fix segfault on exit with python3

.clang-format

@@ -0,0 +1,83 @@
+AccessModifierOffset: -4
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: None
+AlignConsecutiveBitFields: None
+AlignConsecutiveDeclarations: None
+AlignConsecutiveMacros: AcrossEmptyLinesAndComments
+AlignEscapedNewlines: Right
+AlignTrailingComments: false
+AllowAllArgumentsOnNextLine: true
+AllowAllParametersOfDeclarationOnNextLine: true
+AllowShortBlocksOnASingleLine: Always
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortEnumsOnASingleLine: true
+AllowShortFunctionsOnASingleLine: Inline
+AllowShortIfStatementsOnASingleLine: true
+AllowShortLambdasOnASingleLine: All
+AllowShortLoopsOnASingleLine: true
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: false
+AlwaysBreakTemplateDeclarations: true
+BinPackArguments: true
+BinPackParameters: true
+BitFieldColonSpacing: Both
+BreakBeforeBraces: Custom
+BraceWrapping:
+  AfterCaseLabel: false
+  AfterClass: true
+  AfterFunction: true
+  AfterControlStatement: false
+  SplitEmptyFunction: false
+  AfterEnum: false
+  AfterNamespace: true
+  AfterStruct: true
+  AfterUnion: false
+  AfterExternBlock: false
+  BeforeCatch: true
+  BeforeElse: true
+  BeforeLambdaBody: false
+  BeforeWhile: true
+  SplitEmptyRecord: false
+  SplitEmptyNamespace: false
+BreakBeforeBinaryOperators: All
+BreakBeforeConceptDeclarations: false
+BreakBeforeTernaryOperators: true
+BreakConstructorInitializers: BeforeColon
+BreakInheritanceList: BeforeColon
+BreakStringLiterals: true
+ColumnLimit: 80
+CompactNamespaces: false
+Cpp11BracedListStyle: true
+DerivePointerAlignment: false
+EmptyLineBeforeAccessModifier: Never
+FixNamespaceComments: true
+IncludeBlocks: Merge
+IndentCaseLabels: false
+IndentExternBlock: Indent
+IndentRequires: false
+IndentWidth: 4
+IndentWrappedFunctionNames: false
+KeepEmptyLinesAtTheStartOfBlocks: false
+NamespaceIndentation: All
+PointerAlignment: Left
+SortUsingDeclarations: true
+SpaceAfterCStyleCast: false
+SpaceAfterLogicalNot: false
+SpaceAfterTemplateKeyword: false
+SpaceAroundPointerQualifiers: Default
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeCaseColon: false
+SpaceBeforeCpp11BracedList: false
+SpaceBeforeCtorInitializerColon: true
+SpaceBeforeInheritanceColon: true
+SpaceBeforeParens: Never
+SpaceBeforeRangeBasedForLoopColon: true
+SpaceBeforeSquareBrackets: false
+SpaceInEmptyBlock: false
+SpaceInEmptyParentheses: false
+SpacesInCStyleCastParentheses: false
+SpacesInConditionalStatement: false
+SpacesInContainerLiterals: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+UseTab: Never

CMakeLists.txt

@@ -5,7 +5,6 @@ include(GNUInstallDirs)
 set(PACKAGE_NAME matplotlib_cpp)
 set(INSTALL_CONFIGDIR ${CMAKE_INSTALL_LIBDIR}/${PACKAGE_NAME}/cmake)
 
-
 # Library target
 add_library(matplotlib_cpp INTERFACE)
 target_include_directories(matplotlib_cpp
@@ -100,6 +99,22 @@ if(Python3_NumPy_FOUND)
   add_executable(spy examples/spy.cpp)
   target_link_libraries(spy PRIVATE matplotlib_cpp)
   set_target_properties(spy PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin")
+
+  add_executable(span examples/span.cpp)
+  target_link_libraries(span PRIVATE matplotlib_cpp)
+  target_compile_features(span PRIVATE cxx_std_20)
+  set_target_properties(span PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin")
+
+  add_executable(ranges examples/ranges.cpp)
+  target_link_libraries(ranges PRIVATE matplotlib_cpp)
+  target_compile_features(ranges PRIVATE cxx_std_20)
+  set_target_properties(ranges PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin")
+
+  add_executable(timeseries examples/timeseries.cpp)
+  target_link_libraries(timeseries PRIVATE matplotlib_cpp)
+  target_compile_features(timeseries PRIVATE cxx_std_20)
+  set_target_properties(timeseries PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin")
+
 endif()
 
