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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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        <title>cairomm: user-font.cc</title>
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<h1>user-font.cc</h1> </div>
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<p>A relatively simple example of using <a class="el" href="classCairo_1_1UserFontFace.html" title="Font support with font data provided by the user.">Cairo::UserFontFace</a></p>
<div class="fragment"><pre class="fragment"><span class="preprocessor">#include &lt;cairomm/cairomm.h&gt;</span>
<span class="preprocessor">#include &lt;iostream&gt;</span>
<span class="preprocessor">#include &lt;map&gt;</span>

<span class="keyword">const</span> <span class="keywordtype">double</span> HEIGHT = 200.0;
<span class="keyword">const</span> <span class="keywordtype">double</span> WIDTH = 400.0;
<span class="keyword">const</span> <span class="keywordtype">double</span> FONT_SIZE = 64.0;
<span class="keyword">const</span> <span class="keywordtype">double</span> TEXT_ORIGIN_Y = (HEIGHT / 2.0) + (FONT_SIZE / 2.0);
<span class="keyword">const</span> <span class="keywordtype">double</span> TEXT_ORIGIN_X = 50.0; <span class="comment">// arbitrary</span>
<span class="keyword">const</span> <span class="keywordtype">double</span> GLYPH_SPACING = 0.1;

<span class="keyword">struct </span>GlyphBounds
{
  <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> glyph;
  <span class="keywordtype">double</span> width;
  <span class="keywordtype">double</span> height;
};

<span class="comment">// an array that stores the bounds of the glyphs that we&#39;re going to draw</span>
<span class="keyword">static</span> <span class="keyword">const</span> GlyphBounds glyphs[] =
{
  { <span class="charliteral">&#39;c&#39;</span>, 0.45, 0.5 },
  { <span class="charliteral">&#39;a&#39;</span>, 0.45, 0.5 },
  { <span class="charliteral">&#39;i&#39;</span>, 0.2, 0.75 },
  { <span class="charliteral">&#39;r&#39;</span>, 0.4, 0.5 },
  { <span class="charliteral">&#39;o&#39;</span>, 0.44, 0.5 },
  { <span class="charliteral">&#39;m&#39;</span>, 0.75, 0.5 },
  { <span class="charliteral">&#39;!&#39;</span>, 0.2, 0.75 }
};

<span class="comment">// A *very* simple font that just draws a box for every glyph</span>
<span class="keyword">class </span>BoxFontFace : <span class="keyword">public</span> Cairo::UserFontFace
{
<span class="keyword">public</span>:
  <span class="comment">// Derived user font classes should have a factory method to create an object</span>
  <span class="comment">// and return it with a RefPtr</span>
  <span class="keyword">static</span> <a name="_a0"></a><a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;BoxFontFace&gt;</a> create()
  {
    <span class="keywordflow">return</span> <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;BoxFontFace&gt;</a>(<span class="keyword">new</span> BoxFontFace());
  }

  <span class="keyword">virtual</span> Cairo::ErrorStatus
    init(<span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;Cairo::ScaledFont&gt;</a>&amp; <span class="comment">/*scaled_font*/</span>,
         <span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;Cairo::Context&gt;</a>&amp; <span class="comment">/*cr*/</span>,
         <a class="code" href="namespaceCairo.html#aa7da46c699a67bfbdd5400af7e6b7b39" title="See the cairo_font_extents_t reference in the cairo manual for more information.">Cairo::FontExtents</a> &amp;extents)
  {
    <span class="keywordtype">double</span> <a name="a1"></a><a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01176.html#ga8010118c8f0472172a808754940c3b66">max</a> = 0;
    <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i = 0; i &lt; <span class="keyword">sizeof</span> (glyphs) / <span class="keyword">sizeof</span> (GlyphBounds); ++i) {
      <span class="keywordflow">if</span> (glyphs[i].width &gt; max)
        max = glyphs[i].width;
    }
    <span class="comment">// add some spacing between characters</span>
    max += GLYPH_SPACING;
    extents.max_x_advance = <a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01176.html#ga8010118c8f0472172a808754940c3b66">max</a>;
    <span class="keywordflow">return</span> CAIRO_STATUS_SUCCESS;
  }

  <span class="keyword">virtual</span> Cairo::ErrorStatus
  unicode_to_glyph (<span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;Cairo::ScaledFont&gt;</a>&amp; <span class="comment">/*scaled_font*/</span>,
                    <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> unicode, <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span>&amp; glyph)
  {
    glyph = 0;
    <span class="comment">// yes this is a stupid an ineffienct way to do this but we only have a few</span>
    <span class="comment">// glyphs and this is just demonstration code</span>
    <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i = 0; i &lt; <span class="keyword">sizeof</span> (glyphs) / <span class="keyword">sizeof</span> (GlyphBounds); ++i) {
      <span class="keywordflow">if</span> (glyphs[i].glyph == unicode) {
        <span class="comment">// glyph 0 is often a special glyph-not-found value, so offset it by 1</span>
        glyph = i+1;
        <span class="keywordflow">break</span>;
      }
    }
    <span class="keywordflow">return</span> CAIRO_STATUS_SUCCESS;
  }

