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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<title>cairomm: user-font.cc</title>
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<div id="projectname">cairomm
 <span id="projectnumber">1.0</span>
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<div class="title">user-font.cc</div> </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"><div class="line"><span class="preprocessor">#include <cairomm/cairomm.h></span></div>
<div class="line"><span class="preprocessor">#include <iostream></span></div>
<div class="line"><span class="preprocessor">#include <map></span></div>
<div class="line"></div>
<div class="line"><span class="keyword">const</span> <span class="keywordtype">double</span> HEIGHT = 200.0;</div>
<div class="line"><span class="keyword">const</span> <span class="keywordtype">double</span> WIDTH = 400.0;</div>
<div class="line"><span class="keyword">const</span> <span class="keywordtype">double</span> FONT_SIZE = 64.0;</div>
<div class="line"><span class="keyword">const</span> <span class="keywordtype">double</span> TEXT_ORIGIN_Y = (HEIGHT / 2.0) + (FONT_SIZE / 2.0);</div>
<div class="line"><span class="keyword">const</span> <span class="keywordtype">double</span> TEXT_ORIGIN_X = 50.0; <span class="comment">// arbitrary</span></div>
<div class="line"><span class="keyword">const</span> <span class="keywordtype">double</span> GLYPH_SPACING = 0.1;</div>
<div class="line"></div>
<div class="line"><span class="keyword">struct </span>GlyphBounds</div>
<div class="line">{</div>
<div class="line"> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> glyph;</div>
<div class="line"> <span class="keywordtype">double</span> width;</div>
<div class="line"> <span class="keywordtype">double</span> height;</div>
<div class="line">};</div>
<div class="line"></div>
<div class="line"><span class="comment">// an array that stores the bounds of the glyphs that we're going to draw</span></div>
<div class="line"><span class="keyword">static</span> <span class="keyword">const</span> GlyphBounds glyphs[] =</div>
<div class="line">{</div>
<div class="line"> { <span class="charliteral">'c'</span>, 0.45, 0.5 },</div>
<div class="line"> { <span class="charliteral">'a'</span>, 0.45, 0.5 },</div>
<div class="line"> { <span class="charliteral">'i'</span>, 0.2, 0.75 },</div>
<div class="line"> { <span class="charliteral">'r'</span>, 0.4, 0.5 },</div>
<div class="line"> { <span class="charliteral">'o'</span>, 0.44, 0.5 },</div>
<div class="line"> { <span class="charliteral">'m'</span>, 0.75, 0.5 },</div>
<div class="line"> { <span class="charliteral">'!'</span>, 0.2, 0.75 }</div>
<div class="line">};</div>
<div class="line"></div>
<div class="line"><span class="comment">// A *very* simple font that just draws a box for every glyph</span></div>
<div class="line"><span class="keyword">class </span>BoxFontFace : <span class="keyword">public</span> <a name="_a0"></a><a class="code" href="classCairo_1_1UserFontFace.html">Cairo::UserFontFace</a></div>
<div class="line">{</div>
<div class="line"><span class="keyword">public</span>:</div>
<div class="line"> <span class="comment">// Derived user font classes should have a factory method to create an object</span></div>
<div class="line"> <span class="comment">// and return it with a RefPtr</span></div>
<div class="line"> <span class="keyword">static</span> <a name="_a1"></a><a class="code" href="classCairo_1_1RefPtr.html">Cairo::RefPtr<BoxFontFace></a> create()</div>
<div class="line"> {</div>
<div class="line"> <span class="keywordflow">return</span> <a class="code" href="classCairo_1_1RefPtr.html">Cairo::RefPtr<BoxFontFace></a>(<span class="keyword">new</span> BoxFontFace());</div>
<div class="line"> }</div>
<div class="line"></div>
