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DTL OTMaster


DTL OTMaster 6

Examine and Fix OpenType Fonts. For Mac and Windows.

The technical OpenType editor

An affordable font utility that allows users to visually edit the contents of tables in TrueType and OpenType fonts. DTL OTMaster is here! It's a major advance in font proofing and table-editing for Mac and Windows.

DTL OTMaster (OTM) is a highly sophisticated application for reviewing, editing and altering tables and contours of OpenType fonts (.otf and .ttf), TrueType fonts (.ttf) and TrueType Collection (.ttc) fonts, including CID-keyed OpenType fonts, CJK (Chinese, Korean, Japanese) and complex-script (Indic, Arabic etc.) fonts, and all the competing color OpenType font extensions: Microsoft “COLR”/“CPAL”, Adobe “SVG ”, Apple “sbix”, and Google “CBDT”/“CBLC”.

OTMaster 6 adds:

  • Support for Retina displays
  • Opens TTC made by AFDKO
  • Open & export WOFF and WOFF2 font formats
  • Glyph editor has more tools
  • OTM Text Viewer supports metrics editing
  • Tool icon size can be changed (in preferences)

The Glyph Editor is a compact version of DTL FontMaster: it is a fully-featured outline editor, allowing you to edit a glyph outline, import a glyph from and export it to EPS or SVG (so you can modify it another app and bring it back). You can change the glyph’s metrics, apply various transformations, automatic outline improvement operations, and autohinting. (New: in OTMaster 6: more glyph editing tools).

OTMaster 6 also provides a flurry of more specialized tools:

  • The Font Viewer allows you to preview all glyphs in a font, from all outline points to the rendered bitmaps at various sizes.
  • The Side by Side Viewer allows you to compare glyphs across a number of opened fonts, while the Color Viewer, the Embedded Bitmap Viewer and the Glyph Viewer allow you to examine specific aspects of each glyph.
  • The Table Comparator and the Consistency Checker help you achieve consistent behavior of all fonts in a family or one font across different operating systems.
  • With the GSUB/GPOS Table Viewer and the kern Table Viewer, you can perform detailed examination and do small modifications of the font’s layout behavior: kerning, mark positioning, contextual, ligature and other substitutions etc.
  • The Text Viewer is a comprehensive test environment for OpenType Layout features. You can preview customized strings, enable features selectively, choose the text script and direction, and export the renderings to PDF. OTMaster 5 integrates the cutting-edge HarfBuzz OpenType Layout engine, allowing you to accurately test the shaping and rendering of complex scripts such as Arabic or Devanagari.

DTL OTMaster is a technical OpenType font editor developerd by Dutch Type Library and URW++. This cross-platform tool allows detailed examination and modification of any OpenType font (.otf, .ttf or .ttc). OTMaster is typically used either at the last stage of font development, to perform final low-level changes, or to troubleshoot existing fonts by providing in-depth analysis and testing.

“OTMaster works with surgical precision: it will only modify the portions of the font that the developer wishes, leaving all other structures unchanged. This makes OTMaster a great companion to any font editor, and an indispensable element in even the most complex OpenType font production workflow.

OpenType (and TrueType) fonts consist of binary SFNT format tables, each performing a specialized task. For example, the “cmap” table maps glyphs to Unicode codepoints, the “name” table holds all internal font names and text, such as the family name, style name, copyright record, and license text. The “hhea” and “OS/2” tables provide information to the operating system about the font’s linespacing, character set, font weight and width, intended scaling and sizing of automatic superscript and subscript characters, and many other details. The “GSUB”, “GPOS” and “GDEF” tables hold all of the font’s advanced typographic OpenType layout features.

OTMaster provides precise editing access to all the font’s SFNT OpenType tables. You can view and modify almost every field in each table.

Examine, report, print

Learn how the OpenType font format works by viewing the inner structure of any OpenType font; export the contents of each font table as a plain-text or XML file; or print detailed glyph drawings or character maps. Each OpenType font file consists of a collection of "tables" &emdash; binary chunks of data identified by four-character names such as head, gasp, name, kern, GSUB, GPOS, glyf or CFF .

DTL OTMaster reveals the contents of any OpenType font table in a friendly "nested tree" view or in a comprehensive "text dump" mode.

OTM comes bundled with the OpenType font format specification (in the Documentation/OTM Manual resources folder inside the application's folder), so you can open a web browser side-by-side with OTM, and read the explanations for each table and all of its fields. It's an excellent way to learn the structure of the OpenType fonts and become familiar with how the fonts work.

In the nested tree mode, you can easily edit most of the font table's fields. You cand also view and export the contents of each font table as a plain-text or XML file, or print detailed glyph showings or character maps.

