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author | Simon Cozens <simon@simon-cozens.org> | 2015-08-29 08:21:18 +0100 |
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committer | Simon Cozens <simon@simon-cozens.org> | 2015-08-29 08:21:18 +0100 |
commit | 5470e744dd264c2dc33437a68d20bcf7c5ffb905 (patch) | |
tree | f290158b8722b73d9215d8ef22f8c413d507f188 /docs/usermanual-ch03.xml | |
parent | f0807654da160bd7ceb9aff5b8338ec0b643171c (diff) |
Current state and skeleton outline
Diffstat (limited to 'docs/usermanual-ch03.xml')
-rw-r--r-- | docs/usermanual-ch03.xml | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/docs/usermanual-ch03.xml b/docs/usermanual-ch03.xml new file mode 100644 index 00000000..66ec0a88 --- /dev/null +++ b/docs/usermanual-ch03.xml @@ -0,0 +1,77 @@ +<sect1 id="buffers-language-script-and-direction"> + <title>Buffers, language, script and direction</title> + <para> + The input to Harfbuzz is a series of Unicode characters, stored in a + buffer. In this chapter, we'll look at how to set up a buffer with + the text that we want and then customize the properties of the + buffer. + </para> + <sect2 id="creating-and-destroying-buffers"> + <title>Creating and destroying buffers</title> + <para> + As we saw in our initial example, a buffer is created and + initialized with <literal>hb_buffer_create()</literal>. This + produces a new, empty buffer object, instantiated with some + default values and ready to accept your Unicode strings. + </para> + <para> + Harfbuzz manages the memory of objects that it creates (such as + buffers), so you don't have to. When you have finished working on + a buffer, you can call <literal>hb_buffer_destroy()</literal>: + </para> + <programlisting language="C"> + hb_buffer_t *buffer = hb_buffer_create(); + ... + hb_buffer_destroy(buffer); +</programlisting> + <para> + This will destroy the object and free its associated memory - + unless some other part of the program holds a reference to this + buffer. If you acquire a Harfbuzz buffer from another subsystem + and want to ensure that it is not garbage collected by someone + else destroying it, you should increase its reference count: + </para> + <programlisting language="C"> +void somefunc(hb_buffer_t *buffer) { + buffer = hb_buffer_reference(buffer); + ... +</programlisting> + <para> + And then decrease it once you're done with it: + </para> + <programlisting language="C"> + hb_buffer_destroy(buffer); +} +</programlisting> + <para> + To throw away all the data in your buffer and start from scratch, + call <literal>hb_buffer_reset(buffer)</literal>. If you want to + throw away the string in the buffer but keep the options, you can + instead call <literal>hb_buffer_clear_contents(buffer)</literal>. + </para> + </sect2> + <sect2 id="adding-text-to-the-buffer"> + <title>Adding text to the buffer</title> + <para> + Now we have a brand new Harfbuzz buffer. Let's start filling it + with text! From Harfbuzz's perspective, a buffer is just a stream + of Unicode codepoints, but your input string is probably in one of + the standard Unicode character encodings (UTF-8, UTF-16, UTF-3 ) + </para> + </sect2> + <sect2 id="setting-buffer-properties"> + <title>Setting buffer properties</title> + <para> + </para> + </sect2> + <sect2 id="what-about-the-other-scripts"> + <title>What about the other scripts?</title> + <para> + </para> + </sect2> + <sect2 id="customizing-unicode-functions"> + <title>Customizing Unicode functions</title> + <para> + </para> + </sect2> +</sect1>
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