Include a stripped-down version of FLTK in tree and add a USE_INCLUDED_FLTK option to build against it.
git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4603 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/common/fltk/src/fl_curve.cxx b/common/fltk/src/fl_curve.cxx
new file mode 100644
index 0000000..2f86552
--- /dev/null
+++ b/common/fltk/src/fl_curve.cxx
@@ -0,0 +1,110 @@
+//
+// "$Id: fl_curve.cxx 7903 2010-11-28 21:06:39Z matt $"
+//
+// Bezier curve functions for the Fast Light Tool Kit (FLTK).
+//
+// Copyright 1998-2010 by Bill Spitzak and others.
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Library General Public
+// License as published by the Free Software Foundation; either
+// version 2 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// Library General Public License for more details.
+//
+// You should have received a copy of the GNU Library General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+// USA.
+//
+// Please report all bugs and problems on the following page:
+//
+// http://www.fltk.org/str.php
+//
+
+/**
+ \file fl_curve.cxx
+ \brief Utility for drawing Bezier curves, adding the points to the
+ current fl_begin/fl_vertex/fl_end path.
+
+ Incremental math implementation:
+ I very much doubt this is optimal! From Foley/vanDam page 511.
+ If anybody has a better algorithm, please send it!
+*/
+
+#include <FL/fl_draw.H>
+#include <math.h>
+
+void Fl_Graphics_Driver::curve(double X0, double Y0,
+ double X1, double Y1,
+ double X2, double Y2,
+ double X3, double Y3) {
+
+ double x = fl_transform_x(X0,Y0);
+ double y = fl_transform_y(X0,Y0);
+
+ // draw point 0:
+ fl_transformed_vertex(x,y);
+
+ double x1 = fl_transform_x(X1,Y1);
+ double yy1 = fl_transform_y(X1,Y1);
+ double x2 = fl_transform_x(X2,Y2);
+ double y2 = fl_transform_y(X2,Y2);
+ double x3 = fl_transform_x(X3,Y3);
+ double y3 = fl_transform_y(X3,Y3);
+
+ // find the area:
+ double a = fabs((x-x2)*(y3-yy1)-(y-y2)*(x3-x1));
+ double b = fabs((x-x3)*(y2-yy1)-(y-y3)*(x2-x1));
+ if (b > a) a = b;
+
+ // use that to guess at the number of segments:
+ int n = int(sqrt(a)/4);
+ if (n > 1) {
+ if (n > 100) n = 100; // make huge curves not hang forever
+
+ double e = 1.0/n;
+
+ // calculate the coefficients of 3rd order equation:
+ double xa = (x3-3*x2+3*x1-x);
+ double xb = 3*(x2-2*x1+x);
+ double xc = 3*(x1-x);
+ // calculate the forward differences:
+ double dx1 = ((xa*e+xb)*e+xc)*e;
+ double dx3 = 6*xa*e*e*e;
+ double dx2 = dx3 + 2*xb*e*e;
+
+ // calculate the coefficients of 3rd order equation:
+ double ya = (y3-3*y2+3*yy1-y);
+ double yb = 3*(y2-2*yy1+y);
+ double yc = 3*(yy1-y);
+ // calculate the forward differences:
+ double dy1 = ((ya*e+yb)*e+yc)*e;
+ double dy3 = 6*ya*e*e*e;
+ double dy2 = dy3 + 2*yb*e*e;
+
+ // draw points 1 .. n-2:
+ for (int m=2; m<n; m++) {
+ x += dx1;
+ dx1 += dx2;
+ dx2 += dx3;
+ y += dy1;
+ dy1 += dy2;
+ dy2 += dy3;
+ fl_transformed_vertex(x,y);
+ }
+
+ // draw point n-1:
+ fl_transformed_vertex(x+dx1, y+dy1);
+ }
+
+ // draw point n:
+ fl_transformed_vertex(x3,y3);
+}
+
+//
+// End of "$Id: fl_curve.cxx 7903 2010-11-28 21:06:39Z matt $".
+//