diff options
| author | Yuval Adam <yuv.adm@gmail.com> | 2014-08-08 14:42:07 +0300 |
|---|---|---|
| committer | Yuval Adam <yuv.adm@gmail.com> | 2014-08-08 14:42:07 +0300 |
| commit | a6163888f3c56123b1db313743c6147ba498732c (patch) | |
| tree | ff7d15d991d1d09ba6cbc0cec80924f57445bfdd /third_party/windows/fltk-1.1.10/src/fl_curve.cxx | |
| parent | c3e4c9a25c2910d2d66d52215b3406b13d5b23d5 (diff) | |
Add third_party libs
Diffstat (limited to 'third_party/windows/fltk-1.1.10/src/fl_curve.cxx')
| -rw-r--r-- | third_party/windows/fltk-1.1.10/src/fl_curve.cxx | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/third_party/windows/fltk-1.1.10/src/fl_curve.cxx b/third_party/windows/fltk-1.1.10/src/fl_curve.cxx new file mode 100644 index 0000000..5007e9a --- /dev/null +++ b/third_party/windows/fltk-1.1.10/src/fl_curve.cxx @@ -0,0 +1,106 @@ +//
+// "$Id: fl_curve.cxx 5190 2006-06-09 16:16:34Z mike $"
+//
+// Bezier curve functions for the Fast Light Tool Kit (FLTK).
+//
+// Copyright 1998-2005 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
+//
+
+// 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 algorithim, please send it!
+
+#include <FL/fl_draw.H>
+#include <math.h>
+
+void fl_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 5190 2006-06-09 16:16:34Z mike $".
+//
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