<div class="line"> Cairo::ErrorStatus</div>
<div class="line"> <a name="a2"></a><a class="code" href="classCairo_1_1UserFontFace.html#af3f1d3a53a7be1d84a20609984473e07">init</a>(<span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html">Cairo::RefPtr<Cairo::ScaledFont></a>& <span class="comment">/*scaled_font*/</span>,</div>
<div class="line"> <span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html">Cairo::RefPtr<Cairo::Context></a>& <span class="comment">/*cr*/</span>,</div>
<div class="line"> <a class="code" href="namespaceCairo.html#aa7da46c699a67bfbdd5400af7e6b7b39">Cairo::FontExtents</a> &extents)<span class="keyword"> override</span></div>
<div class="line"><span class="keyword"> </span>{</div>
<div class="line"> <span class="keywordtype">double</span> <a name="a3"></a><a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01656.html#ga8010118c8f0472172a808754940c3b66">max</a> = 0;</div>
<div class="line"> <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i = 0; i < <span class="keyword">sizeof</span> (glyphs) / <span class="keyword">sizeof</span> (GlyphBounds); ++i) {</div>
<div class="line"> <span class="keywordflow">if</span> (glyphs[i].width > max)</div>
<div class="line"> max = glyphs[i].width;</div>
<div class="line"> }</div>
<div class="line"> <span class="comment">// add some spacing between characters</span></div>
<div class="line"> max += GLYPH_SPACING;</div>
<div class="line"> 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/a01656.html#ga8010118c8f0472172a808754940c3b66">max</a>;</div>
<div class="line"> <span class="keywordflow">return</span> CAIRO_STATUS_SUCCESS;</div>
<div class="line"> }</div>
<div class="line"></div>
<div class="line"> Cairo::ErrorStatus</div>
<div class="line"> <a name="a4"></a><a class="code" href="classCairo_1_1UserFontFace.html#a43cd65b62eab686477d3773e6fd98b46">unicode_to_glyph</a> (<span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html">Cairo::RefPtr<Cairo::ScaledFont></a>& <span class="comment">/*scaled_font*/</span>,</div>
<div class="line"> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> unicode, <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span>& glyph)<span class="keyword"> override</span></div>
<div class="line"><span class="keyword"> </span>{</div>
<div class="line"> glyph = 0;</div>
<div class="line"> <span class="comment">// yes this is a stupid an ineffienct way to do this but we only have a few</span></div>
<div class="line"> <span class="comment">// glyphs and this is just demonstration code</span></div>
<div class="line"> <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i = 0; i < <span class="keyword">sizeof</span> (glyphs) / <span class="keyword">sizeof</span> (GlyphBounds); ++i) {</div>
<div class="line"> <span class="keywordflow">if</span> (glyphs[i].glyph == unicode) {</div>
<div class="line"> <span class="comment">// glyph 0 is often a special glyph-not-found value, so offset it by 1</span></div>
<div class="line"> glyph = i+1;</div>
<div class="line"> <span class="keywordflow">break</span>;</div>
<div class="line"> }</div>
<div class="line"> }</div>
<div class="line"> <span class="keywordflow">return</span> CAIRO_STATUS_SUCCESS;</div>
<div class="line"> }</div>
<div class="line"></div>
<div class="line"> Cairo::ErrorStatus</div>
<div class="line"> <a name="a5"></a><a class="code" href="classCairo_1_1UserFontFace.html#a2e53435e92f9975213bd19969cb69375">render_glyph</a>(<span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html">Cairo::RefPtr<Cairo::ScaledFont></a>& <span class="comment">/*scaled_font*/</span>,</div>
<div class="line"> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> glyph,</div>
<div class="line"> <span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html">Cairo::RefPtr<Cairo::Context></a>& cr,</div>
