Squashed 'third_party/cimg/' content from commit 4b66369
Change-Id: I7454d9107a08dba899fd4659731733049165ae0a
git-subtree-dir: third_party/cimg
git-subtree-split: 4b66369ab4e34a46119d6c43e9adce061bb40f4b
diff --git a/examples/mcf_levelsets2d.cpp b/examples/mcf_levelsets2d.cpp
new file mode 100644
index 0000000..1e3cbb3
--- /dev/null
+++ b/examples/mcf_levelsets2d.cpp
@@ -0,0 +1,120 @@
+/*
+ #
+ # File : mcf_levelsets2d.cpp
+ # ( C++ source file )
+ #
+ # Description : Implementation of the Mean Curvature Flow on a 2D curve,
+ # using the framework of Level Sets.
+ # This file is a part of the CImg Library project.
+ # ( http://cimg.eu )
+ #
+ # Copyright : David Tschumperle
+ # ( http://tschumperle.users.greyc.fr/ )
+ #
+ # License : CeCILL v2.0
+ # ( http://www.cecill.info/licences/Licence_CeCILL_V2-en.html )
+ #
+ # This software is governed by the CeCILL license under French law and
+ # abiding by the rules of distribution of free software. You can use,
+ # modify and/ or redistribute the software under the terms of the CeCILL
+ # license as circulated by CEA, CNRS and INRIA at the following URL
+ # "http://www.cecill.info".
+ #
+ # As a counterpart to the access to the source code and rights to copy,
+ # modify and redistribute granted by the license, users are provided only
+ # with a limited warranty and the software's author, the holder of the
+ # economic rights, and the successive licensors have only limited
+ # liability.
+ #
+ # In this respect, the user's attention is drawn to the risks associated
+ # with loading, using, modifying and/or developing or reproducing the
+ # software by the user in light of its specific status of free software,
+ # that may mean that it is complicated to manipulate, and that also
+ # therefore means that it is reserved for developers and experienced
+ # professionals having in-depth computer knowledge. Users are therefore
+ # encouraged to load and test the software's suitability as regards their
+ # requirements in conditions enabling the security of their systems and/or
+ # data to be ensured and, more generally, to use and operate it in the
+ # same conditions as regards security.
+ #
+ # The fact that you are presently reading this means that you have had
+ # knowledge of the CeCILL license and that you accept its terms.
+ #
+*/
+
+#include "CImg.h"
+using namespace cimg_library;
+#undef min
+#undef max
+
+// Retrieve the curve corresponding to the zero level set of the distance function.
+template<typename T>
+CImg<unsigned char> get_level0(const CImg<T>& img) {
+ CImg<unsigned char> dest(img);
+ CImg_2x2(I,T); Inn = 0;
+ cimg_for2x2(img,x,y,0,0,I,T) if (Icc*Inc<0 || Icc*Icn<0) dest(x,y) = 255; else dest(x,y) = Icc<0?100:0;
+ return dest;
+}
+
+/*--------------------
+
+ Main procedure
+
+----------------------*/
+int main(int argc,char **argv) {
+ cimg_usage("Perform a Mean Curvature Flow on closed curves, using Level Sets");
+ const float dt = cimg_option("-dt",0.8f,"PDE time step");
+ const unsigned int nb_iterations = cimg_option("-iter",10000,"Number of iterations");
+
+ // Create a user-defined closed curve.
+ CImg<unsigned char> curve(256,256,1,2,0);
+ unsigned char col1[] = {0,255}, col2[] = {200,255}, col3[] = {255,255};
+ curve.draw_grid(20,20,0,0,false,false,col1,0.4f,0xCCCCCCCC,0xCCCCCCCC).
+ draw_text(5,5,"Please draw your curve\nin this window\n(Use your mouse)",col1);
+ CImgDisplay disp(curve,"Mean curvature flow",0);
+ int xo = -1, yo = -1, x0 = -1, y0 = -1, x1 = -1, y1 = -1;
+ while (!disp.is_closed() && (x0<0 || disp.button())) {
+ if (disp.button() && disp.mouse_x()>=0 && disp.mouse_y()>=0) {
+ if (x0<0) { xo = x0 = disp.mouse_x(); yo = y0 = disp.mouse_y(); } else {
+ x1 = disp.mouse_x(); y1 = disp.mouse_y();
+ curve.draw_line(x0,y0,x1,y1,col2).display(disp);
+ x0 = x1; y0 = y1;
+ }
+ }
+ disp.wait();
+ if (disp.is_resized()) disp.resize(disp);
+ }
+ curve.draw_line(x1,y1,xo,yo,col2).channel(0).draw_fill(0,0,col3);
+ CImg<> img = CImg<>(curve.get_shared_channel(0)).normalize(-1,1);
+
+ // Perform the "Mean Curvature Flow".
+ img.distance_eikonal(10);
+ CImg_3x3(I,float);
+ for (unsigned int iteration = 0; iteration<nb_iterations && !disp.is_closed() &&
+ !disp.is_keyQ() && !disp.is_keyESC(); ++iteration) {
+ CImg<float> velocity(img.width(),img.height(),img.depth(),img.spectrum());
+ float *ptrd = velocity.data(), veloc_max = 0;
+ cimg_for3x3(img,x,y,0,0,I,float) {
+ const float
+ ix = (Inc - Ipc)/2,
+ iy = (Icn - Icp)/2,
+ ixx = Inc + Ipc - 2*Icc,
+ iyy = Icn + Icp - 2*Icc,
+ ixy = (Ipp + Inn - Inp - Ipn)/4,
+ ngrad = ix*ix + iy*iy,
+ iee = (ngrad>1e-5)?((iy*iy*ixx - 2*ix*iy*ixy + ix*ix*iyy)/ngrad):0;
+ *(ptrd++) = iee;
+ if (iee>veloc_max) veloc_max = iee; else if (-iee>veloc_max) veloc_max = -iee;
+ }
+ if (veloc_max>0) img+=(velocity*=dt/veloc_max);
+ if (!(iteration%10)) {
+ get_level0(img).resize(disp.width(),disp.height()).
+ draw_grid(20,20,0,0,false,false,col3,0.4f,0xCCCCCCCC,0xCCCCCCCC).
+ draw_text(5,5,"Iteration %d",col3,0,1,13,iteration).display(disp);
+ }
+ if (!(iteration%60)) img.distance_eikonal(1,3);
+ if (disp.is_resized()) disp.resize();
+ }
+
+ return 0;
+}