Usermanual; minor wording changes.
This commit is contained in:
Nathan Willis
Khaled Hosny
parent
e89f43dc08
commit
01400f7425
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@ -18,9 +18,7 @@
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properties that affect shaping. The most important are the
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text-flow direction (e.g., left-to-right, right-to-left,
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top-to-bottom, or bottom-to-top), the script tag, and the
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language tag. HarfBuzz can attempt to guess the correct values
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for the buffer based on its contents if you do not set them
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explicitly.
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language tag.
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</para>
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<para>
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@ -29,7 +27,8 @@
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indicate whether or not to visibly render Unicode <literal>Default
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Ignorable</literal> codepoints, and to modify the cluster-merging
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behavior for the buffer. For shaped output buffers, the
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individual X and Y offsets and widths of each glyph are
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individual X and Y offsets and <literal>advances</literal>
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(the logical dimensions) of each glyph are
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accessible. HarfBuzz also flags glyphs as
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<literal>UNSAFE_TO_BREAK</literal> if breaking the string at
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that glyph (e.g., in a line-breaking or hyphenation process)
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@ -61,9 +60,10 @@
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</para>
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<para>
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HarfBuzz provides glue code to integrate with FreeType, GObject,
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Uniscribe, and CoreText. Support for integrating with
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DirectWrite is experimental at present.
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HarfBuzz provides glue code to integrate with various other
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libraries, including FreeType, GObject, and CoreText. Support
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for integrating with Uniscribe and DirectWrite is experimental
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at present.
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</para>
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</section>
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@ -279,7 +279,11 @@
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graphics-rendering library. The default setting is to
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check for the presence of Cairo and, if it is found,
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build with Cairo support.
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</para>
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</para>
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<para>
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Note: Cairo is used only by the HarfBuzz
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command-line utilities, and not by the HarfBuzz library.
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</para>
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</listitem>
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</varlistentry>
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@ -296,6 +300,10 @@
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is to check for the presence of Fontconfig and, if it is
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found, build with Fontconfig support.
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</para>
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<para>
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Note: Fontconfig is used only by the HarfBuzz
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command-line utilities, and not by the HarfBuzz library.
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</para>
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</listitem>
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</varlistentry>
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@ -296,10 +296,7 @@
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<para>
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In addition to OpenType shaping, HarfBuzz supports the latest
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version of Graphite shaping. HarfBuzz currently supports AAT
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shaping only on macOS and iOS systems, and in a pass-through
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fashion: HarfBuzz hands off AAT support to the system CoreText
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library. However, full, built-in AAT support within HarfBuzz is
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under development.
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shaping only on macOS and iOS systems.
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</para>
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<para>
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@ -321,13 +318,9 @@
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all color-font formats (<literal>CBDT</literal>,
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<literal>sbix</literal>, <literal>COLR/CPAL</literal>, and
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<literal>SVG-OT</literal>) and OpenType variable fonts. HarfBuzz
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also includes a font-subsetting feature.
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</para>
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<para>
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HarfBuzz can perform some low-level math-shaping operations,
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although it does not currently perform full shaping for
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mathematical typesetting.
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also includes a font-subsetting feature. HarfBuzz can perform
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some low-level math-shaping operations, although it does not
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currently perform full shaping for mathematical typesetting.
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</para>
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<para>
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@ -355,9 +348,10 @@
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<para>
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HarfBuzz won't help you with bidirectionality. If you want to
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lay out text that includes a mix of Hebrew and English, you
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will need to ensure that each buffer provided to HarfBuzz has its
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characters in the correct layout order. This will be different
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from the logical order in which the Unicode text is stored. In
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will need to ensure that each buffer provided to HarfBuzz
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has all of its characters in the same order and that the
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directionality of the buffer is set correctly. This may mean
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segmenting the text before it is placed into HarfBuzz buffers. In
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other words, the user will hit the keys in the following
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sequence:
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</para>
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@ -374,7 +368,7 @@
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This reordering is called <emphasis>bidi processing</emphasis>
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("bidi" is short for bidirectional), and there's an
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algorithm as an annex to the Unicode Standard which tells you how
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to reorder a string from logical order into presentation order.
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to process a string of mixed directionality.
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Before sending your string to HarfBuzz, you may need to apply the
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bidi algorithm to it. Libraries such as <ulink
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url="http://icu-project.org/">ICU</ulink> and <ulink
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@ -412,12 +406,7 @@
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HarfBuzz can tell you how wide a shaped piece of text is, which is
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useful input to a justification algorithm, but it knows nothing
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about paragraphs, lines or line lengths. Nor will it adjust the
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space between words to fit them proportionally into a line. If you
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want to layout text in paragraphs, you will probably want to send
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each word of your text to HarfBuzz to determine its shaped width
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after glyph substitutions, then work out how many words will fit
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on a line, and then finally output each word of the line separated
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by a space of the correct size to fully justify the paragraph.
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space between words to fit them proportionally into a line.
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</para>
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</listitem>
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</itemizedlist>
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