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| <section id="nx-fonts-support-nxfonts"> |
| <h1>NX Fonts Support (<code class="docutils literal notranslate"><span class="pre">NXFONTS</span></code>)<a class="headerlink" href="#nx-fonts-support-nxfonts" title="Permalink to this heading"></a></h1> |
| <section id="nxfonts-types"> |
| <h2>NXFONTS types<a class="headerlink" href="#nxfonts-types" title="Permalink to this heading"></a></h2> |
| <dl class="c struct"> |
| <dt class="sig sig-object c" id="c.nx_fontmetric_s"> |
| <span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nx_fontmetric_s</span></span></span><a class="headerlink" href="#c.nx_fontmetric_s" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>This structures provides the metrics for one glyph:</p> |
| <div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="k">struct</span><span class="w"> </span><span class="nc">nx_fontmetric_s</span> |
| <span class="p">{</span> |
| <span class="w"> </span><span class="kt">uint32_t</span><span class="w"> </span><span class="n">stride</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Width of one font row in bytes */</span> |
| <span class="w"> </span><span class="kt">uint32_t</span><span class="w"> </span><span class="n">width</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="mi">6</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Width of the font in bits */</span> |
| <span class="w"> </span><span class="kt">uint32_t</span><span class="w"> </span><span class="n">height</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="mi">6</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Height of the font in rows */</span> |
| <span class="w"> </span><span class="kt">uint32_t</span><span class="w"> </span><span class="n">xoffset</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="mi">6</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Top, left-hand corner X-offset in pixels */</span> |
| <span class="w"> </span><span class="kt">uint32_t</span><span class="w"> </span><span class="n">yoffset</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="mi">6</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Top, left-hand corner y-offset in pixels */</span> |
| <span class="w"> </span><span class="kt">uint32_t</span><span class="w"> </span><span class="n">unused</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="mi">6</span><span class="p">;</span> |
| <span class="p">};</span> |
| </pre></div> |
| </div> |
| </dd></dl> |
| |
| <dl class="c struct"> |
| <dt class="sig sig-object c" id="c.nx_fontbitmap_s"> |
| <span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nx_fontbitmap_s</span></span></span><a class="headerlink" href="#c.nx_fontbitmap_s" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>This structure binds the glyph metrics to the glyph bitmap:</p> |
| <div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="k">struct</span><span class="w"> </span><span class="nc">nx_fontbitmap_s</span> |
| <span class="p">{</span> |
| <span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="nc">nx_fontmetric_s</span><span class="w"> </span><span class="n">metric</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Character metrics */</span> |
| <span class="w"> </span><span class="n">FAR</span><span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">uint8_t</span><span class="w"> </span><span class="o">*</span><span class="n">bitmap</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Pointer to the character bitmap */</span> |
| <span class="p">};</span> |
| </pre></div> |
| </div> |
| </dd></dl> |
| |
| <dl class="c struct"> |
| <dt class="sig sig-object c" id="c.nx_fontset_s"> |
| <span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nx_fontset_s</span></span></span><a class="headerlink" href="#c.nx_fontset_s" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>This structure describes one contiguous grouping of glyphs that can be |
| described by an array starting with encoding <code class="docutils literal notranslate"><span class="pre">first</span></code> and extending |
| through (<code class="docutils literal notranslate"><span class="pre">first</span></code> + <code class="docutils literal notranslate"><span class="pre">nchars</span></code> - 1).</p> |
| <div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="k">struct</span><span class="w"> </span><span class="nc">nx_fontset_s</span> |
| <span class="p">{</span> |
| <span class="w"> </span><span class="kt">uint8_t</span><span class="w"> </span><span class="n">first</span><span class="p">;</span><span class="w"> </span><span class="cm">/* First bitmap character code */</span> |
| <span class="w"> </span><span class="kt">uint8_t</span><span class="w"> </span><span class="n">nchars</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Number of bitmap character codes */</span> |
| <span class="w"> </span><span class="n">FAR</span><span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="nc">nx_fontbitmap_s</span><span class="w"> </span><span class="o">*</span><span class="n">bitmap</span><span class="p">;</span> |
| <span class="p">};</span> |
| </pre></div> |
| </div> |
| </dd></dl> |
| |
| <dl class="c struct"> |
| <dt class="sig sig-object c" id="c.nx_font_s"> |
| <span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nx_font_s</span></span></span><a class="headerlink" href="#c.nx_font_s" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>This structure describes the overall fontset.</p> |
| <div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="k">struct</span><span class="w"> </span><span class="nc">nx_font_s</span> |
| <span class="p">{</span> |
| <span class="w"> </span><span class="kt">uint8_t</span><span class="w"> </span><span class="n">mxheight</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Max height of one glyph in rows */</span> |
