matplotlib/src/_tkagg.cpp at main · quantfns/matplotlib · GitHub

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/* -*- mode: c++; c-basic-offset: 4 -*- */

// Where is PIL?

// Many years ago, Matplotlib used to include code from PIL (the Python Imaging

// Library). Since then, the code has changed a lot - the organizing principle

// and methods of operation are now quite different. Because our review of

// the codebase showed that all the code that came from PIL was removed or

// rewritten, we have removed the PIL licensing information. If you want PIL,

// you can get it at https://python-pillow.org/

#define PY_SSIZE_T_CLEAN

#include <Python.h>

#ifdef _WIN32

#define WIN32_DLL

#endif

#ifdef __CYGWIN__

* Unfortunately cygwin's libdl inherits restrictions from the underlying

* Windows OS, at least currently. Therefore, a symbol may be loaded from a

* module by dlsym() only if it is really located in the given module,

* dependencies are not included. So we have to use native WinAPI on Cygwin

* also.

#define WIN32_DLL

static inline PyObject *PyErr_SetFromWindowsErr(int ierr) {

PyErr_SetString(PyExc_OSError, "Call to EnumProcessModules failed");

return NULL;

}

#endif

#ifdef WIN32_DLL

#include <string>

#include <windows.h>

#include <commctrl.h>

#define PSAPI_VERSION 1

#include <psapi.h> // Must be linked with 'psapi' library

#define dlsym GetProcAddress

#else

#include <dlfcn.h>

#endif

// Include our own excerpts from the Tcl / Tk headers

#include "_tkmini.h"

static int convert_voidptr(PyObject *obj, void *p)

{

void **val = (void **)p;

*val = PyLong_AsVoidPtr(obj);

return *val != NULL ? 1 : !PyErr_Occurred();

}

// Global vars for Tk functions. We load these symbols from the tkinter

// extension module or loaded Tk libraries at run-time.

static Tk_FindPhoto_t TK_FIND_PHOTO;

static Tk_PhotoPutBlock_t TK_PHOTO_PUT_BLOCK;

// Global vars for Tcl functions. We load these symbols from the tkinter

// extension module or loaded Tcl libraries at run-time.

static Tcl_SetVar_t TCL_SETVAR;

static PyObject *mpl_tk_blit(PyObject *self, PyObject *args)

{

Tcl_Interp *interp;

char const *photo_name;

int height, width;

unsigned char *data_ptr;

int comp_rule;

int put_retval;

int o0, o1, o2, o3;

int x1, x2, y1, y2;

Tk_PhotoHandle photo;

Tk_PhotoImageBlock block;

if (!PyArg_ParseTuple(args, "O&s(iiO&)i(iiii)(iiii):blit",

convert_voidptr, &interp, &photo_name,

&height, &width, convert_voidptr, &data_ptr,

&comp_rule,

&o0, &o1, &o2, &o3,

&x1, &x2, &y1, &y2)) {

goto exit;

}

if (!(photo = TK_FIND_PHOTO(interp, photo_name))) {

PyErr_SetString(PyExc_ValueError, "Failed to extract Tk_PhotoHandle");

goto exit;

}

if (0 > y1 || y1 > y2 || y2 > height || 0 > x1 || x1 > x2 || x2 > width) {

PyErr_SetString(PyExc_ValueError, "Attempting to draw out of bounds");

goto exit;

}

if (comp_rule != TK_PHOTO_COMPOSITE_OVERLAY && comp_rule != TK_PHOTO_COMPOSITE_SET) {

PyErr_SetString(PyExc_ValueError, "Invalid comp_rule argument");

goto exit;

}

Py_BEGIN_ALLOW_THREADS

block.pixelPtr = data_ptr + 4 * ((height - y2) * width + x1);

block.width = x2 - x1;

block.height = y2 - y1;

block.pitch = 4 * width;

block.pixelSize = 4;

block.offset[0] = o0;

block.offset[1] = o1;

block.offset[2] = o2;

block.offset[3] = o3;

put_retval = TK_PHOTO_PUT_BLOCK(

interp, photo, &block, x1, height - y2, x2 - x1, y2 - y1, comp_rule);

Py_END_ALLOW_THREADS

if (put_retval == TCL_ERROR) {

return PyErr_NoMemory();

}

exit:

if (PyErr_Occurred()) {

return NULL;

} else {

Py_RETURN_NONE;

}

#ifdef WIN32_DLL

LRESULT CALLBACK

DpiSubclassProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam,

UINT_PTR uIdSubclass, DWORD_PTR dwRefData)

{

switch (uMsg) {

case WM_DPICHANGED:

// This function is a subclassed window procedure, and so is run during

// the Tcl/Tk event loop. Unfortunately, Tkinter has a *second* lock on

// Tcl threading that is not exposed publicly, but is currently taken

// while we're in the window procedure. So while we can take the GIL to

// call Python code, we must not also call *any* Tk code from Python.

// So stay with Tcl calls in C only.

{

// This variable naming must match the name used in

// lib/matplotlib/backends/_backend_tk.py:FigureManagerTk.

std::string var_name("window_dpi");

var_name += std::to_string((unsigned long long)hwnd);

// X is high word, Y is low word, but they are always equal.

std::string dpi = std::to_string(LOWORD(wParam));

Tcl_Interp* interp = (Tcl_Interp*)dwRefData;

TCL_SETVAR(interp, var_name.c_str(), dpi.c_str(), 0);

}

return 0;

case WM_NCDESTROY:

RemoveWindowSubclass(hwnd, DpiSubclassProc, uIdSubclass);

break;

}

return DefSubclassProc(hwnd, uMsg, wParam, lParam);

}

#endif

static PyObject*

mpl_tk_enable_dpi_awareness(PyObject* self, PyObject*const* args,

Py_ssize_t nargs)

{

if (nargs != 2) {

return PyErr_Format(PyExc_TypeError,

"enable_dpi_awareness() takes 2 positional "

"arguments but %zd were given",

nargs);

}

#ifdef WIN32_DLL

HWND frame_handle = NULL;

Tcl_Interp *interp = NULL;

if (!convert_voidptr(args[0], &frame_handle)) {

return NULL;

}

if (!convert_voidptr(args[1], &interp)) {

return NULL;

}

#ifdef _DPI_AWARENESS_CONTEXTS_

HMODULE user32 = LoadLibrary("user32.dll");

typedef DPI_AWARENESS_CONTEXT (WINAPI *GetWindowDpiAwarenessContext_t)(HWND);

GetWindowDpiAwarenessContext_t GetWindowDpiAwarenessContextPtr =

(GetWindowDpiAwarenessContext_t)GetProcAddress(

user32, "GetWindowDpiAwarenessContext");

if (GetWindowDpiAwarenessContextPtr == NULL) {

FreeLibrary(user32);

Py_RETURN_FALSE;

}

typedef BOOL (WINAPI *AreDpiAwarenessContextsEqual_t)(DPI_AWARENESS_CONTEXT,

DPI_AWARENESS_CONTEXT);

AreDpiAwarenessContextsEqual_t AreDpiAwarenessContextsEqualPtr =

(AreDpiAwarenessContextsEqual_t)GetProcAddress(

user32, "AreDpiAwarenessContextsEqual");

if (AreDpiAwarenessContextsEqualPtr == NULL) {

FreeLibrary(user32);

Py_RETURN_FALSE;

}

DPI_AWARENESS_CONTEXT ctx = GetWindowDpiAwarenessContextPtr(frame_handle);

bool per_monitor = (

AreDpiAwarenessContextsEqualPtr(

ctx, DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2) ||

AreDpiAwarenessContextsEqualPtr(

ctx, DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE));

if (per_monitor) {

// Per monitor aware means we need to handle WM_DPICHANGED by wrapping

// the Window Procedure, and the Python side needs to trace the Tk

// window_dpi variable stored on interp.