<div class="line"> <a class="code" href="namespaceCairo.html#af6d8a4744616383984c99f8f052c7a5d">Cairo::TextExtents</a>& metrics)<span class="keyword"> override</span></div>
<div class="line"><span class="keyword"> </span>{</div>
<div class="line"> <span class="comment">// check that the glyph is in our table</span></div>
<div class="line"> <span class="keywordflow">if</span> (glyph >= 1 && glyph <= <span class="keyword">sizeof</span>(glyphs)/<span class="keyword">sizeof</span>(GlyphBounds)) {</div>
<div class="line"> cr-><a name="a6"></a><a class="code" href="classCairo_1_1Context.html#a9ad2649d95e81a65aa0c581c4345375e">set_line_width</a>(0.05);</div>
<div class="line"> <span class="comment">// Need a negative Y value since the text origin is at the bottom left point</span></div>
<div class="line"> <span class="comment">// and cairo's positive Y axis is down and we want to draw up</span></div>
<div class="line"> cr-><a name="a7"></a><a class="code" href="classCairo_1_1Context.html#a85ee124b89c43dc29ff0d964bd005c11">rectangle</a>(0.0, 0.0, glyphs[glyph-1].width, -glyphs[glyph-1].height);</div>
<div class="line"> cr-><a name="a8"></a><a class="code" href="classCairo_1_1Context.html#a8e4acbb44f4b3fac00ee93f6251d6d17">stroke</a>();</div>
<div class="line"> metrics.x_advance = glyphs[glyph-1].width + GLYPH_SPACING;</div>
<div class="line"> }</div>
<div class="line"> <span class="keywordflow">return</span> CAIRO_STATUS_SUCCESS;</div>
<div class="line"> }</div>
<div class="line"></div>
<div class="line"><span class="keyword">protected</span>:</div>
<div class="line"> <span class="comment">// FontFace is a ref-counted object, so the constructor should be protected so</span></div>
<div class="line"> <span class="comment">// it is not created without a refptr to manage it. See the create() method</span></div>
<div class="line"> BoxFontFace() : UserFontFace() { }</div>
<div class="line">};</div>
<div class="line"></div>
<div class="line"><span class="keywordtype">int</span> main(<span class="keywordtype">int</span>, <span class="keywordtype">char</span>**)</div>
<div class="line">{</div>
<div class="line"> <span class="keyword">auto</span> surface =</div>
<div class="line"> <a name="a9"></a><a class="code" href="classCairo_1_1ImageSurface.html#a82887e1a0480ab16aa891e135f2b28d6">Cairo::ImageSurface::create</a>(<a name="a10"></a><a class="code" href="namespaceCairo.html#ad3f86970e1bd354b263303c9b8759166afc97f1888578477fd656cf72d3421fbc">Cairo::FORMAT_ARGB32</a>, WIDTH, HEIGHT);</div>
<div class="line"> <span class="keyword">auto</span> cr = <a name="a11"></a><a class="code" href="classCairo_1_1Context.html#a9a27f6ec57d788fd3ecbc310aeb24d99">Cairo::Context::create</a>(surface);</div>
<div class="line"> <span class="comment">// fill background in white</span></div>
<div class="line"> cr-><a name="a12"></a><a class="code" href="classCairo_1_1Context.html#aff3f3fc62bdf862646bb8cc568c30b2a">set_source_rgb</a>(1.0, 1.0, 1.0);</div>
<div class="line"> cr-><a name="a13"></a><a class="code" href="classCairo_1_1Context.html#ad919eae3bc3b9827a3c1ceff2d86833e">paint</a>();</div>
<div class="line"></div>
<div class="line"> <span class="comment">// draw a little dot at the point where text will be drawn</span></div>
<div class="line"> cr-><a name="a14"></a><a class="code" href="classCairo_1_1Context.html#aaa96080beea581244f0a3838fb7c9ee6">arc</a>(TEXT_ORIGIN_X, TEXT_ORIGIN_Y, FONT_SIZE / 4.0, 0, 2*M_PI);</div>
<div class="line"> cr-><a name="a15"></a><a class="code" href="classCairo_1_1Context.html#af9267aed8eb866701178dcada6c7e51a">set_source_rgba</a>(0.0, 1.0, 0.0, 0.5);</div>
<div class="line"> cr-><a name="a16"></a><a class="code" href="classCairo_1_1Context.html#a0a484790884dd138108b07c0ebbbe21d">fill</a>();</div>
<div class="line"></div>
<div class="line"> <span class="comment">// draw the text</span></div>
