Python2/PyMuPDF: mupdf-source/thirdparty/harfbuzz/docs/usermanual-what-is-harfbuzz.xml annotate

annotate mupdf-source/thirdparty/harfbuzz/docs/usermanual-what-is-harfbuzz.xml @ 22:d77477b4e151

Let _int_rc() also handle (i.e. ignore) a local version suffix

author	Franz Glasner <fzglas.hg@dom66.de>
date	Fri, 19 Sep 2025 12:05:57 +0200
parents	b50eed0cc0ef
children

rev	line source
2 b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	1 <?xml version="1.0"?>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	3 "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	4 <!ENTITY % local.common.attrib "xmlns:xi CDATA #FIXED 'http://www.w3.org/2003/XInclude'">
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	5 <!ENTITY version SYSTEM "version.xml">
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	6 ]>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	7 <chapter id="what-is-harfbuzz">
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	8 <title>What is HarfBuzz?</title>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	9 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	10 HarfBuzz is a <emphasis>text-shaping engine</emphasis>. If you
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	11 give HarfBuzz a font and a string containing a sequence of Unicode
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	12 codepoints, HarfBuzz selects and positions the corresponding
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	13 glyphs from the font, applying all of the necessary layout rules
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	14 and font features. HarfBuzz then returns the string to you in the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	15 form that is correctly arranged for the language and writing
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	16 system.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	17 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	18 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	19 HarfBuzz can properly shape all of the world's major writing
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	20 systems. It runs on all major operating systems and software
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	21 platforms and it supports the major font formats in use
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	22 today.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	23 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	24 <section id="what-is-text-shaping">
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	25 <title>What is text shaping?</title>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	26 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	27 Text shaping is the process of translating a string of character
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	28 codes (such as Unicode codepoints) into a properly arranged
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	29 sequence of glyphs that can be rendered onto a screen or into
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	30 final output form for inclusion in a document.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	31 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	32 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	33 The shaping process is dependent on the input string, the active
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	34 font, the script (or writing system) that the string is in, and
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	35 the language that the string is in.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	36 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	37 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	38 Modern software systems generally only deal with strings in the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	39 Unicode encoding scheme (although legacy systems and documents may
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	40 involve other encodings).
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	41 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	42 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	43 There are several font formats that a program might
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	44 encounter, each of which has a set of standard text-shaping
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	45 rules.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	46 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	47 <para>The dominant format is <ulink
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	48 url="http://www.microsoft.com/typography/otspec/">OpenType</ulink>. The
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	49 OpenType specification defines a series of <ulink url="https://github.com/n8willis/opentype-shaping-documents">shaping models</ulink> for
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	50 various scripts from around the world. These shaping models depend on
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	51 the font incorporating certain features as
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	52 <emphasis>lookups</emphasis> in its <literal>GSUB</literal>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	53 and <literal>GPOS</literal> tables.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	54 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	55 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	56 Alternatively, OpenType fonts can include shaping features for
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	57 the <ulink url="https://graphite.sil.org/">Graphite</ulink> shaping model.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	58 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	59 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	60 TrueType fonts can also include OpenType shaping
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	61 features. Alternatively, TrueType fonts can also include <ulink url="https://developer.apple.com/fonts/TrueType-Reference-Manual/RM09/AppendixF.html">Apple
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	62 Advanced Typography</ulink> (AAT) tables to implement shaping
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	63 support. AAT fonts are generally only found on macOS and iOS systems.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	64 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	65 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	66 Text strings will usually be tagged with a script and language
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	67 tag that provide the context needed to perform text shaping
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	68 correctly. The necessary <ulink
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	69 url="https://docs.microsoft.com/en-us/typography/opentype/spec/scripttags">script</ulink>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	70 and <ulink
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	71 url="https://docs.microsoft.com/en-us/typography/opentype/spec/languagetags">language</ulink>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	72 tags are defined by OpenType.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	73 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	74 </section>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	75
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	76 <section id="why-do-i-need-a-shaping-engine">
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	77 <title>Why do I need a shaping engine?</title>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	78 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	79 Text shaping is an integral part of preparing text for
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	80 display. Before a Unicode sequence can be rendered, the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	81 codepoints in the sequence must be mapped to the corresponding
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	82 glyphs provided in the font, and those glyphs must be positioned
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	83 correctly relative to each other. For many of the scripts
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	84 supported in Unicode, these steps involve script-specific layout
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	85 rules, including complex joining, reordering, and positioning
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	86 behavior. Implementing these rules is the job of the shaping engine.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	87 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	88 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	89 Text shaping is a fairly low-level operation. HarfBuzz is
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	90 used directly by text-handling libraries like <ulink
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	91 url="https://www.pango.org/">Pango</ulink>, as well as by the layout
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	92 engines in Firefox, LibreOffice, and Chromium. Unless you are
