forked from minhngoc25a/freetype2
83 lines
3.0 KiB
HTML
83 lines
3.0 KiB
HTML
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<head><title>The Design of FreeType 2 - Introduction</title>
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<basefont face="Georgia, Arial, Helvetica, Geneva">
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<style content="text/css">
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P { text-align=justify }
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H1 { text-align=center }
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H2 { text-align=center }
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LI { text-align=justify }
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</style>
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</head>
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<body text=#000000 bgcolor=#ffffff>
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<center><table width="500"><tr><td>
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<center><h1>The Design of FreeType 2</h1></center>
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<table width="100%" cellpadding=5><tr bgcolor="#ccccee"><td>
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<h1>Introduction</h1>
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</td></tr></table>
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<p>This document provides details on the design and implementation
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of the FreeType 2 library. Its goal is to allow developers to
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better understand the way FT2 is organized, in order to let them
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extend, customize and debug it.</p>
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<p>Before anything else, it is important to understand the <em>purpose</em>
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of this library, i.e. why it has been written:</p>
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<ul>
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<li><p>first of all, to allow client applications to <em>access font files
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easily</em>, wherever they could be stored, and as independently
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of font format as possible.</p></li>
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<li><p>to allow easy <em>retrieval of global font data</em> most commonly
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found in normal font formats (i.e. global metrics,
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encoding/charmaps, etc..)</p></li>
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<li><p>to allow easy <em>retrieval of individual glyph data</em>
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(metrics, images, name, anything else)</p></li>
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<li><p>to allow <em>access to font format-specific "features"</em>
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whenever possible (e.g. SFNT tables, Multiple Masters,
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OpenType Layout tables, etc..)</p></li>
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</ul>
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<p>its design has also severely been influenced by the following
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requirements:</p>
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<ul>
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<li><p><b>high portability</b>, as the library must be able to run
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on any kind of environment. this requirement introduces a few
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drastic choices that are part of FreeType 2's low-level system
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interface.</p></li>
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<li><p><b>extendibility</b>, as new features should be added with
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the least modifications in the library's code base. this
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requirements induces an extremely simple design where nearly
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all operations are provided by modules.
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</p></li>
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<li><p><b>customization</b>, it should be easy to build a version
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of the library that only contains the features needed by a
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specific project. This really is important when you need to
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integrate it in a font server for embedded graphics libraries.</p></li>
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<li><p><b>compactness</b> and <b>efficiency</b>, given that the
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primary target for this library is embedded systems with low
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cpu and memory resources.</p></li>
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</ul>
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<p>The rest of this document is divided in several sections. First, a
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few chapters will present the library's basic design as well as the
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objects/data managed internally by FreeType 2.</p>
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<p>A later section is then dedicated to library customization, relating
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such topics as system-specific interfaces, how to write your own
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module and how to tailor library initialisation & compilation
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to your needs.</p>
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</td></tr></table></center>
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</body>
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</html>
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