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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 <cairomm/cairomm.h></span>
<span class="preprocessor">#include <iostream></span>
<span class="preprocessor">#include <map></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're going to draw</span>
<span class="keyword">static</span> <span class="keyword">const</span> GlyphBounds glyphs[] =
{
{ <span class="charliteral">'c'</span>, 0.45, 0.5 },
{ <span class="charliteral">'a'</span>, 0.45, 0.5 },
{ <span class="charliteral">'i'</span>, 0.2, 0.75 },
{ <span class="charliteral">'r'</span>, 0.4, 0.5 },
{ <span class="charliteral">'o'</span>, 0.44, 0.5 },
{ <span class="charliteral">'m'</span>, 0.75, 0.5 },
{ <span class="charliteral">'!'</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&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<BoxFontFace></a> create()
{
<span class="keywordflow">return</span> <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<BoxFontFace></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&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<Cairo::ScaledFont></a>& <span class="comment">/*scaled_font*/</span>,
<span class="keyword">const</span> <a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<Cairo::Context></a>& <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> &extents)
{
<span class="keywordtype">double</span> <a name="a1"></a><a class="codeRef" 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 < <span class="keyword">sizeof</span> (glyphs) / <span class="keyword">sizeof</span> (GlyphBounds); ++i) {
<span class="keywordflow">if</span> (glyphs[i].width > max)
max = glyphs[i].width;
}
<span class="comment">// add some spacing between characters</span>
max += GLYPH_SPACING;
extents.max_x_advance = <a class="codeRef" 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&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<Cairo::ScaledFont></a>& <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>& 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 < <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&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<Cairo::ScaledFont></a>& <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&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<Cairo::Context></a>& 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>& metrics)
{
<span class="comment">// check that the glyph is in our table</span>
<span class="keywordflow">if</span> (glyph >= 1 && glyph <= <span class="keyword">sizeof</span>(glyphs)/<span class="keyword">sizeof</span>(GlyphBounds)) {
cr->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's positive Y axis is down and we want to draw up</span>
cr->rectangle(0.0, 0.0, glyphs[glyph-1].width, -glyphs[glyph-1].height);
cr->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&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<Cairo::ImageSurface></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&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<Cairo::Context></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->set_source_rgb(1.0, 1.0, 1.0);
cr->paint();
<span class="comment">// draw a little dot at the point where text will be drawn</span>
cr->arc(TEXT_ORIGIN_X, TEXT_ORIGIN_Y, FONT_SIZE / 4.0, 0, 2*M_PI);
cr->set_source_rgba(0.0, 1.0, 0.0, 0.5);
cr->fill();
<span class="comment">// draw the text</span>
cr->move_to(TEXT_ORIGIN_X, TEXT_ORIGIN_Y);
cr->set_source_rgb(0.8, 0.2, 0.2);
<a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<BoxFontFace></a> font = BoxFontFace::create();
cr->set_font_face(font);
cr->set_font_size(FONT_SIZE);
cr->show_text(<span class="stringliteral">"cairomm!"</span>);
<span class="comment">// Now show it with the toy text API to demonstrate how the glyphs match up</span>
cr->move_to(TEXT_ORIGIN_X, TEXT_ORIGIN_Y);
cr->set_source_rgba(0.2, 0.2, 0.2, 0.3);
<a class="code" href="classCairo_1_1RefPtr.html" title="RefPtr&lt;&gt; is a reference-counting shared smartpointer.">Cairo::RefPtr<Cairo::ToyFontFace></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">"Bitstream Charter"</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->set_font_face(toy_font);
cr->set_font_size(FONT_SIZE);
cr->show_text(<span class="stringliteral">"cairomm!"</span>);
<span class="keyword">const</span> <span class="keywordtype">char</span>* filename = <span class="stringliteral">"user-font.png"</span>;
<span class="keywordflow">try</span> {
surface->write_to_png(filename);
<a name="a8"></a><a class="codeRef" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01136.html#aaf93fdf0812752e0e02c501dea1b38f0">std::cout</a> << <span class="stringliteral">"Wrote Image "</span> << filename << <a name="a9"></a><a class="codeRef" 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" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a00469.html">std::exception</a>& e)
{
<a class="codeRef" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01136.html#aaf93fdf0812752e0e02c501dea1b38f0">std::cout</a> << <span class="stringliteral">"** Unable to write Image "</span> << filename << <a class="codeRef" 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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