 

datetime_utils.h

@@ -0,0 +1,138 @@
+#pragma once
+
+#include "matplotlibcpp.h"
+#include <Python.h>
+#include <chrono>
+#include <cstdlib>
+#include <datetime.h>
+#include <map>
+#include <ranges>
+#include <string>
+
+// Convenience functions for converting C/C++ time objects to datetime.datetime
+// objects. These are outside the matplotlibcpp namespace because they do not
+// exist in matplotlib.pyplot.
+template<class TimePoint>
+PyObject* toPyDateTime(const TimePoint& t, int dummy = 0)
+{
+    using namespace std::chrono;
+    auto tsec = time_point_cast<seconds>(t);
+    auto us = duration_cast<microseconds>(t - tsec);
+
+    time_t tt = system_clock::to_time_t(t);
+    PyObject* obj = toPyDateTime(tt, us.count());
+
+    return obj;
+}
+
+template<>
+PyObject* toPyDateTime(const time_t& t, int us)
+{
+    tm tm{};
+    gmtime_r(&t, &tm); // compatible with matlab, inverse of datenum.
+
+    if(!PyDateTimeAPI) { PyDateTime_IMPORT; }
+
+    PyObject* obj = PyDateTime_FromDateAndTime(tm.tm_year + 1900, tm.tm_mon + 1,
+                                               tm.tm_mday, tm.tm_hour,
+                                               tm.tm_min, tm.tm_sec, us);
+    if(obj) {
+        PyDateTime_Check(obj);
+        Py_INCREF(obj);
+    }
+
+    return obj;
+}
+
+template<class Time_t>
+PyObject* toPyDateTimeList(const Time_t* t, size_t nt)
+{
+    PyObject* tlist = PyList_New(nt);
+    if(tlist == nullptr) return nullptr;
+
+    if(!PyDateTimeAPI) { PyDateTime_IMPORT; }
+
+    for(size_t i = 0; i < nt; i++) {
+        PyObject* ti = toPyDateTime(t[i], 0);
+        PyList_SET_ITEM(tlist, i, ti);
+    }
+
+    return tlist;
+}
+
+template<class Time_t>
+class DateTimeList
+{
+public:
+
+    DateTimeList() = default;
+
+    DateTimeList(const Time_t* t, size_t nt)
+    {
+        matplotlibcpp::detail::_interpreter::get();
+        tlist = (PyListObject*)toPyDateTimeList(t, nt);
+    }
+
+    ~DateTimeList()
+    {
+        if(tlist) Py_DECREF((PyObject*)tlist);
+    }
+
+    DateTimeList& operator=(const DateTimeList& rhs) {
+        tlist=rhs.tlist;
+        Py_INCREF(tlist);
+        return *this;
+    }
+
+    PyListObject* get() const { return tlist; }
+    size_t size() const { return tlist ? PyList_Size((PyObject*)tlist) : 0; }
+private:
+    mutable PyListObject* tlist = nullptr;
+};
+
+namespace matplotlibcpp
+{
+    // special purpose function to plot against python datetime objects.
+    template<class Time_t, std::ranges::contiguous_range ContainerY>
+    bool plot(const DateTimeList<Time_t>& t, const ContainerY& y,
+              const std::string& fmt = "")
+    {
+        detail::_interpreter::get();
+
+        // DECREF decrements the ref counts of all objects in the plot_args
+        // tuple, In particular, it decreasesthe ref count of the time array x.
+        // We want to maintain that unchanged though, so we can reuse it.
+        PyListObject* tarray = t.get();
+        Py_INCREF(tarray);
+
+        NPY_TYPES ytype
+            = detail::select_npy_type<typename ContainerY::value_type>::type;
+
+        npy_intp tsize = PyList_Size((PyObject*)tarray);
+        assert(y.size() % tsize == 0
+               && "length of y must be a multiple of length of x!");
+
+        npy_intp yrows = tsize, ycols = y.size() / yrows;
+        npy_intp ysize[] = {yrows, ycols}; // ysize[0] must equal tsize
+
+        PyObject* yarray = PyArray_New(&PyArray_Type, 2, ysize, ytype, nullptr,
+                                       (void*)y.data(), 0, NPY_ARRAY_FARRAY,
+                                       nullptr); // col major
+
+        PyObject* pystring = PyString_FromString(fmt.c_str());
+
+        PyObject* plot_args = PyTuple_New(3);
+        PyTuple_SetItem(plot_args, 0, (PyObject*)tarray);
+        PyTuple_SetItem(plot_args, 1, yarray);
+        PyTuple_SetItem(plot_args, 2, pystring);
+
+        PyObject* res = PyObject_CallObject(
+            detail::_interpreter::get().s_python_function_plot, plot_args);
+
+        Py_DECREF(plot_args);
+        if(res) Py_DECREF(res);
+
+        return true;
+    }
+
+} // namespace matplotlibcpp