| <span class="w"> </span><span class="kt">uint8_t</span><span class="w"> </span><span class="n">mxwidth</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Max width of any glyph in pixels */</span> |
| <span class="w"> </span><span class="kt">uint8_t</span><span class="w"> </span><span class="n">mxbits</span><span class="p">;</span><span class="w"> </span><span class="cm">/* Max number of bits per character code */</span> |
| <span class="w"> </span><span class="kt">uint8_t</span><span class="w"> </span><span class="n">spwidth</span><span class="p">;</span><span class="w"> </span><span class="cm">/* The width of a space in pixels */</span> |
| <span class="p">};</span> |
| </pre></div> |
| </div> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.nxf_getfonthandle"> |
| <a class="reference internal" href="nx.html#c.NXHANDLE" title="NXHANDLE"><span class="n"><span class="pre">NXHANDLE</span></span></a><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nxf_getfonthandle</span></span></span><span class="sig-paren">(</span><span class="k"><span class="pre">enum</span></span><span class="w"> </span><span class="n"><span class="pre">nx_fontid_e</span></span><span class="w"> </span><span class="n"><span class="pre">fontid</span></span><span class="sig-paren">)</span><span class="p"><span class="pre">;</span></span><a class="headerlink" href="#c.nxf_getfonthandle" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Given a numeric font ID, return a handle that may be |
| subsequently be used to access the font data sets.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>fontid</strong> – Identifies the font set to use</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>A handle that may be subsequently be used to access the font data sets.</p> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.nxf_getfontset"> |
| <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.nx_font_s" title="nx_font_s"><span class="n"><span class="pre">nx_font_s</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">nxf_getfontset</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="nx.html#c.NXHANDLE" title="NXHANDLE"><span class="n"><span class="pre">NXHANDLE</span></span></a><span class="w"> </span><span class="n"><span class="pre">handle</span></span><span class="sig-paren">)</span><span class="p"><span class="pre">;</span></span><a class="headerlink" href="#c.nxf_getfontset" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Return information about the current font set.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>handle</strong> – A font handle previously returned by <a class="reference internal" href="#c.nxf_getfonthandle" title="nxf_getfonthandle"><code class="xref c c-func docutils literal notranslate"><span class="pre">nxf_getfonthandle()</span></code></a>.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>An instance of <code class="docutils literal notranslate"><span class="pre">struct</span> <span class="pre">nx_font_s</span></code> describing the font set.</p> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.nxf_getbitmap"> |
| <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.nx_fontbitmap_s" title="nx_fontbitmap_s"><span class="n"><span class="pre">nx_fontbitmap_s</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">nxf_getbitmap</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="nx.html#c.NXHANDLE" title="NXHANDLE"><span class="n"><span class="pre">NXHANDLE</span></span></a><span class="w"> </span><span class="n"><span class="pre">handle</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">ch</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.nxf_getbitmap" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Return font bitmap information for the selected |
| character encoding.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>ch</strong> – The char code for the requested bitmap.</p></li> |
| <li><p><strong>handle</strong> – A font handle previously returned by <a class="reference internal" href="#c.nxf_getfonthandle" title="nxf_getfonthandle"><code class="xref c c-func docutils literal notranslate"><span class="pre">nxf_getfonthandle()</span></code></a>.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>An instance of <a class="reference internal" href="#c.nx_fontbitmap_s" title="nx_fontbitmap_s"><code class="xref c c-struct docutils literal notranslate"><span class="pre">nx_fontbitmap_s</span></code></a> describing the glyph.</p> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.nxf_convert_2bpp"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nxf_convert_2bpp</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="n"><span class="pre">uint8_t</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">dest</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">height</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">width</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">stride</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.nx_fontbitmap_s" title="nx_fontbitmap_s"><span class="n"><span class="pre">nx_fontbitmap_s</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">bm</span></span>, <a class="reference internal" href="nxgl.html#c.nxgl_mxpixel_t" title="nxgl_mxpixel_t"><span class="n"><span class="pre">nxgl_mxpixel_t</span></span></a><span class="w"> </span><span class="n"><span class="pre">color</span></span><span class="sig-paren">)</span><span class="p"><span class="pre">;</span></span><a class="headerlink" href="#c.nxf_convert_2bpp" title="Permalink to this definition"></a><br /></dt> |
