f87393aaa1
Updated email addresses to point to fltk.org domain... Updated README and CHANGES files accordingly. Updated makeinclude and Makefile files to put -L../lib before the LDFLAGS/GLDFLAGS to avoid problem reported by Alexander. documentation/Makefile wasn't including makeinclude. Updated FLUID about window to show version 1.0.9. git-svn-id: file:///fltk/svn/fltk/branches/branch-1.0@1168 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
100 lines
3.1 KiB
C++
100 lines
3.1 KiB
C++
//
|
|
// "$Id: fl_curve.cxx,v 1.4.2.2 2000/06/05 21:21:06 mike Exp $"
|
|
//
|
|
// Bezier curve functions for the Fast Light Tool Kit (FLTK).
|
|
//
|
|
// Copyright 1998-2000 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 to "fltk-bugs@fltk.org".
|
|
//
|
|
|
|
// 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);
|
|
double x1 = fl_transform_x(X1,Y1);
|
|
double y1 = 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);
|
|
|
|
int n; { // find smaller size of bounding box
|
|
double lx = x; if (x1<lx) lx=x1; if (x2<lx) lx=x2; if (x3<lx) lx=x3;
|
|
double rx = x; if (x1>rx) rx=x1; if (x2>rx) rx=x2; if (x3>rx) rx=x3;
|
|
double ly = y; if (y1<ly) ly=y1; if (y2<ly) ly=y2; if (y3<ly) ly=y3;
|
|
double ry = y; if (y1>ry) ry=y1; if (y2>ry) ry=y2; if (y3>ry) ry=y3;
|
|
// calculate number of pieces to cut curve into:
|
|
n = int((rx-lx+ry-ly)/8); if (n < 3) n = 3;
|
|
}
|
|
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*y1-y);
|
|
double yb = 3*(y2-2*y1+y);
|
|
double yc = 3*(y1-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 point 0:
|
|
fl_transformed_vertex(x,y);
|
|
|
|
// 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,v 1.4.2.2 2000/06/05 21:21:06 mike Exp $".
|
|
//
|