ref: 5330dd6e8131ebf9c9e910ecd522e7c2006bcdd7
parent: c9d7b5e3ed3cffc8bea6a140d8ae1f66397a9666
author: Werner Lemberg <[email protected]>
date: Thu Nov 9 01:26:30 EST 2000
Revised.
--- a/docs/glyphs/glyphs-1.html
+++ b/docs/glyphs/glyphs-1.html
@@ -1,12 +1,13 @@
-<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
+<!doctype html public "-//w3c//dtd html 4.0 transitional//en"
+ "http://www.w3.org/TR/REC-html40/loose.dtd">
<html>
<head>
- <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
- <meta name="Author" content="blob">
- <meta name="GENERATOR" content="Mozilla/4.5 [fr] (Win98; I) [Netscape]">
- <title>FreeType Glyph Conventions</title>
+ <meta http-equiv="Content-Type"
+ content="text/html; charset=iso-8859-1">
+ <meta name="Author"
+ content="David Turner">
+ <title>FreeType Glyph Conventions</title>
</head>
-<body>
<body text="#000000"
bgcolor="#FFFFFF"
@@ -14,156 +15,181 @@
vlink="#51188E"
alink="#FF0000">
-<center><h1>
-FreeType Glyph Conventions
-</h1></center>
+<h1 align=center>
+ FreeType Glyph Conventions
+</h1>
-<center><h2>
-version 2.1
-</h2></center>
-
-<center><h3>
-Copyright 1998-2000 David Turner (<a href="mailto:[email protected]">[email protected]</a>)<br>
-Copyright 2000 The FreeType Development Team (<a href="[email protected]">[email protected]</a>)
-</h3></center>
-
-<center><table width=650><tr><td>
-
-<center><table width="100%" border=0 cellpadding=5><tr bgcolor="#CCFFCC" valign=center>
-<td align=center width="30%">
-
-</td>
-<td align=center width="30%">
-<a href="index.html">Contents</a>
-</td>
-<td align=center width="30%">
-<a href="glyphs-2.html">Next</a>
-</td>
-</tr></table></center>
-
-<table width="100%" cellpadding=5><tr bgcolor="#CCCCFF" valign=center><td>
-<h2>
-I. Basic typographic concepts
+<h2 align=center>
+ Version 2.1
</h2>
-</td></tr></table>
-<a name="section-1"><h3>
-1. Font files, format and information
-</h3><blockquote>
+<h3 align=center>
+ Copyright 1998-2000 David Turner (<a
+ href="mailto:[email protected]">[email protected]</a>)<br>
+ Copyright 2000 The FreeType Development Team (<a
+ href="mailto:[email protected]">[email protected]</a>)
+</h3>
-<p>
-A font is a collection of various character images that can
-be used to display or print text. The images in a single font share some
-common properties, including look, style, serifs, etc.. Typographically
-speaking, one has to distinguish between a <b>font family</b> and its
-multiple <b>font faces</b>, which usually differ in style though come
-from the same template.</p>
+<center>
+<table width="65%">
+<tr><td>
-For example, "<i>Palatino Regular</i>" and "<i>Palatino Italic</i>" are
-two distinct <i>faces</i> from the same famous <i>family</i>, called
-"<i>Palatino</i>" itself.</p>
+ <center>
+ <table width="100%"
+ border=0
+ cellpadding=5>
+ <tr bgcolor="#CCFFCC"
+ valign=center>
+ <td align=center
+ width="30%">
+
+ </td>
+ <td align=center
+ width="30%">
+ <a href="index.html">Contents</a>
+ </td>
+ <td align=center
+ width="30%">
+ <a href="glyphs-2.html">Next</a>
+ </td>
+ </tr>
+ </table>
+ </center>
-<p>The single term font is nearly always used in ambiguous ways to refer
-to either a given family or given face, depending on the context. For example,
-most users of word-processors use "font" to describe a font family (e.g.
-Courier, Palatino, etc..); however most of these families are implemented
-through several data files depending on the file format : for TrueType,
-this is usually one per face (i.e. ARIAL.TFF for "Arial Regular", ARIALI.TTF
-for "Arial Italic", etc..). The file is also called a "font" but really
-contains a font face.