DTL OTMaster: 'glyf' table, Nested Tables view DTL OTMaster: 'name' table, Nested Tables view DTL OTMaster: 'OS/2' table, Nested Tables view DTL OTMaster: 'cmap' table, Nested Tables view DTL OTMaster: 'head' table, Text Dump view DTL OTMaster: 'gasp' table, Nested Tables view DTL OTMaster: 'gasp' table, Text Dump view DTL OTMaster: 'gasp' table, XML view

Add, copy or edit a glyph

OTM is a perfect tool in situations when the font you’re using is missing a glyph or an existing glyph has an inappropriate shape. You could accomplish this in any font editor, but OTM will perform the changes in an “non-invasive” manner: all of the font’s naming, hinting, kerning and OpenType Layout features will be intact — just as if you were using a high-precision surgical laser knife. This works even for CJK fonts and complex-script fonts such as Arabic or Indic!

With OTM’s Glyph Editor, you can add new glyphs to your font (Edit / New) or change existing glyphs using the built-in editing tools. You can even export the glyph into EPS or SVG, edit it in your favorite outline editing application (such as Adobe Illustrator), and import it back into the font (File / Import and File / Export). This allows you to add any symbols you want — not just letters, but also dingbats, personal signatures or company logos!

After you’ve modified the glyph shape or have created a new glyph, adjust its advance width to match your preferred spacing. Also, remember to turn on Hints, choose Transformation / Character Hinting and enable Autohinting. This will ensure that your modified glyph will look good on screen. Once you finished editing the glyph, close the Glyph Editor and click on the Discard Undo Information button.

If you've added a new glyph to the font, you may need to adjust its name and Unicode codepoint (so the glyph becomes accessible in applications that use the font). Open the Font Viewer, find the new glyph and double-click on it. This will open the Glyph Viewer, in which you can change the name and assign the Unicode codepoint. Remember to enter the same Unicode codepoint (e.g. 0x20ac if you added a € sign) in both Unicode and Microsoft; Unicode BMP only fields.

With the Glyph Copy Tool, you can copy a glyph (for example a special symbol or ornament) from one font to another. This will copy not only the glyph’s outline, but also its metrics, hints, and Unicode information.

DTL OTMaster: glyph viewer DTL OTMaster: glyph viewer DTL OTMaster: glyph editor DTL OTMaster: copy glyphs

Test and edit OpenType Layout features

One area where DTL OTMaster really shines is the ability to test and edit OpenType Layout features. The GSUB/GPOS Viewer tool allows you to visually check the GSUB replacements, and to test and edit kerning and GPOS positioning. You can also export feature definitions in AFDKO 2.5 format for later re-use.

One of the exciting aspects of OpenType is the powerful OpenType Layout mechanism. Rather than having a 1:1 relationship of glyphs and characters, and a plain kerning table, OpenType fonts allow for glyphs to be substituted, as well as precisely positioned (both horizontally and vertically). This can even be done contextually, i.e. only when a glyph is surrounded by specific other glyphs. Thanks to this, OpenType fonts can be “smart,” and include automatically inserted small caps, swashes, ligatures, stacking diacritical marks, or cursive attachment.

DTL OTMaster includes the GSUB/GPOS Viewer, a specialized module that allows you to visually check all of the font’s GSUB replacement commands and GPOS positioning rules. Some of the GPOS features such as kern or mark can be edited visually (along with the old-style TrueType kern table, in the kern Table Viewer).

All of the font's features can also be exported into .fea feature definition files that use the state-of-the-art Adobe FDK for OpenType (AFDKO) syntax, version 2.5. You can edit those files in a plain-text editor, and import them back into the original font — or into a different font, even if the font has a different character set. You can also use the feature definition files with FontLab Fontographer 5, which may save you a lot of time-consuming hand-coding.

DTL OTMaster: GSUB/GPOS viewer, GSUB table, Data view DTL OTMaster: GSUB/GPOS viewer, GSUB table, Report view DTL OTMaster: 'kern' table viewer DTL OTMaster: GSUB/GPOS viewer, GPOS table, 'kern' feature DTL OTMaster: GSUB/GPOS viewer, GPOS table, 'mark' feature DTL OTMaster: GSUB/GPOS viewer, GPOS table, 'mark' feature DTL OTMaster: GSUB/GPOS viewer, GPOS table, 'curs' feature

Fix families, linespacing, encoding

OTM’s Consistency Checker can automatically detect and correct family-linking, linespacing (vertical metrics) or encoding (Unicode range and codepage coverage) problems.

DTL OTMaster: Consistency checker DTL OTMaster: Consistency checker DTL OTMaster: Consistency checker DTL OTMaster: Consistency checker

Last-minute adjustments

The font looks too thin on the screen because of antialiasing, and you’d like to turn it off (in the gasp table)? Your favorite glyph is not accessible in your favorite application, so you need to add a PUA Unicode codepoint (in the cmap table or the glyph viewer)? The automatic underlining is too thin (the yStrikeout fields in the OS/2 table)? The sanserif font is a bit “too large on the body” compared to companion serif typeface (the unitsPerEm field in the head table)? OTMaster’s table-editing interface can help you fix all these problems without having to rebuild the font from sources — which might be a problem, especially for Chinese, Japanese, Korean, Hebrew, Arabic or Indic fonts.