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	93 <emphasis>writing</emphasis> one of these layout engines
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	94 yourself, you will probably not need to use HarfBuzz: normally,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	95 a layout engine, toolkit, or other library will turn text into
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	96 glyphs for you.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	97 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	98 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	99 However, if you <emphasis>are</emphasis> writing a layout engine
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	100 or graphics library yourself, then you will need to perform text
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	101 shaping, and this is where HarfBuzz can help you.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	102 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	103 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	104 Here are some specific scenarios where a text-shaping engine
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	105 like HarfBuzz helps you:
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	106 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	107 <itemizedlist>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	108 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	109 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	110 OpenType fonts contain a set of glyphs (that is, shapes
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	111 to represent the letters, numbers, punctuation marks, and
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	112 all other symbols), which are indexed by a <literal>glyph ID</literal>.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	113 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	114 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	115 A particular glyph ID within the font does not necessarily
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	116 correlate to a predictable Unicode codepoint. For instance,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	117 some fonts have the letter "a" as glyph ID 1, but
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	118 many others do not. In order to retrieve the right glyph
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	119 from the font to display "a", you need to consult
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	120 the table inside the font (the <literal>cmap</literal>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	121 table) that maps Unicode codepoints to glyph IDs. In other
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	122 words, <emphasis>text shaping turns codepoints into glyph
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	123 IDs</emphasis>.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	124 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	125 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	126 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	127 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	128 Many OpenType fonts contain ligatures: combinations of
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	129 characters that are rendered as a single unit. For instance,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	130 it is common for the "f, i" letter
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	131 sequence to appear in print as the single ligature glyph
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	132 "ﬁ".
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	133 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	134 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	135 Whether you should render an "f, i" sequence
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	136 as <literal>fi</literal> or as "ﬁ" does not
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	137 depend on the input text. Instead, it depends on the whether
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	138 or not the font includes an "ﬁ" glyph and on the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	139 level of ligature application you wish to perform. The font
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	140 and the amount of ligature application used are under your
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	141 control. In other words, <emphasis>text shaping involves
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	142 querying the font's ligature tables and determining what
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	143 substitutions should be made</emphasis>.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	144 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	145 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	146 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	147 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	148 While ligatures like "ﬁ" are optional typographic
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	149 refinements, some languages <emphasis>require</emphasis> certain
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	150 substitutions to be made in order to display text correctly.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	151 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	152 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	153 For example, in Tamil, when the letter "TTA" (ட)
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	154 letter is followed by the vowel sign "U" (ு), the pair
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	155 must be replaced by the single glyph "டு". The
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	156 sequence of Unicode characters "ட,ு" needs to be
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	157 substituted with a single "டு" glyph from the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	158 font.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	159 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	160 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	161 But "டு" does not have a Unicode codepoint. To
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	162 find this glyph, you need to consult the table inside
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	163 the font (the <literal>GSUB</literal> table) that contains
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	164 substitution information. In other words, <emphasis>text shaping
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	165 chooses the correct glyph for a sequence of characters
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	166 provided</emphasis>.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	167 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	168 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	169 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	170 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	171 Similarly, each Arabic character has four different variants
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	172 corresponding to the different positions it might appear in
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	173 within a sequence. Inside a font, there will be separate
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	174 glyphs for the initial, medial, final, and isolated forms of
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	175 each letter, each at a different glyph ID.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	176 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	177 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	178 Unicode only assigns one codepoint per character, so a
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	179 Unicode string will not tell you which glyph variant to use
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	180 for each character. To decide, you need to analyze the whole
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	181 string and determine the appropriate glyph for each character
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	182 based on its position. In other words, <emphasis>text
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	183 shaping chooses the correct form of the letter by its
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	184 position and returns the correct glyph from the font</emphasis>.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	185 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	186 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	187 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	188 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	189 Other languages involve marks and accents that need to be
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	190 rendered in specific positions relative a base character. For
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	191 instance, the Moldovan language includes the Cyrillic letter
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	192 "zhe" (ж) with a breve accent, like so: "ӂ".