| <dd></dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.nxf_convert_4bpp"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nxf_convert_4bpp</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="n"><span class="pre">uint8_t</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">dest</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">height</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">width</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">stride</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.nx_fontbitmap_s" title="nx_fontbitmap_s"><span class="n"><span class="pre">nx_fontbitmap_s</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">bm</span></span>, <a class="reference internal" href="nxgl.html#c.nxgl_mxpixel_t" title="nxgl_mxpixel_t"><span class="n"><span class="pre">nxgl_mxpixel_t</span></span></a><span class="w"> </span><span class="n"><span class="pre">color</span></span><span class="sig-paren">)</span><span class="p"><span class="pre">;</span></span><a class="headerlink" href="#c.nxf_convert_4bpp" title="Permalink to this definition"></a><br /></dt> |
| <dd></dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.nxf_convert_8bpp"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nxf_convert_8bpp</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="n"><span class="pre">uint8_t</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">dest</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">height</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">width</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">stride</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.nx_fontbitmap_s" title="nx_fontbitmap_s"><span class="n"><span class="pre">nx_fontbitmap_s</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">bm</span></span>, <a class="reference internal" href="nxgl.html#c.nxgl_mxpixel_t" title="nxgl_mxpixel_t"><span class="n"><span class="pre">nxgl_mxpixel_t</span></span></a><span class="w"> </span><span class="n"><span class="pre">color</span></span><span class="sig-paren">)</span><span class="p"><span class="pre">;</span></span><a class="headerlink" href="#c.nxf_convert_8bpp" title="Permalink to this definition"></a><br /></dt> |
| <dd></dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.nxf_convert_16bpp"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nxf_convert_16bpp</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">dest</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">height</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">width</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">stride</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.nx_fontbitmap_s" title="nx_fontbitmap_s"><span class="n"><span class="pre">nx_fontbitmap_s</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">bm</span></span>, <a class="reference internal" href="nxgl.html#c.nxgl_mxpixel_t" title="nxgl_mxpixel_t"><span class="n"><span class="pre">nxgl_mxpixel_t</span></span></a><span class="w"> </span><span class="n"><span class="pre">color</span></span><span class="sig-paren">)</span><span class="p"><span class="pre">;</span></span><a class="headerlink" href="#c.nxf_convert_16bpp" title="Permalink to this definition"></a><br /></dt> |
| <dd></dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.nxf_convert_24bpp"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nxf_convert_24bpp</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="n"><span class="pre">uint32_t</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">dest</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">height</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">width</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">stride</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.nx_fontbitmap_s" title="nx_fontbitmap_s"><span class="n"><span class="pre">nx_fontbitmap_s</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">bm</span></span>, <a class="reference internal" href="nxgl.html#c.nxgl_mxpixel_t" title="nxgl_mxpixel_t"><span class="n"><span class="pre">nxgl_mxpixel_t</span></span></a><span class="w"> </span><span class="n"><span class="pre">color</span></span><span class="sig-paren">)</span><span class="p"><span class="pre">;</span></span><a class="headerlink" href="#c.nxf_convert_24bpp" title="Permalink to this definition"></a><br /></dt> |
| <dd></dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.nxf_convert_32bpp"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">nxf_convert_32bpp</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="n"><span class="pre">uint32_t</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">dest</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">height</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">width</span></span>, <span class="n"><span class="pre">uint16_t</span></span><span class="w"> </span><span class="n"><span class="pre">stride</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.nx_fontbitmap_s" title="nx_fontbitmap_s"><span class="n"><span class="pre">nx_fontbitmap_s</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">bm</span></span>, <a class="reference internal" href="nxgl.html#c.nxgl_mxpixel_t" title="nxgl_mxpixel_t"><span class="n"><span class="pre">nxgl_mxpixel_t</span></span></a><span class="w"> </span><span class="n"><span class="pre">color</span></span><span class="sig-paren">)</span><span class="p"><span class="pre">;</span></span><a class="headerlink" href="#c.nxf_convert_32bpp" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Convert the 1BPP font to a new pixel depth.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>dest</strong> – The destination buffer provided by the caller.</p></li> |
| <li><p><strong>height</strong> – The max height of the returned char in rows.</p></li> |
| <li><p><strong>width</strong> – The max width of the returned char in pixels.</p></li> |
| <li><p><strong>stride</strong> – The width of the destination buffer in bytes.</p></li> |
| <li><p><strong>bm</strong> – Describes the character glyph to convert</p></li> |
| <li><p><strong>color</strong> – The color to use for ‘1’ bits in the font bitmap (0 bits are transparent).</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p><code class="docutils literal notranslate"><span class="pre">OK</span></code> on success; <code class="docutils literal notranslate"><span class="pre">ERROR</span></code> on failure with <code class="docutils literal notranslate"><span class="pre">errno</span></code> set appropriately.</p> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| </section> |
| <section id="wide-font-support"> |
| <h2>Wide Font Support<a class="headerlink" href="#wide-font-support" title="Permalink to this heading"></a></h2> |
| <p>Question:</p> |
| <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>> My team is trying the nuttx graphics with chinese fonts, but nx seems not |
| > support fonts quantity more than 256 chars, right? |
| </pre></div> |
| </div> |
| <p>Answer:</p> |
| <div class="highlight-none notranslate"><div class="highlight"><pre><span></span>NuttX currently only uses fonts with 7-bit and 8-bit character sets. But |
| I believe that that limitation is mostly arbitrary. It should be a simple |
| extension to the font subsystem to use 16-bit fonts. |
| </pre></div> |
| </div> |
| <section id="adding-16-bit-font-support"> |
| <h3>Adding 16-Bit Font support<a class="headerlink" href="#adding-16-bit-font-support" title="Permalink to this heading"></a></h3> |
| <section id="current-7-8-bit-font-implementation"> |
| <h4>Current 7/8-bit Font Implementation<a class="headerlink" href="#current-7-8-bit-font-implementation" title="Permalink to this heading"></a></h4> |
| <p>All of critical font interfaces allow for 16-bit character sets:</p> |
| <div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="n">FAR</span><span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="nc">nx_fontbitmap_s</span><span class="w"> </span><span class="o">*</span><span class="n">nxf_getbitmap</span><span class="p">(</span><span class="n">NXHANDLE</span><span class="w"> </span><span class="n">handle</span><span class="p">,</span><span class="w"> </span><span class="kt">uint16_t</span><span class="w"> </span><span class="n">ch</span><span class="p">)</span> |
| </pre></div> |
| </div> |
| <p>The character code is only used to look-up of a glyph in a table. There is a |
| definition that controls the width of the character set: CONFIG_NXFONTS_CHARBITS. |
| This currently defaults to 7 but all existing fonts support 8-bits.</p> |
| <p>My first guess is that the only thing that would have to change is that single |
| file nxfonts_bitmaps.c (and the function nxf_getglyphset() in the file |
| nxfonts_getfont.c) . nxfonts_bitmaps.c is used to auto-generate 7/8-bit font |
| data sents. Here is how that works:</p> |
| <ul class="simple"> |
| <li><p>Each 7-8 bit file is described by a header file like, for example, |
| nxfonts_sans17x22.h.</p></li> |
| <li><p>At build time each of these header files is used to create a C file, |
| like, nxfonts_bitmaps_sans17x22.c.</p></li> |
| <li><p>It creates the C file (like nxfonts_bitmaps_sans17x22.c) by compiling |
| nxfonts_bitmaps.c and including nxfonts_sans17x22.h to create the font |
| dataset at build time.</p></li> |
| </ul> |
| <p>The function nxf_getglyphset() in the file nxfonts_getfont.c selects the 7-bit |
| font range (codes < 128) or the 8-bit range (code >= 128 > 256). The fonts are |
| kept in simple arrays splitting the data up into ranges of values lets you above |
| the non-printable codes at the beginning and end of each range. There is even a |
| comment in the code there “Someday, perhaps 16-bit fonts will go here”.</p> |
| </section> |
| <section id="adding-wide-fonts"> |
| <h4>Adding Wide Fonts<a class="headerlink" href="#adding-wide-fonts" title="Permalink to this heading"></a></h4> |
| <p>To add a single wide font, the easiest way would be to simply add the final |
| .C file without going through the C auto-generation step. That should be VERY |
| easy. (But since it has never been used with larger character sets, I am sure |
| that there are bugs and things that need to be fixed).</p> |
| <p>If you want to add many wide fonts, then perhaps you would have to create a new |
| version of the C auto-generation logic. That would require more effort.</p> |
| <p>I am willing to help and advise. Having good wide character support in the NuttX |
| graphics would be an important improvement to NuttX. This is not a lot of code |
| nor is it very difficult code so you should not let it be an obstacle for you.</p> |
| </section> |
| </section> |
| <section id="font-storage-issues"> |
| <h3>Font Storage Issues<a class="headerlink" href="#font-storage-issues" title="Permalink to this heading"></a></h3> |
| <p>One potential problem may be the amount of memory required by fonts with |
| thousands of characters. If you have a lot of flash, it may not be a problem, |
| but on many microcontrollers it will be quite limiting.</p> |
| <p>Options are:</p> |
| <ul class="simple"> |
| <li><p><strong>Font Compression</strong> Addition of some font compression algorithm in NuttX. |
| However, Chinese character bitmaps do not compress well: Many of them contain |
| so much data that there is not much of anything to compress. Some actually |
| expand under certain compression algorithms.</p></li> |
| <li><p><strong>Mass Storage</strong> A better option would be put the wide the fonts in file |
| system, in NAND or serial FLASH or on an SD card. In this case, additional |
| logic would be required to (1) format a font binary file and to (2) access |
| the font binary from the file system as needed.</p></li> |
| </ul> |
| </section> |
| </section> |
| </section> |
| |
| |
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