-</p>
+ <table width="100%">
+ <tr bgcolor="#CCCCFF"
+ valign=center><td>
+ <h2>
+ I. Basic typographic concepts
+ </h2>
+ </td></tr>
+ </table>
-<p>A <i>digital font</i> is thus a data file that may contain <i>one or
-more font faces</i>. For each of these, it contains character images,
-character metrics, as well as other kind of information important to the
-layout of text and the processing of specific character encodings. In some
-awkward formats, like Adobe Type1, a single font face is described through
-several files (i.e. one contains the character images, another one the
-character metrics). We will ignore this implementation issue in most of
-this document and consider digital fonts as single files, though FreeType
-2.0 is able to support multiple-files fonts correctly.
-</p>
+ <a name="section-1">
+ <h3>
+ 1. Font files, format and information
+ </h3>
-<p>As a convenience, a font file containing more than one face is called
-a font collection. This case is rather rare but can be seen in many asian
-fonts, which contain images for two or more scripts for a given language.
-</p>
+ <p>A font is a collection of various character images that can be used
+ to display or print text. The images in a single font share some common
+ properties, including look, style, serifs, etc. Typographically
+ speaking, one has to distinguish between a <em>font family</em> and its
+ multiple <em>font faces</em>, which usually differ in style though come
+ from the same template.</p>
+ For example, "Palatino Regular" and "Palatino Italic" are two distinct
+ <em>faces</em> from the same famous <em>family</em>, called "Palatino"
+ itself.</p>
+ <p>The single term <em>font</em> is nearly always used in ambiguous ways
+ to refer to either a given family or given face, depending on the
+ context. For example, most users of word-processors use "font" to
+ describe a font family (e.g. "Courier", "Palatino", etc.); however most
+ of these families are implemented through several data files depending
+ on the file format: For TrueType, this is usually one per face (i.e.
+ <tt>arial.ttf</tt> for "Arial Regular", <tt>ariali.ttf</tt> for "Arial
+ Italic", etc.). The file is also called a "font" but really contains a
+ font face.</p>
-</blockquote><h3><a name="section-2">
-2. Character images and mappings :
-</h3><blockquote>
+ <p>A <em>digital font</em> is thus a data file that may contain <em>one
+ or more font faces</em>. For each of these, it contains character
+ images, character metrics, as well as other kind of information
+ important to the layout of text and the processing of specific character
+ encodings. In some awkward formats, like Adobe's Type 1, a single
+ font face is described through several files (i.e. one contains the
+ character images, another one the character metrics). We will ignore
+ this implementation issue in most parts of this document and consider
+ digital fonts as single files, though FreeType 2.0 is able to
+ support multiple-files fonts correctly.</p>
+ <p>As a convenience, a font file containing more than one face is called
+ a <em>font collection</em>. This case is rather rare but can be seen in
+ many Asian fonts, which contain images for two or more representation
+ forms of a given scripts (usually for horizontal and vertical
+ layout.</p>
-<p>The character images are called <b>glyphs</b>. A single character
-can have several distinct images, i.e. several glyphs, depending on script,
-usage or context. Several characters can also take a single glyph (good
-examples are roman ligatures like "oe" and "fi" which can be represented
-by a single glyph). The relationships between characters
-and glyphs can be a very complex one but won't be detailed in this document.
-Moreover, some formats use more or less awkward schemes to store and access
-the glyphs. For the sake of clarity, we'll only retain the following notions
-when working with FreeType :</p>
+ <a name="section-2">
+ <h3>
+ 2. Character images and mappings
+ </h3>
-<ul>
-<p><li>
-A font file contains a set of glyphs, each one can be stored as a bitmap,
-a vector representation or any other scheme (e.g. most scalable formats
-use a combination of math representation and control data/programs). These
-glyphs can be stored in any order in the font file, and is typically accessed
-through a simple glyph index.
