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<head><title>The Design of FreeType 2 - Introduction</title>
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<center><h1>The Design of FreeType 2</h1></center>
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<h1>Introduction</h1>
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<p>This document provides details on the design and implementation
of the FreeType 2 library. Its goal is to allow developers to
better understand the way FT2 is organized, in order to let them
extend, customize and debug it.</p>
<p>Before anything else, it is important to understand the <em>purpose</em>
of this library, i.e. why it has been written:</p>
<ul>
<li><p>first of all, to allow client applications to <em>access font files
easily</em>, wherever they could be stored, and as independently
of font format as possible.</p></li>
<li><p>to allow easy <em>retrieval of global font data</em> most commonly
found in normal font formats (i.e. global metrics,
encoding/charmaps, etc..)</p></li>
<li><p>to allow easy <em>retrieval of individual glyph data</em>
(metrics, images, name, anything else)</p></li>
<li><p>to allow <em>access to font format-specific "features"</em>
whenever possible (e.g. SFNT tables, Multiple Masters,
OpenType Layout tables, etc..)</p></li>
</ul>
<p>its design has also severely been influenced by the following
requirements:</p>
<ul>
<li><p><b>high portability</b>, as the library must be able to run
on any kind of environment. this requirement introduces a few
drastic choices that are part of FreeType 2's low-level system
interface.</p></li>
<li><p><b>extendibility</b>, as new features should be added with
the least modifications in the library's code base. this
requirements induces an extremely simple design where nearly
all operations are provided by modules.
</p></li>
<li><p><b>customization</b>, it should be easy to build a version
of the library that only contains the features needed by a
specific project. This really is important when you need to
integrate it in a font server for embedded graphics libraries.</p></li>
<li><p><b>compactness</b> and <b>efficiency</b>, given that the
primary target for this library is embedded systems with low
cpu and memory resources.</p></li>
</ul>
<p>The rest of this document is divided in several sections. First, a
few chapters will present the library's basic design as well as the
objects/data managed internally by FreeType 2.</p>
<p>A later section is then dedicated to library customization, relating
such topics as system-specific interfaces, how to write your own
module and how to tailor library initialisation & compilation
to your needs.</p>
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