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<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="API documentation for the Rust `rusttype` crate."><meta name="keywords" content="rust, rustlang, rust-lang, rusttype"><title>rusttype - Rust</title><link rel="stylesheet" type="text/css" href="../normalize.css"><link rel="stylesheet" type="text/css" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../dark.css"><link rel="stylesheet" type="text/css" href="../light.css" id="themeStyle"><script src="../storage.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="shortcut icon" href="../favicon.ico"><style type="text/css">#crate-search{background-image:url("../down-arrow.svg");}</style></head><body class="rustdoc mod"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../rusttype/index.html'><div class='logo-container'><img src='../rust-logo.png' alt='logo'></div></a><p class='location'>Crate rusttype</p><div class="sidebar-elems"><a id='all-types' href='all.html'><p>See all rusttype's items</p></a><div class="block items"><ul><li><a href="#modules">Modules</a></li><li><a href="#structs">Structs</a></li><li><a href="#enums">Enums</a></li><li><a href="#traits">Traits</a></li><li><a href="#functions">Functions</a></li></ul></div><p class='location'></p><script>window.sidebarCurrent = {name: 'rusttype', ty: 'mod', relpath: '../'};</script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><a id="settings-menu" href="../settings.html"><img src="../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class='fqn'><span class='out-of-band'><span id='render-detail'><a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class='inner'>−</span>]</a></span><a class='srclink' href='../src/rusttype/lib.rs.html#1-1103' title='goto source code'>[src]</a></span><span class='in-band'>Crate <a class="mod" href=''>rusttype</a></span></h1><div class='docblock'><p>RustType is a pure Rust alternative to libraries like FreeType.</p>
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<p>The current capabilities of RustType:</p>
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<ul>
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<li>Reading TrueType formatted fonts and font collections. This includes
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<code>*.ttf</code> as well as a subset of <code>*.otf</code> font files.</li>
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<li>Retrieving glyph shapes and commonly used properties for a font and its
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glyphs.</li>
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<li>Laying out glyphs horizontally using horizontal and vertical metrics, and
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glyph-pair-specific kerning.</li>
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<li>Rasterising glyphs with sub-pixel positioning using an accurate analytical
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algorithm (not based on sampling).</li>
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<li>Managing a font cache on the GPU with the <code>gpu_cache</code> module. This keeps
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recently used glyph renderings in a dynamic cache in GPU memory to
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minimise texture uploads per-frame. It also allows you keep the draw call
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count for text very low, as all glyphs are kept in one GPU texture.</li>
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</ul>
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<p>Notable things that RustType does not support <em>yet</em>:</p>
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<ul>
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<li>OpenType formatted fonts that are not just TrueType fonts (OpenType is a
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superset of TrueType). Notably there is no support yet for cubic Bezier
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curves used in glyphs.</li>
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<li>Font hinting.</li>
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<li>Ligatures of any kind.</li>
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<li>Some less common TrueType sub-formats.</li>
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<li>Right-to-left and vertical text layout.</li>
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</ul>
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<h1 id="getting-started" class="section-header"><a href="#getting-started">Getting Started</a></h1>
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<p>To hit the ground running with RustType, look at the <code>simple.rs</code> example
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supplied with the crate. It demonstrates loading a font file, rasterising an
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arbitrary string, and displaying the result as ASCII art. If you prefer to
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just look at the documentation, the entry point for loading fonts is
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<code>FontCollection</code>, from which you can access individual fonts, then their
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glyphs.</p>
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<h1 id="glyphs" class="section-header"><a href="#glyphs">Glyphs</a></h1>
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<p>The glyph API uses wrapper structs to augment a glyph with information such
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as scaling and positioning, making relevant methods that make use of this
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information available as appropriate. For example, given a <code>Glyph</code> <code>glyph</code>
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obtained directly from a <code>Font</code>:</p>
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<div class="example-wrap"><pre class="rust rust-example-rendered">
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<span class="comment">// One of the few things you can do with an unsized, positionless glyph is get its id.</span>
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<span class="kw">let</span> <span class="ident">id</span> <span class="op">=</span> <span class="ident">glyph</span>.<span class="ident">id</span>();
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<span class="kw">let</span> <span class="ident">glyph</span> <span class="op">=</span> <span class="ident">glyph</span>.<span class="ident">scaled</span>(<span class="ident">Scale</span>::<span class="ident">uniform</span>(<span class="number">10.0</span>));
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<span class="comment">// Now glyph is a ScaledGlyph, you can do more with it, as well as what you can do with Glyph.</span>
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<span class="comment">// For example, you can access the correctly scaled horizontal metrics for the glyph.</span>
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<span class="kw">let</span> <span class="ident">h_metrics</span> <span class="op">=</span> <span class="ident">glyph</span>.<span class="ident">h_metrics</span>();
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<span class="kw">let</span> <span class="ident">glyph</span> <span class="op">=</span> <span class="ident">glyph</span>.<span class="ident">positioned</span>(<span class="ident">point</span>(<span class="number">5.0</span>, <span class="number">3.0</span>));
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<span class="comment">// Now glyph is a PositionedGlyph, and you can do even more with it, e.g. drawing.</span>
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<span class="ident">glyph</span>.<span class="ident">draw</span>(<span class="op">|</span><span class="ident">x</span>, <span class="ident">y</span>, <span class="ident">v</span><span class="op">|</span> {}); <span class="comment">// In this case the pixel values are not used.</span></pre></div>
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<h1 id="unicode-terminology" class="section-header"><a href="#unicode-terminology">Unicode terminology</a></h1>
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<p>This crate uses terminology for computerised typography as specified by the
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Unicode standard. If you are not sure of the differences between a code
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point, a character, and a glyph, you may want to check the <a href="http://unicode.org/glossary/">official Unicode
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glossary</a>, or alternatively, here's my take on
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it from a practical perspective:</p>
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<ul>
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<li>A character is what you would conventionally call a single symbol,
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independent of its appearance or representation in a particular font.
