1 files changed, 127 insertions, 0 deletions
diff --git a/src/2geom/cairo-path-sink.cpp b/src/2geom/cairo-path-sink.cpp
new file mode 100644
index 0000000..a04f715
--- /dev/null
+++ b/src/2geom/cairo-path-sink.cpp
@@ -0,0 +1,127 @@
+/**
+ * @file
+ * @brief  Path sink for Cairo contexts
+ *//*
+ * Copyright 2014 Krzysztof Kosiński
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, output to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ *
+ */
+
+#ifdef HAVE_CAIRO
+
+#include <cairo.h>
+#include <2geom/cairo-path-sink.h>
+#include <2geom/elliptical-arc.h>
+
+namespace Geom {
+
+CairoPathSink::CairoPathSink(cairo_t *cr)
+    : _cr(cr)
+{}
+
+void CairoPathSink::moveTo(Point const &p)
+{
+    cairo_move_to(_cr, p[X], p[Y]);
+    _current_point = p;
+}
+
+void CairoPathSink::lineTo(Point const &p)
+{
+    cairo_line_to(_cr, p[X], p[Y]);
+    _current_point = p;
+}
+
+void CairoPathSink::curveTo(Point const &p1, Point const &p2, Point const &p3)
+{
+    cairo_curve_to(_cr, p1[X], p1[Y], p2[X], p2[Y], p3[X], p3[Y]);
+    _current_point = p3;
+}
+
+void CairoPathSink::quadTo(Point const &p1, Point const &p2)
+{
+    // degree-elevate to cubic Bezier, since Cairo doesn't do quad Beziers
+    // google "Bezier degree elevation" for more info
+    Point q1 = (1./3.) * _current_point + (2./3.) * p1;
+    Point q2 = (2./3.) * p1 + (1./3.) * p2;
+    // q3 = p2
+    cairo_curve_to(_cr, q1[X], q1[Y], q2[X], q2[Y], p2[X], p2[Y]);
+    _current_point = p2;
+}
+
+void CairoPathSink::arcTo(double rx, double ry, double angle,
+                          bool large_arc, bool sweep, Point const &p)
+{
+    EllipticalArc arc(_current_point, rx, ry, angle, large_arc, sweep, p);
+    // Cairo only does circular arcs.
+    // To do elliptical arcs, we must use a temporary transform.
+    Affine uct = arc.unitCircleTransform();
+
+    // TODO move Cairo-2Geom matrix conversion into a common location
+    cairo_matrix_t cm;
+    cm.xx = uct[0];
+    cm.xy = uct[2];
+    cm.x0 = uct[4];
+    cm.yx = uct[1];
+    cm.yy = uct[3];
+    cm.y0 = uct[5];
+
+    cairo_save(_cr);
+    cairo_transform(_cr, &cm);
+    if (sweep) {
+        cairo_arc(_cr, 0, 0, 1, arc.initialAngle(), arc.finalAngle());
+    } else {
+        cairo_arc_negative(_cr, 0, 0, 1, arc.initialAngle(), arc.finalAngle());
+    }
+    _current_point = p;
+    cairo_restore(_cr);
+
+    /* Note that an extra linear segment will be inserted before the arc
+     * if Cairo considers the current point distinct from the initial point
+     * of the arc; we could partially alleviate this by not emitting
+     * linear segments that are followed by arc segments, but this would require
+     * buffering the input curves. */
+}
+           
+void CairoPathSink::closePath()
+{
+    cairo_close_path(_cr);
+}
+
+void CairoPathSink::flush() {}
+
+} // namespace Geom
+
+#endif
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :