Glyph objects represent a glyph in the font. They have various properties for accessing metrics and the actual vector path the glyph represents, and methods for rendering the glyph to a graphics context. You do not create glyph objects directly. They are created by various methods on the font object, described above. There are several subclasses of the base Glyph class internally that may be returned depending on the font format, but they all include the following API.
Fontkit has support for several different color emoji font formats. Here is an overview of the various color font formats out there. For SBIX glyphs, which are bitmap based, this returns an object containing some properties about the image, along with the image data itself usually PNG. For COLR glyphs, which are vector based, this returns an array of objects representing the glyphs and colors for each layer in render order.
Path objects are returned by glyphs and represent the actual vector outlines for each glyph in the font. Paths can be converted to SVG path data strings, or to functions that can be applied to render the path to a graphics context. Adds a quadratic curve to the path from the current point to the given x, y coordinates using cpx, cpy as a control point.
Adds a bezier curve to the path from the current point to the given x, y coordinates using cp1x, cp1y and cp2x, cp2y as control points.
Compiles the path to a JavaScript function that can be applied with a graphics context in order to render the path. This is the exact bounding box, taking into account control points that may be outside the visible shape. It is like the bounding box, but it includes all points of the path, including control points of bezier segments. It is much faster to compute than the real bounding box, but less accurate if there are control points outside of the visible shape.
Fontkit can perform font subsetting, i. This is useful to reduce the size of large fonts, such as in PDF generation or for web use. Currently, subsets produce minimal fonts designed for PDF embedding that may not work as standalone files. They have no cmap tables and other essential tables for standalone use. This limitation will be removed in the future. You create a Subset object by calling font. The API on Subset objects is as follows.
Returns a stream containing the encoded font file that can be piped to a destination, such as a file. Listed below are changes that have been made in this fork: Store binary data as compressed base64 JSON so the fs module isn't needed to read it back: e35c 99a35c7 2fd fbf2-R24 , fbf2-R13 Rewrote Makefile to Makefile.
Features Suports TrueType. IXDocReport; import fr. XDocReportRegistry; import fr. IContext; import fr. TemplateEngineKind; import fr. The rendered text in PDF should have a tab character in it. The text was updated successfully, but these errors were encountered:. Lines to in bff Lines 42 to 45 in bff Sorry, something went wrong. Skip to content. Star 2. New issue.
Jump to bottom. Labels bug help wanted. A Ligature Substitution LigatureSubst subtable identifies ligature substitutions where a single glyph replaces multiple glyphs.
One LigatureSubst subtable can specify any number of ligature substitutions. The subtable has one format: LigatureSubstFormat1. It contains a format identifier substFormat , a Coverage table offset coverageOffset , a count of the ligature sets defined in this table ligatureSetCount , and an array of offsets to LigatureSet tables ligatureSetOffsets. The Coverage table specifies only the index of the first glyph component of each ligature set.
Example 6 at the end of this chapter shows how to replace a string of glyphs with a single ligature. A LigatureSet table, one for each covered glyph, specifies all the ligature strings that begin with the covered glyph. A LigatureSet table consists of a count of the ligatures that begin with the covered glyph ligatureCount and an array of offsets ligatureSetOffsets to Ligature tables, which define the glyphs in each ligature.
The order in the Ligature offset array defines the preference for using the ligatures. For each ligature in the set, a Ligature table specifies the glyph ID of the output ligature glyph ligatureGlyph ; a count of the total number of component glyphs in the ligature, including the first component componentCount ; and an array of glyph IDs for the components componentGlyphIDs. Note: The componentGlyphIDs array lists glyph IDs according to the writing direction — that is, the logical order — of the text.
For text written right to left, the right-most glyph will be first. Conversely, for text written left to right, the left-most glyph will be first. A Contextual Substitution subtable describes glyph substitutions in context that replace one or more glyphs within a certain pattern of glyphs.
These define input sequence patterns to be matched against the text glyph sequence, and then actions to be applied to glyphs within the input sequence. Examples 7 , 8 , and 9 at the end of this chapter illustrate use of sequence lookup records within the GSUB table. In this way, actions specified by a GSUB contextual lookup can only be substitutions. An input sequence pattern is matched against the current glyph sequence before any substitution actions are performed.
The substitutions may change the current glyph sequence, but that has no affect on the initial matching operation. For a given lookup subtable, there may be multiple sequence lookup records, and these are processed in a specified order. Each substitution action on the glyph sequence applies to the results from the preceding sequence lookup records.
Note in particular that the sequence position index in each sequence lookup record is relative to the glyph sequence as modified by the preceding actions. For example, consider a contextual lookup specifying an input glyph sequence of four glyphs. Suppose that no substitution is performed on the first glyph, but that the middle two glyphs will be replaced with a ligature, and a single glyph will replace the fourth glyph. Suppose also that the actions are listed in that order.
Format 1 defines the context for a glyph substitution as a particular sequence of glyphs. Format 1 contextual substitutions are implemented using a SequenceContextFormat1 table. Example 7 at the end of the chapter uses a SequenceContextFormat1 table to replace a sequence of three glyphs with a sequence preferred for the French language system.