-</li></p>
+ <p>The character images are called <em>glyphs</em>. A single character
+ can have several distinct images, i.e. several glyphs, depending on
+ script, usage or context. Several characters can also take a single
+ glyph (good examples are Roman ligatures like "fi" and "fl" which can be
+ represented by a single glyph). The relationships between characters
+ and glyphs can be very complex, but won't be discussed in this document.
+ Moreover, some formats use more or less awkward schemes to store and
+ access glyphs. For the sake of clarity, we only retain the following
+ notions when working with FreeType:</p>
-<p><li>
-The font file contains one (or more) table, called a character map (or
-charmap in short), which is used to convert character codes for a given
-encoding (e.g. ASCII, Unicode, DBCS, Big5, etc..) into glyph indexes
-relative to the font file. A single font face may contain several charmaps.
-For example, most TrueType fonts contain an Apple-specific charmap as well
-as a Unicode charmap, which makes them usable on both Mac and Windows
-platforms.
-</li></p>
-</ul>
+ <ul>
+ <li>
+ <p>A font file contains a set of glyphs; each one can be stored as a
+ bitmap, a vector representation or any other scheme (most scalable
+ formats use a combination of mathematical representation and control
+ data/programs). These glyphs can be stored in any order in the font
+ file, and is typically accessed through a simple glyph index.</p>
+ </li>
+ <li>
+ <p>The font file contains one or more tables, called a <em>character
+ map</em> (or charmap in short), which is used to convert character
+ codes for a given encoding (e.g. ASCII, Unicode, DBCS, Big5, etc..)
+ into glyph indices relative to the font file. A single font face
+ may contain several charmaps. For example, most TrueType fonts
+ contain an Apple-specific charmap as well as a Unicode charmap,
+ which makes them usable on both Mac and Windows platforms.</p>
+ </li>
+ </ul>
+ <a name="section-3">
+ <h3>
+ 3. Character and font metrics
+ </h3>
-</blockquote><h3><a name="section-3">
-3. Character and font metrics :
-</h3><blockquote>
+ <p>Each glyph image is associated to various metrics which are used to
+ describe how must be placed and managed when rendering text. Though
+ they are described in more details in section III, they relate to
+ glyph placement, cursor advances as well as text layout. They are
+ extremely important to compute the flow of text when rendering a string
+ of text.</p>
-<p>Each glyph image is associated to various metrics which are used to
-describe the way it must be placed and managed when rendering text. Though
-they are described in more details in section III, they relate to glyph
-placement, cursor advances as well as text layouts. They are extremely
-important to compute the flow of text when rendering string of text.
-</p>
+ <p>Each scalable format also contains some global metrics, expressed in
+ notional units, to describe some properties of all glyphs in the same
+ face. Examples for global metrics are the maximum glyph bounding box,
+ the ascender, descender and text height for the font.</p>
-<p>Each scalable format also contains some global metrics, expressed in
-notional units, used to describe some properties of all glyphs in a same
-face. For example : the maximum glyph bounding box, the ascender, descender
-and text height for the font.
-</p>
+ <p>Though these metrics also exist for non-scalable formats, they only
+ apply for a set of given character dimensions and resolutions, and
+ they are usually expressed in pixels then.</p>
-<p>Though these metrics also exist for non-scalable formats, they only
-apply for a set of given character dimensions and resolutions, and they're
-usually expressed in pixels then.</p>
-<center><table width="100%" border=0 cellpadding=5><tr bgcolor="#CCFFCC" valign=center>
-<td align=center width="30%">
-
-</td>
-<td align=center width="30%">
-<a href="index.html">Contents</a>
-</td>
-<td align=center width="30%">
-<a href="glyphs-2.html">Next</a>
-</td>
-</tr></table></center>
+ <center>
+ <table width="100%"
+ border=0
+ cellpadding=5>
+ <tr bgcolor="#CCFFCC" valign=center>
+ <td align=center
+ width="30%">
+
+ </td>
+ <td align=center
+ width="30%">
+ <a href="index.html">Contents</a>
+ </td>
+ <td align=center
+ width="30%">
+ <a href="glyphs-2.html">Next</a>
+ </td>
+ </tr>
+ </table>
+ </center>
-</td></tr></table></center>
-
+</td></tr>
+</table>
+</center>
</body>
</html>