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Examples include <code>a</code>, <code>A</code>, <code>ä</code>, <code>å</code>, <code>1</code>, <code>*</code>, <code>Ω</code>, etc.</li>
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<li>A Unicode code point is the particular number that the Unicode standard
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associates with a particular character. Note however that code points also
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exist for things not conventionally thought of as characters by
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themselves, but can be combined to form characters, such as diacritics
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like accents. These "characters" are known in Unicode as "combining
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characters". E.g., a diaeresis (<code>¨</code>) has the code point U+0308. If this
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code point follows the code point U+0055 (the letter <code>u</code>), this sequence
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represents the character <code>ü</code>. Note that there is also a single codepoint
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for <code>ü</code>, U+00FC. This means that what visually looks like the same string
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can have multiple different Unicode representations. Some fonts will have
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glyphs (see below) for one sequence of codepoints, but not another that
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has the same meaning. To deal with this problem it is recommended to use
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Unicode normalisation, as provided by, for example, the
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<a href="http://crates.io/crates/unicode-normalization">unicode-normalization</a>
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crate, to convert to code point sequences that work with the font in
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question. Typically a font is more likely to support a single code point
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vs. a sequence with the same meaning, so the best normalisation to use is
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"canonical recomposition", known as NFC in the normalisation crate.</li>
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<li>A glyph is a particular font's shape to draw the character for a
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particular Unicode code point. This will have its own identifying number
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unique to the font, its ID.</li>
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</ul>
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</div><h2 id='modules' class='section-header'><a href="#modules">Modules</a></h2>
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<table><tr class='module-item'><td><a class="mod" href="gpu_cache/index.html" title='rusttype::gpu_cache mod'>gpu_cache</a></td><td class='docblock-short'><p>This module provides capabilities for managing a cache of rendered glyphs in
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GPU memory, with the goal of minimisng the size and frequency of glyph
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uploads to GPU memory from the CPU.</p>
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</td></tr></table><h2 id='structs' class='section-header'><a href="#structs">Structs</a></h2>
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<table><tr class='module-item'><td><a class="struct" href="struct.Codepoint.html" title='rusttype::Codepoint struct'>Codepoint</a></td><td class='docblock-short'><p>Represents a Unicode code point.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.Contour.html" title='rusttype::Contour struct'>Contour</a></td><td class='docblock-short'><p>A closed loop consisting of a sequence of <code>Segment</code>s.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.Curve.html" title='rusttype::Curve struct'>Curve</a></td><td class='docblock-short'><p>A quadratic Bezier curve, starting at <code>p[0]</code>, ending at <code>p[2]</code>, with control
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point <code>p[1]</code>.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.Font.html" title='rusttype::Font struct'>Font</a></td><td class='docblock-short'><p>A single font. This may or may not own the font data.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.FontCollection.html" title='rusttype::FontCollection struct'>FontCollection</a></td><td class='docblock-short'><p>A collection of fonts read straight from a font file's data. The data in the
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collection is not validated. This structure may or may not own the font
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data.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.Glyph.html" title='rusttype::Glyph struct'>Glyph</a></td><td class='docblock-short'><p>A single glyph of a font. this may either be a thin wrapper referring to the
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font and the glyph id, or it may be a standalone glyph that owns the data
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needed by it.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.GlyphId.html" title='rusttype::GlyphId struct'>GlyphId</a></td><td class='docblock-short'><p>Represents a glyph identifier for a particular font. This identifier will
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not necessarily correspond to the correct glyph in a font other than the
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one that it was obtained from.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.GlyphIter.html" title='rusttype::GlyphIter struct'>GlyphIter</a></td><td class='docblock-short'></td></tr><tr class='module-item'><td><a class="struct" href="struct.HMetrics.html" title='rusttype::HMetrics struct'>HMetrics</a></td><td class='docblock-short'><p>The "horizontal metrics" of a glyph. This is useful for calculating the
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horizontal offset of a glyph from the previous one in a string when laying a