  <span class="keyword">virtual</span> Cairo::ErrorStatus
  render_glyph(<span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;Cairo::ScaledFont&gt;</a>&amp; <span class="comment">/*scaled_font*/</span>,
               <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> glyph,
               <span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;Cairo::Context&gt;</a>&amp; cr,
               <a class="code" href="namespaceCairo.html#af6d8a4744616383984c99f8f052c7a5d" title="See the cairo_text_extents_t reference in the cairo manual for more information.">Cairo::TextExtents</a>&amp; metrics)
  {
    <span class="comment">// check that the glyph is in our table</span>
    <span class="keywordflow">if</span> (glyph &gt;= 1 &amp;&amp; glyph &lt;= <span class="keyword">sizeof</span>(glyphs)/<span class="keyword">sizeof</span>(GlyphBounds)) {
      cr-&gt;set_line_width(0.05);
      <span class="comment">// Need a negative Y value since the text origin is at the bottom left point</span>
      <span class="comment">// and cairo&#39;s positive Y axis is down and we want to draw up</span>
      cr-&gt;rectangle(0.0, 0.0, glyphs[glyph-1].width, -glyphs[glyph-1].height);
      cr-&gt;stroke();
      metrics.x_advance = glyphs[glyph-1].width + GLYPH_SPACING;
    }
    <span class="keywordflow">return</span> CAIRO_STATUS_SUCCESS;
  }

<span class="keyword">protected</span>:
  <span class="comment">// FontFace is a ref-counted object, so the constructor should be protected so</span>
  <span class="comment">// it is not created without a refptr to manage it. See the create() method</span>
  BoxFontFace() : UserFontFace() { }
};

<span class="keywordtype">int</span> main(<span class="keywordtype">int</span>, <span class="keywordtype">char</span>**)
{
  <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;Cairo::ImageSurface&gt;</a> surface =
    <a name="a2"></a><a class="code" href="classCairo_1_1ImageSurface.html#a82887e1a0480ab16aa891e135f2b28d6" title="Creates an image surface of the specified format and dimensions.">Cairo::ImageSurface::create</a>(<a name="a3"></a><a class="code" href="namespaceCairo.html#ad3f86970e1bd354b263303c9b8759166afc97f1888578477fd656cf72d3421fbc">Cairo::FORMAT_ARGB32</a>, WIDTH, HEIGHT);
  <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;Cairo::Context&gt;</a> cr = <a name="a4"></a><a class="code" href="classCairo_1_1Context.html#a9a27f6ec57d788fd3ecbc310aeb24d99">Cairo::Context::create</a>(surface);
  <span class="comment">// fill background in white</span>
  cr-&gt;set_source_rgb(1.0, 1.0, 1.0);
  cr-&gt;paint();

  <span class="comment">// draw a little dot at the point where text will be drawn</span>
  cr-&gt;arc(TEXT_ORIGIN_X, TEXT_ORIGIN_Y, FONT_SIZE / 4.0, 0, 2*M_PI);
  cr-&gt;set_source_rgba(0.0, 1.0, 0.0, 0.5);
  cr-&gt;fill();

  <span class="comment">// draw the text</span>
  cr-&gt;move_to(TEXT_ORIGIN_X, TEXT_ORIGIN_Y);
  cr-&gt;set_source_rgb(0.8, 0.2, 0.2);
  <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;BoxFontFace&gt;</a> font = BoxFontFace::create();
  cr-&gt;set_font_face(font);
  cr-&gt;set_font_size(FONT_SIZE);
  cr-&gt;show_text(<span class="stringliteral">&quot;cairomm!&quot;</span>);

  <span class="comment">// Now show it with the toy text API to demonstrate how the glyphs match up</span>
  cr-&gt;move_to(TEXT_ORIGIN_X, TEXT_ORIGIN_Y);
  cr-&gt;set_source_rgba(0.2, 0.2, 0.2, 0.3);
  <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&amp;lt;&amp;gt; is a reference-counting shared smartpointer.">Cairo::RefPtr&lt;Cairo::ToyFontFace&gt;</a> toy_font =
    <a name="a5"></a><a class="code" href="classCairo_1_1ToyFontFace.html#a07c0ca7fd0dc54c31bfa1d8a813aff59" title="Creates a font face from a triplet of family, slant, and weight.">Cairo::ToyFontFace::create</a>(<span class="stringliteral">&quot;Bitstream Charter&quot;</span>,
                               <a name="a6"></a><a class="code" href="namespaceCairo.html#a0a2c19fefac301a702a6b7fdb368bf55a428cfea8fca5951033f3d433855cb97d">Cairo::FONT_SLANT_NORMAL</a>,
                               <a name="a7"></a><a class="code" href="namespaceCairo.html#ad8514818fb9292a5864b57f4b8a1e546a438bd2ac850ef23ce7a537ae3395f398">Cairo::FONT_WEIGHT_BOLD</a>);
  cr-&gt;set_font_face(toy_font);
  cr-&gt;set_font_size(FONT_SIZE);
  cr-&gt;show_text(<span class="stringliteral">&quot;cairomm!&quot;</span>);

  <span class="keyword">const</span> <span class="keywordtype">char</span>* filename = <span class="stringliteral">&quot;user-font.png&quot;</span>;
  <span class="keywordflow">try</span> {
    surface-&gt;write_to_png(filename);
    <a name="a8"></a><a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01136.html#aaf93fdf0812752e0e02c501dea1b38f0">std::cout</a> &lt;&lt; <span class="stringliteral">&quot;Wrote Image &quot;</span> &lt;&lt; filename &lt;&lt; <a name="a9"></a><a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01136.html#a9e2ba1ed9813a1f03adc9a87dbf491a5">std::endl</a>;
    <span class="keywordflow">return</span> 0;
  } <span class="keywordflow">catch</span> (<span class="keyword">const</span> <a name="_a10"></a><a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a00469.html">std::exception</a>&amp; e)
  {
    <a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01136.html#aaf93fdf0812752e0e02c501dea1b38f0">std::cout</a> &lt;&lt; <span class="stringliteral">&quot;** Unable to write Image &quot;</span> &lt;&lt; filename &lt;&lt; <a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01136.html#a9e2ba1ed9813a1f03adc9a87dbf491a5">std::endl</a>;
    <span class="keywordflow">return</span> 1;
  }
}
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