Legend

legend({str1,str2,str3}); 

Plot

C++

#include <cmath> #include <matplot/matplot.h> int main() {  using namespace matplot;  std::vector<double> x = linspace(0, pi);  std::vector<double> y1 = transform(x, [](auto x) { return cos(x); });  plot(x, y1);  hold(on);  std::vector<double> y2 = transform(x, [](auto x) { return cos(2 * x); });  plot(x, y2);  ::matplot::legend({"cos(x)", "cos(2x)"});  std::vector<double> y3 = transform(x, [](auto x) { return cos(3 * x); });  auto p = plot(x, y3);  p->display_name("cos(3x)");  hold(off);  show();  ::matplot::legend(off);  show();  return 0; } 

More examples

Plot

C++

#include <cmath> #include <matplot/matplot.h> int main() {  using namespace matplot;  tiledlayout(2, 1);  auto y1 = rand(3, 3, 0, 1);  auto ax1 = nexttile();  plot(y1);  auto y2 = rand(3, 3, 0, 1);  auto ax2 = nexttile();  plot(y2);  ::matplot::legend(ax1, {"Line 1", "Line 2", "Line 3"});  show();  return 0; } 

Plot

C++

#include <cmath> #include <matplot/matplot.h> int main() {  using namespace matplot;  auto x = linspace(0, pi);  auto y1 = transform(x, [](double x) { return cos(x); });  auto y2 = transform(x, [](double x) { return cos(2 * x); });  auto p1 = plot(x, y1);  p1->display_name("cos(x)");  hold(on);  auto p2 = plot(x, y2);  p2->display_name("cos(2x)");  hold(off);  ::matplot::legend({});  show();  return 0; } 

Plot

C++

#include <cmath> #include <matplot/matplot.h> int main() {  using namespace matplot;  auto x = linspace(0, pi);  auto y1 = transform(x, [](double x) { return cos(x); });  auto y2 = transform(x, [](double x) { return cos(2 * x); });  auto y3 = transform(x, [](double x) { return cos(3 * x); });  auto y4 = transform(x, [](double x) { return cos(4 * x); });  plot(x, y1);  hold(on);  plot(x, y2);  plot(x, y3);  plot(x, y4);  hold(off);  auto l = ::matplot::legend({"cos(x)", "cos(2x)", "cos(3x)", "cos(4x)"});  l->location(legend::general_alignment::topleft);  l->num_rows(2);  show();  return 0; } 

Plot

C++

#include <cmath> #include <matplot/matplot.h> int main() {  using namespace matplot;  auto x = linspace(0, pi);  auto y1 = transform(x, [](double x) { return cos(x); });  auto y2 = transform(x, [](double x) { return cos(2 * x); });  auto y3 = transform(x, [](double x) { return cos(3 * x); });  auto p1 = plot(x, y1);  hold(on);  plot(x, y2);  auto p3 = plot(x, y3);  hold(off);  ::matplot::legend({p1, p3}, {"First", "Third"});  show();  return 0; } 

Plot

C++

#include <cmath> #include <matplot/matplot.h> int main() {  using namespace matplot;  auto x = linspace(0, pi);  auto y1 = transform(x, [](double x) { return cos(x); });  auto y2 = transform(x, [](double x) { return cos(2 * x); });  plot(x, y1);  hold(on);  plot(x, y2);  hold(off);  auto lgd = ::matplot::legend({"cos(x)", "cos(2x)"});  title(lgd, "My legend title");  show();  return 0; } 

Plot

C++

#include <cmath> #include <matplot/matplot.h> int main() {  using namespace matplot;  auto x = linspace(0, pi);  auto y1 = transform(x, [](double x) { return cos(x); });  auto y2 = transform(x, [](double x) { return cos(2 * x); });  plot(x, y1);  hold(on);  plot(x, y2);  hold(off);  auto lgd = ::matplot::legend({"cos(x)", "cos(2x)"});  lgd->location(legend::general_alignment::bottomleft);  lgd->box(false);  show();  return 0; } 

Plot

C++

#include <matplot/matplot.h> int main() {  using namespace matplot;  auto rdm = rand(4, 4, 0, 1);  plot(rdm);  auto lgd = ::matplot::legend({"Line 1", "Line 2", "Line 3", "Line 4"});  lgd->font_size(12);  lgd->text_color("blue");  lgd->num_columns(2);  show();  return 0; }