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string out horizontally.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.IntoFontsIter.html" title='rusttype::IntoFontsIter struct'>IntoFontsIter</a></td><td class='docblock-short'></td></tr><tr class='module-item'><td><a class="struct" href="struct.LayoutIter.html" title='rusttype::LayoutIter struct'>LayoutIter</a></td><td class='docblock-short'></td></tr><tr class='module-item'><td><a class="struct" href="struct.Line.html" title='rusttype::Line struct'>Line</a></td><td class='docblock-short'><p>A straight line between two points, <code>p[0]</code> and <code>p[1]</code></p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.Point.html" title='rusttype::Point struct'>Point</a></td><td class='docblock-short'><p>A point in 2-dimensional space, with each dimension of type <code>N</code>.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.PositionedGlyph.html" title='rusttype::PositionedGlyph struct'>PositionedGlyph</a></td><td class='docblock-short'><p>A glyph augmented with positioning and scaling information. You can query
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such a glyph for information that depends on the scale and position of the
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glyph.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.Rect.html" title='rusttype::Rect struct'>Rect</a></td><td class='docblock-short'><p>A rectangle, with top-left corner at <code>min</code>, and bottom-right corner at
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<code>max</code>.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.Scale.html" title='rusttype::Scale struct'>Scale</a></td><td class='docblock-short'><p>Defines the size of a rendered face of a font, in pixels, horizontally and
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vertically. A vertical scale of <code>y</code> pixels means that the distance betwen
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the ascent and descent lines (see <code>VMetrics</code>) of the face will be <code>y</code>
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pixels. If <code>x</code> and <code>y</code> are equal the scaling is uniform. Non-uniform scaling
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by a factor <em>f</em> in the horizontal direction is achieved by setting <code>x</code> equal
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to <em>f</em> times <code>y</code>.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.ScaledGlyph.html" title='rusttype::ScaledGlyph struct'>ScaledGlyph</a></td><td class='docblock-short'><p>A glyph augmented with scaling information. You can query such a glyph for
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information that depends on the scale of the glyph.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.SharedGlyphData.html" title='rusttype::SharedGlyphData struct'>SharedGlyphData</a></td><td class='docblock-short'></td></tr><tr class='module-item'><td><a class="struct" href="struct.VMetrics.html" title='rusttype::VMetrics struct'>VMetrics</a></td><td class='docblock-short'><p>The "vertical metrics" of a font at a particular scale. This is useful for
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calculating the amount of vertical space to give a line of text, and for
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computing the vertical offset between successive lines.</p>
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</td></tr><tr class='module-item'><td><a class="struct" href="struct.Vector.html" title='rusttype::Vector struct'>Vector</a></td><td class='docblock-short'><p>A vector in 2-dimensional space, with each dimension of type <code>N</code>.</p>
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</td></tr></table><h2 id='enums' class='section-header'><a href="#enums">Enums</a></h2>
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<table><tr class='module-item'><td><a class="enum" href="enum.Error.html" title='rusttype::Error enum'>Error</a></td><td class='docblock-short'><p>The type for errors returned by rusttype.</p>
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</td></tr><tr class='module-item'><td><a class="enum" href="enum.Segment.html" title='rusttype::Segment enum'>Segment</a></td><td class='docblock-short'><p>Part of a <code>Contour</code>, either a <code>Line</code> or a <code>Curve</code>.</p>
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</td></tr><tr class='module-item'><td><a class="enum" href="enum.SharedBytes.html" title='rusttype::SharedBytes enum'>SharedBytes</a></td><td class='docblock-short'><p><code>SharedBytes</code> handles the lifetime of font data used in RustType. The data
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is either a shared reference to externally owned data, or managed by
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reference counting. <code>SharedBytes</code> can be conveniently used with <code>From</code> and
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<code>Into</code>, and dereferences to the contained bytes.</p>
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</td></tr></table><h2 id='traits' class='section-header'><a href="#traits">Traits</a></h2>
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<table><tr class='module-item'><td><a class="trait" href="trait.IntoGlyphId.html" title='rusttype::IntoGlyphId trait'>IntoGlyphId</a></td><td class='docblock-short'><p>A trait for types that can be converted into a <code>GlyphId</code>, in the context of
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a specific font.</p>
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</td></tr></table><h2 id='functions' class='section-header'><a href="#functions">Functions</a></h2>
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<table><tr class='module-item'><td><a class="fn" href="fn.point.html" title='rusttype::point fn'>point</a></td><td class='docblock-short'><p>A convenience function for generating <code>Point</code>s.</p>
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</td></tr><tr class='module-item'><td><a class="fn" href="fn.vector.html" title='rusttype::vector fn'>vector</a></td><td class='docblock-short'><p>A convenience function for generating <code>Vector</code>s.</p>
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</td></tr></table></section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>⏎</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g., <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g., <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g., <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../";window.currentCrate = "rusttype";</script><script src="../aliases.js"></script><script src="../main.js"></script><script defer src="../search-index.js"></script></body></html> |