Format 2 defines contexts for glyph substitutions as input sequence patterns, with patterns expressed in terms of glyph classes. The glyph classes are defined using a Class Definition table.
Several sequence patterns may be specified, with each pattern specifying a class of glyphs for each input sequence position. For example, suppose that a swash capital glyph should replace each uppercase letter glyph that is preceded by a space glyph and followed by a lowercase letter glyph a glyph sequence of space - uppercase - lowercase. The set of uppercase glyphs would constitute one glyph class Class 1 , the set of lowercase glyphs would constitute a second class Class 2 , and the space glyph would constitute a third class Class 3.
The input context might be specified as a pattern of one glyph from Class 3, followed by one glyph from Class 1, followed by one glyph from Class 2. Format 2 contextual substitutions are implemented using a SequenceContextFormat2 table. Example 8 at the end of this chapter uses a SequenceContextFormat2 table to substitute Arabic mark glyphs for base glyphs of different heights.
Format 3 defines a context for glyph substitutions as an input sequence pattern, with the pattern expressed in terms of Coverage tables. A different Coverage table is defined for each sequence position. Format 3 is like format 2 in that patterns are defined using sets of glyphs.
However, with the glyph classes used in format 2, each glyph is in exactly one class. With format 3, any glyph can occur in multiple Coverage tables. For example, consider an input context that contains a lowercase glyph position 0 , followed by an uppercase glyph position 1 , either a lowercase or numeral glyph position 2 , and then either a lowercase or uppercase vowel position 3.
This context requires four Coverage tables, one for each position:. Format 3 contextual substitutions are implemented using a SequenceContextFormat3 table. Example 9 at the end of this chapter uses SequenceContextFormat3 to substitute swash glyphs for two out of three glyphs in a sequence.
The design of the Chained Contexts Substitution subtable is parallel to that of the Contextual Substitution subtable, including the availability of three formats. Each format can describe one or more chained backtrack, input, and lookahead sequence combinations, and one or more substitutions for glyphs in each input sequence. Note: Substitutions can be specified only for the input sequence context, not for backtrack and lookahead sequences.
See the introduction to the Contextual Substitution Subtable section for general remarks regarding contextual substitutions, which also apply to Chained Contexts Substitutions.
Note that backtrack sequences are specified in reverse logical order. Specific glyph sequences are used for input, backtrack or lookahead contexts. Format 1 chained context substitutions are implemented using a ChainedSequenceContextFormat1 table. Format 2 defines contexts for glyph substitutions as patterns expressed in terms of glyph classes. Several sequence patterns may be specified, with each pattern specifying a class of glyphs for each sequence position.
To chain contexts, three separate Class Definition tables are used for the backtrack sequence, input sequence, and lookahead sequence. Format 2 contextual substitutions are implemented using a ChainedSequenceContextFormat2 table. Format 3 defines contexts for glyph substitutions as patterns expressed in terms of Coverage tables. A different Coverage table is defined for each position in a sequence.
To chain contexts, three separate sets of Coverage tables are used for the backtrack sequence, input sequence, and lookahead sequence. Format 3 contextual substitutions are implemented using a ChainedSequenceContextFormat3 table. This lookup type provides a way to access lookup subtables within the GSUB table using bit offsets.
This is needed if the total size of the subtables exceeds the bit limits of the various other offsets in the GSUB table. The extensionLookupType field must be set to any lookup type other than 7. If a lookup table uses extension subtables, then all of the extension subtables must have the same extensionLookupType. All offsets to extension subtables are set in the usual way—that is, relative to start of the ExtensionSubstFormat1 subtable. The major difference between this and other lookup types is that processing of input glyph sequence goes from end to start.
Compared to the Chaining Contextual Sustitution lookup subtable type 6 , this format is restricted to only a coverage-based subtable format, input sequences can contain only a single glyph, and only single substitutions are allowed on this glyph. This constraint is integrated into the subtable format. Format 1 defines a chaining context rule as a sequence of Coverage tables.
Each position in the sequence may define a different Coverage table for the set of glyphs that matches the context pattern. With Format 1, the glyph sets defined in the different Coverage tables may intersect.
Note: Despite reverse order processing, the order of the Coverage tables listed in the Coverage array must be in logical order follow the writing direction. The input sequence is one glyph located at i in the logical string. The backtrack begins at i - 1 and increases in offset value as one moves toward the logical beginning of the string.
In processing a reverse chaining substitution, i begins at the logical end of the string and moves to the beginning. The subtable contains a Coverage table for the input glyph and Coverage table arrays for backtrack and lookahead sequences. It also contains an array of substitute glyph indices substituteGlyphIDs , which are substititions for glyphs in the Coverage table, and a count of glyphs in the substituteGlyphIDs array. Example 10 at the end of this chapter uses ReverseChainSingleSubstFormat1 to substitute Arabic glyphs with a correct stroke thickness on the left exit to match the stroke thickness on the right entry of the following glyph in logical order.
The rest of this chapter describes and illustrates examples of all the GSUB subtables, including each of the three formats available for contextual substitutions.
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