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	193 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	194 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	195 Some fonts will provide this character as a single
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	196 zhe-with-breve glyph, but other fonts will not and, instead,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	197 will expect the rendering engine to form the character by
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	198 superimposing the separate "ж" and "˘"
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	199 glyphs.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	200 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	201 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	202 But exactly where you should draw the breve depends on the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	203 height and width of the preceding zhe glyph. To find the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	204 right position, you need to consult the table inside
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	205 the font (the <literal>GPOS</literal> table) that contains
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	206 positioning information.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	207 In other words, <emphasis>text shaping tells you whether you
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	208 have a precomposed glyph within your font or if you need to
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	209 compose a glyph yourself out of combining marks—and,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	210 if so, where to position those marks.</emphasis>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	211 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	212 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	213 </itemizedlist>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	214 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	215 If tasks like these are something that you need to do, then you
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	216 need a text shaping engine. You could use Uniscribe if you are
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	217 writing Windows software; you could use CoreText on macOS; or
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	218 you could use HarfBuzz.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	219 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	220 <note>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	221 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	222 In the rest of this manual, the text will assume that the reader
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	223 is that implementor of a text-layout engine.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	224 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	225 </note>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	226 </section>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	227
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	228
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	229 <section id="what-does-harfbuzz-do">
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	230 <title>What does HarfBuzz do?</title>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	231 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	232 HarfBuzz provides text shaping through a cross-platform
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	233 C API that accepts sequences of Unicode codepoints as input. Currently,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	234 the following OpenType shaping models are supported:
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	235 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	236 <itemizedlist>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	237 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	238 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	239 Indic (covering Devanagari, Bengali, Gujarati,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	240 Gurmukhi, Kannada, Malayalam, Oriya, Tamil, and Telugu)
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	241 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	242 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	243 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	244 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	245 Arabic (covering Arabic, N'Ko, Syriac, and Mongolian)
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	246 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	247 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	248 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	249 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	250 Thai and Lao
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	251 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	252 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	253 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	254 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	255 Khmer
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	256 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	257 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	258 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	259 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	260 Myanmar
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	261 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	262 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	263
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	264 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	265 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	266 Tibetan
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	267 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	268 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	269
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	270 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	271 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	272 Hangul
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	273 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	274 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	275
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	276 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	277 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	278 Hebrew
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	279 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	280 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	281 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	282 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	283 The Universal Shaping Engine or <emphasis>USE</emphasis>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	284 (covering complex scripts not covered by the above shaping
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	285 models)
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	286 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	287 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	288 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	289 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	290 A default shaping model for non-complex scripts
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	291 (covering Latin, Cyrillic, Greek, Armenian, Georgian, Tifinagh,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	292 and many others)
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	293 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	294 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	295 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	296 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	297 Emoji (including emoji modifier sequences, flag sequences,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	298 and ZWJ sequences)
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	299 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	300 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	301 </itemizedlist>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	302
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	303 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	304 In addition to OpenType shaping, HarfBuzz supports the latest
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	305 version of Graphite shaping (the "Graphite 2" model) and AAT
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	306 shaping.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	307 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	308
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	309 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	310 HarfBuzz can read and understand TrueType fonts (.ttf), TrueType
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	311 collections (.ttc), and OpenType fonts (.otf, including those
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	312 fonts that contain TrueType-style outlines and those that
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	313 contain PostScript CFF or CFF2 outlines).
