.
HheaThe name hhea refers to the hhea OpenType table. Set the values in one master, then copy and paste the parameters into the Custom Parameters fields of all other masters.But what do these values mean? Let me give you a quick rundown. You will do this with custom parameters in File > Font Info > Masters (Cmd-I). Talk to text software for machheaDescender: the depth of the descenders in units (negative value) hheaAscender: the height of the ascenders in units For convenience, I will list them here with the custom parameter names that Glyphs uses: The hhea table knows three vertical metrics values. Apple devices such as Macs, iPhones, iPads, etc., use these values for rendering. ![]() Windows supposedly uses these values to find the ideal parameters for layout thus we have a certain degree of artistic freedom.’The big layout apps, XPress and InDesign, use the typoAscender and typoDescender values to determine the offset of the first baseline in a text box and the minimum size of a text box below which the display of type is suppressed. typoLineGap: the recommended whitespace between linesTo quote Yannis Haralambous (p.724), these values ‘are oddly similar to ascent, descent, and lineGap in the hhea table but that should not necessarily be so precise or so closely tied to the vagaries of the glyphs’ outlines. typoDescender: the depth of the descenders in units (negative value) These values should be set to provide default line spacing appropriate for the primary languages the font is designed to support.(Source: OS/2 sTypoAscender specification on Microsoft Typography)_Yet, the UPM dogma still plays a role in the (legacy) Adobe and Microsoft strategies discussed below. One of the proponents of letting go of the UPM dogma was Victor Gaultney from SIL, who wrote both Best Practice: Design Metrics and Best Practice: Line Metrics.In the meantime, the dogma was dropped altogether from the OpenType specification:It is not a general requirement that sTypoAscender - sTypoDescender be equal to unitsPerEm. This used to make things really complicated.A few years ago, the ‘UPM dogma’ has gotten under fire, because it simply did not work for scripts that require different metrics than Latin. In the dark past of electronic typesetting, the TrueType/OpenType specifications used to stipulate that the span from typoAscender to typoDescender should be as large as the font’s UPM (usually 1000 or 2048). The UPM dogmaThere is one thing you need to watch out for, though: the ‘UPM dogma’. In that case, typoLineGap will be respected as well. Hence, the easiest way, it seems, is to make sure everything in the font fits into the win span. winDescent: the bottom extremum of the font rendering box (positive value)Attention: whatever extends above or below these values, will likely be cut off when rendered by the Windows text engine. winAscent: the top extremum of the font rendering box According to the MakeOTF User Guide, this bit was introduced ‘so that reflow of documents will happen less often than if Microsoft just changed the behaviour for all fonts.’All modern fonts should have this parameter. If you can safely ignore older (i.e., pre-2006) MS Office versions, you should add a Use Typo Metrics parameter to File > Font Info > Font. If checked, applications that respect this setting (in particular, versions of Microsoft Office since 2006) will prefer typoAscender, typoDescender, and typoLineGap over winAscent and winDescent for determining the vertical positioning.Technically, what it does is set bit 7 (‘don’t use Win line metrics’) of the fsSelection field in the OS/2 table. Use Typo MetricsThere is one more thing. For every master, highest and deepest points in all glyphs will be listed. ![]() Most likely the Microsoft Strategy (see below) will be a good idea then. If you find the correct display of underlines in Microsoft Word more important than proper linespacing, disable Use Typo Metrics, and follow one of the legacy strategies. If Use Typo Metrics is on, default underline values will be used instead. Therefore, if you need a good overall compromise for DTP, Office and web use, I recommend to employ the Webfont strategy described below. But keep in mind that both of these strategies are outdated because they both adhere to the UPM dogma. They are handy to know because you may have to make your font compatible with legacy software. First, two historical methods, the Adobe and Microsoft strategies. Let me show you the most popular strategies for manually setting your vertical metrics. Advantage: better synchronization of font display between Mac apps and layout apps (XPress, InDesign), and usually tight default leading. So it may be a good idea to use this method if your font has a low x-height (below half UPM). Font Info > Font > Custom Parameters: Use Typo Metrics = yesWith this strategy, the linegap tends towards the small end of the spectrum. hheaLineGap = winAscent + winDescent – UPM Subtract your UPM value from that sum and put the result into typoLineGap.With this strategy, the linegap tends towards the large end of the spectrum. In this strategy, the sum of the hhea and win ascender and descender will most likely be much more than 1000, or whatever your UPM is. −200), you put the rest (800) into typoAscender. You could put the depth of the descender into typoDescender (e.g. typoLineGap = winAscent + winDescent – UPMFor the rest, as already mentioned above, the span from typoAscender to typoDescender must add up to your UPM value (usually 1000). hheaDescender = − winDescent (negative value) Vertical Alignment Table Word 2011 Plus Half OfWhen text is placed inside an HTML element such as or , these browsers will add hheaAscender plus half of hheaLineGap, and use this to calculate the position of the first baseline in respect to the top edge of the HTML element. In our opinion, it is the most compatible compromise for vertical metrics.On the Mac, the Safari and Chrome browsers use the hhea values for positioning text, regardless of the Use Typo Metrics setting. Disadvantage: differences between Mac apps and layout apps (XPress, InDesign), and default leading may appear to be too much.We support and recommend the webfont strategy. Advantages: better synchronization of font display between Win and Mac apps accents are not cut off in Mac apps because winAscent tends to be higher than typoAscender. ![]()
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