examples/animation.cpp

@@ -1,3 +1,7 @@
+//
+// g++ -g -Wall -o animation $(python-config --includes) animation.cpp $(python-config --ldflags --embed)
+//
+
 #define _USE_MATH_DEFINES
 #include <cmath>
 #include "../matplotlibcpp.h"
@@ -6,31 +10,34 @@ namespace plt = matplotlibcpp;
 
 int main()
 {
-	int n = 1000;
-	std::vector<double> x, y, z;
-
-	for(int i=0; i<n; i++) {
-		x.push_back(i*i);
-		y.push_back(sin(2*M_PI*i/360.0));
-		z.push_back(log(i));
-
-		if (i % 10 == 0) {
-			// Clear previous plot
-			plt::clf();
-			// Plot line from given x and y data. Color is selected automatically.
-			plt::plot(x, y);
-			// Plot a line whose name will show up as "log(x)" in the legend.
-			plt::named_plot("log(x)", x, z);
-
-			// Set x-axis to interval [0,1000000]
-			plt::xlim(0, n*n);
-
-			// Add graph title
-			plt::title("Sample figure");
-			// Enable legend.
-			plt::legend();
-			// Display plot continuously
-			plt::pause(0.01);
-		}
+    int n = 1000;
+    std::vector<double> x, y, z;
+
+    for(int i=0; i<n; i++) {
+	x.push_back(i*i);
+	y.push_back(sin(2*M_PI*i/360.0));
+	z.push_back(log(i));
+
+	if (i % 10 == 0) {
+	    // Clear previous plot
+	    plt::clf();
+	    // Plot line from given x and y data. Color is selected automatically.
+	    plt::plot(x, y);
+	    // Plot a line whose name will show up as "log(x)" in the legend.
+	    plt::named_plot("log(x)", x, z);
+
+	    // Set x-axis to interval [0,1000000]
+	    plt::xlim(0, n*n);
+
+	    // Add graph title
+	    plt::title("Sample figure");
+	    // Enable legend.
+	    plt::legend();
+	    // Display plot continuously
+	    plt::pause(0.01);
 	}
+    }
+
+    plt::detail::_interpreter::kill();
+    return 0;
 }

examples/bar.cpp

@@ -1,3 +1,7 @@
+//
+// g++ -g -Wall -o bar $(python-config --includes) bar.cpp $(python-config --ldflags --embed)
+//
+
 #define _USE_MATH_DEFINES
 
 #include <iostream>
@@ -14,5 +18,6 @@ int main(int argc, char **argv) {
     plt::bar(test_data);
     plt::show();
 
+    plt::detail::_interpreter::kill();
     return (0);
 }

examples/basic.cpp

@@ -1,11 +1,16 @@
+//
+// g++ -g -Wall -std=c++20 -o basic -I/usr/include/python3.9 basic.cpp -lpython3.9
+// g++ -g -Wall -std=c++20 -o basic $(python-config --includes) basic.cpp $(python-config --ldflags --embed)
+//
+
 #define _USE_MATH_DEFINES
 #include <iostream>
 #include <cmath>
 #include "../matplotlibcpp.h"
 
 namespace plt = matplotlibcpp;
 
-int main() 
+int main()
 {
     // Prepare data.
     int n = 5000;
@@ -15,7 +20,7 @@ int main()
         y.at(i) = sin(2*M_PI*i/360.0);
         z.at(i) = log(i);
     }
-    
+
     // Set the size of output image = 1200x780 pixels
     plt::figure_size(1200, 780);
 
@@ -41,4 +46,7 @@ int main()
     const char* filename = "./basic.png";
     std::cout << "Saving result to " << filename << std::endl;;
     plt::save(filename);
+
+    plt::detail::_interpreter::kill();
+    return 0;
 }

examples/colorbar.cpp

@@ -1,3 +1,7 @@
+//
+// g++ -g -Wall -o colorbar $(python-config --includes) colorbar.cpp $(python-config --ldflags --embed)
+//
+
 #define _USE_MATH_DEFINES
 #include <cmath>
 #include <iostream>
@@ -29,4 +33,7 @@ int main()
     plt::show();
     plt::close();
     Py_DECREF(mat);
+
+    plt::detail::_interpreter::kill();
+    return 0;
 }