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	314 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	315
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	316 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	317 HarfBuzz is designed and tested to run on top of the FreeType
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	318 font renderer. It can run on Linux, Android, Windows, macOS, and
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	319 iOS systems.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	320 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	321
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	322 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	323 In addition to its core shaping functionality, HarfBuzz provides
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	324 functions for accessing other font features, including optional
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	325 GSUB and GPOS OpenType features, as well as
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	326 all color-font formats (<literal>CBDT</literal>,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	327 <literal>sbix</literal>, <literal>COLR/CPAL</literal>, and
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	328 <literal>SVG-OT</literal>) and OpenType variable fonts. HarfBuzz
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	329 also includes a font-subsetting feature. HarfBuzz can perform
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	330 some low-level math-shaping operations, although it does not
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	331 currently perform full shaping for mathematical typesetting.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	332 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	333
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	334 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	335 A suite of command-line utilities is also provided in the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	336 source-code tree, designed to help users test and debug
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	337 HarfBuzz's features on real-world fonts and input.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	338 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	339 </section>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	340
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	341 <section id="what-harfbuzz-doesnt-do">
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	342 <title>What HarfBuzz doesn't do</title>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	343 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	344 HarfBuzz will take a Unicode string, shape it, and give you the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	345 information required to lay it out correctly on a single
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	346 horizontal (or vertical) line using the font provided. That is the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	347 extent of HarfBuzz's responsibility.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	348 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	349 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	350 It is important to note that if you are implementing a complete
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	351 text-layout engine you may have other responsibilities that
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	352 HarfBuzz will <emphasis>not</emphasis> help you with. For example:
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	353 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	354 <itemizedlist>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	355 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	356 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	357 HarfBuzz won't help you with bidirectionality. If you want to
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	358 lay out text that includes a mix of Hebrew and English, you
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	359 will need to ensure that each buffer provided to HarfBuzz
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	360 has all of its characters in the same order and that the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	361 directionality of the buffer is set correctly. This may mean
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	362 segmenting the text before it is placed into HarfBuzz buffers. In
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	363 other words, the user will hit the keys in the following
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	364 sequence:
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	365 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	366 <programlisting>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	367 A B C [space] ג ב א [space] D E F
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	368 </programlisting>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	369 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	370 but will expect to see in the output:
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	371 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	372 <programlisting>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	373 ABC אבג DEF
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	374 </programlisting>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	375 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	376 This reordering is called <emphasis>bidi processing</emphasis>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	377 ("bidi" is short for bidirectional), and there's an
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	378 algorithm as an annex to the Unicode Standard which tells you how
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	379 to process a string of mixed directionality.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	380 Before sending your string to HarfBuzz, you may need to apply the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	381 bidi algorithm to it. Libraries such as <ulink
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	382 url="http://icu-project.org/">ICU</ulink> and <ulink
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	383 url="http://fribidi.org/">fribidi</ulink> can do this for you.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	384 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	385 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	386 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	387 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	388 HarfBuzz won't help you with text that contains different font
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	389 properties. For instance, if you have the string "a
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	390 <emphasis>huge</emphasis> breakfast", and you expect
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	391 "huge" to be italic, then you will need to send three
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	392 strings to HarfBuzz: <literal>a</literal>, in your Roman font;
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	393 <literal>huge</literal> using your italic font; and
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	394 <literal>breakfast</literal> using your Roman font again.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	395 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	396 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	397 Similarly, if you change the font, font size, script,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	398 language, or direction within your string, then you will
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	399 need to shape each run independently and output them
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	400 independently. HarfBuzz expects to shape a run of characters
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	401 that all share the same properties.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	402 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	403 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	404 <listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	405 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	406 HarfBuzz won't help you with line breaking, hyphenation, or
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	407 justification. As mentioned above, HarfBuzz lays out the string
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	408 along a <emphasis>single line</emphasis> of, notionally,
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	409 infinite length. If you want to find out where the potential
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	410 word, sentence and line break points are in your text, you
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	411 could use the ICU library's break iterator functions.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	412 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	413 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	414 HarfBuzz can tell you how wide a shaped piece of text is, which is
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	415 useful input to a justification algorithm, but it knows nothing
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	416 about paragraphs, lines or line lengths. Nor will it adjust the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	417 space between words to fit them proportionally into a line.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	418 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	419 </listitem>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	420 </itemizedlist>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	421 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	422 As a layout-engine implementor, HarfBuzz will help you with the
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	423 interface between your text and your font, and that's something
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	424 that you'll need—what you then do with the glyphs that your font
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	425 returns is up to you.
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	426 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	427 </section>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	428
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	429 <section id="why-is-it-called-harfbuzz">
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	430 <title>Why is it called HarfBuzz?</title>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	431 <para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	432 HarfBuzz began its life as text-shaping code within the FreeType
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	433 project (and you will see references to the FreeType authors
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	434 within the source code copyright declarations), but was then
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	435 extracted out to its own project. This project is maintained by
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	436 Behdad Esfahbod, who named it HarfBuzz. Originally, it was a
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	437 shaping engine for OpenType fonts—"HarfBuzz" is
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	438 the Persian for "open type".
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	439 </para>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	440 </section>
b50eed0cc0ef ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. Franz Glasner <fzglas.hg@dom66.de> parents: diff changeset	441 </chapter>

Mercurial > hgrepos > Python2 > PyMuPDF

annotate mupdf-source/thirdparty/harfbuzz/docs/usermanual-what-is-harfbuzz.xml @ 22:d77477b4e151