<div class="line"> cr-><a name="a17"></a><a class="code" href="classCairo_1_1Context.html#a4086700b5f780fd3fb94bea941895022">move_to</a>(TEXT_ORIGIN_X, TEXT_ORIGIN_Y);</div>
<div class="line"> cr-><a class="code" href="classCairo_1_1Context.html#aff3f3fc62bdf862646bb8cc568c30b2a">set_source_rgb</a>(0.8, 0.2, 0.2);</div>
<div class="line"> <span class="keyword">auto</span> font = BoxFontFace::create();</div>
<div class="line"> cr-><a name="a18"></a><a class="code" href="classCairo_1_1Context.html#a9b344db51097aba30e36452e1364faef">set_font_face</a>(font);</div>
<div class="line"> cr-><a name="a19"></a><a class="code" href="classCairo_1_1Context.html#ac8a04a09c2e871a470fd030edb45b024">set_font_size</a>(FONT_SIZE);</div>
<div class="line"> cr-><a name="a20"></a><a class="code" href="classCairo_1_1Context.html#a584596d6f12dbea30519b908cacce038">show_text</a>(<span class="stringliteral">"cairomm!"</span>);</div>
<div class="line"></div>
<div class="line"> <span class="comment">// Now show it with the toy text API to demonstrate how the glyphs match up</span></div>
<div class="line"> cr-><a class="code" href="classCairo_1_1Context.html#a4086700b5f780fd3fb94bea941895022">move_to</a>(TEXT_ORIGIN_X, TEXT_ORIGIN_Y);</div>
<div class="line"> cr-><a class="code" href="classCairo_1_1Context.html#af9267aed8eb866701178dcada6c7e51a">set_source_rgba</a>(0.2, 0.2, 0.2, 0.3);</div>
<div class="line"> <span class="keyword">auto</span> toy_font =</div>
<div class="line"> <a name="a21"></a><a class="code" href="classCairo_1_1ToyFontFace.html#a07c0ca7fd0dc54c31bfa1d8a813aff59">Cairo::ToyFontFace::create</a>(<span class="stringliteral">"Bitstream Charter"</span>,</div>
<div class="line"> <a name="a22"></a><a class="code" href="namespaceCairo.html#a0a2c19fefac301a702a6b7fdb368bf55a428cfea8fca5951033f3d433855cb97d">Cairo::FONT_SLANT_NORMAL</a>,</div>
<div class="line"> <a name="a23"></a><a class="code" href="namespaceCairo.html#ad8514818fb9292a5864b57f4b8a1e546a438bd2ac850ef23ce7a537ae3395f398">Cairo::FONT_WEIGHT_BOLD</a>);</div>
<div class="line"> cr-><a class="code" href="classCairo_1_1Context.html#a9b344db51097aba30e36452e1364faef">set_font_face</a>(toy_font);</div>
<div class="line"> cr-><a class="code" href="classCairo_1_1Context.html#ac8a04a09c2e871a470fd030edb45b024">set_font_size</a>(FONT_SIZE);</div>
<div class="line"> cr-><a class="code" href="classCairo_1_1Context.html#a584596d6f12dbea30519b908cacce038">show_text</a>(<span class="stringliteral">"cairomm!"</span>);</div>
<div class="line"></div>
<div class="line"> <span class="keyword">const</span> <span class="keywordtype">char</span>* filename = <span class="stringliteral">"user-font.png"</span>;</div>
<div class="line"> <span class="keywordflow">try</span> {</div>
<div class="line"> surface->write_to_png(filename);</div>
<div class="line"> <a name="a24"></a>std::cout << <span class="stringliteral">"Wrote Image "</span> << filename << <a name="a25"></a><a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01616.html#a8b3758bb8f17c440c7963363f42f69f3">std::endl</a>;</div>
<div class="line"> <span class="keywordflow">return</span> 0;</div>
<div class="line"> } <span class="keywordflow">catch</span> (<span class="keyword">const</span> <a name="_a26"></a><a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a00694.html">std::exception</a>& e)</div>
<div class="line"> {</div>
<div class="line"> std::cout << <span class="stringliteral">"** Unable to write Image "</span> << filename << <a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01616.html#a8b3758bb8f17c440c7963363f42f69f3">std::endl</a>;</div>
<div class="line"> <span class="keywordflow">return</span> 1;</div>
<div class="line"> }</div>
<div class="line">}</div>
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