SetWindowSubclass(frame_handle, DpiSubclassProc, 0, (DWORD_PTR)interp);

}

FreeLibrary(user32);

return PyBool_FromLong(per_monitor);

#endif

Py_RETURN_NONE;

}

static PyMethodDef functions[] = {

{ "blit", (PyCFunction)mpl_tk_blit, METH_VARARGS },

{ "enable_dpi_awareness", (PyCFunction)mpl_tk_enable_dpi_awareness,

METH_FASTCALL },

{ NULL, NULL } /* sentinel */

};

// Functions to fill global Tcl/Tk function pointers by dynamic loading.

template <class T>

bool load_tcl_tk(T lib)

{

// Try to fill Tcl/Tk global vars with function pointers. Return whether

// all of them have been filled.

if (void* ptr = dlsym(lib, "Tcl_SetVar")) {

TCL_SETVAR = (Tcl_SetVar_t)ptr;

}

if (void* ptr = dlsym(lib, "Tk_FindPhoto")) {

TK_FIND_PHOTO = (Tk_FindPhoto_t)ptr;

}

if (void* ptr = dlsym(lib, "Tk_PhotoPutBlock")) {

TK_PHOTO_PUT_BLOCK = (Tk_PhotoPutBlock_t)ptr;

}

return TCL_SETVAR && TK_FIND_PHOTO && TK_PHOTO_PUT_BLOCK;

}

#ifdef WIN32_DLL

/* On Windows, we can't load the tkinter module to get the Tcl/Tk symbols,

* because Windows does not load symbols into the library name-space of

* importing modules. So, knowing that tkinter has already been imported by

* Python, we scan all modules in the running process for the Tcl/Tk function

* names.

void load_tkinter_funcs(void)

{

HANDLE process = GetCurrentProcess(); // Pseudo-handle, doesn't need closing.

HMODULE* modules = NULL;

DWORD size;

if (!EnumProcessModules(process, NULL, 0, &size)) {

PyErr_SetFromWindowsErr(0);

goto exit;

}

if (!(modules = static_cast<HMODULE*>(malloc(size)))) {

PyErr_NoMemory();

goto exit;

}

if (!EnumProcessModules(process, modules, size, &size)) {

PyErr_SetFromWindowsErr(0);

goto exit;

}

for (unsigned i = 0; i < size / sizeof(HMODULE); ++i) {

if (load_tcl_tk(modules[i])) {

return;

}

exit:

free(modules);

}

#else // not Windows

* On Unix, we can get the Tk symbols from the tkinter module, because tkinter

* uses these symbols, and the symbols are therefore visible in the tkinter

* dynamic library (module).

void load_tkinter_funcs(void)

{

// Load tkinter global funcs from tkinter compiled module.

void *main_program = NULL, *tkinter_lib = NULL;

PyObject *module = NULL, *py_path = NULL, *py_path_b = NULL;

char *path;

// Try loading from the main program namespace first.

main_program = dlopen(NULL, RTLD_LAZY);

if (load_tcl_tk(main_program)) {

goto exit;

}

// Clear exception triggered when we didn't find symbols above.

PyErr_Clear();

// Handle PyPy first, as that import will correctly fail on CPython.

module = PyImport_ImportModule("_tkinter.tklib_cffi"); // PyPy

if (!module) {

PyErr_Clear();

module = PyImport_ImportModule("_tkinter"); // CPython

}

if (!(module &&

(py_path = PyObject_GetAttrString(module, "__file__")) &&

(py_path_b = PyUnicode_EncodeFSDefault(py_path)) &&

(path = PyBytes_AsString(py_path_b)))) {

goto exit;

}

tkinter_lib = dlopen(path, RTLD_LAZY);

if (!tkinter_lib) {

PyErr_SetString(PyExc_RuntimeError, dlerror());

goto exit;

}

if (load_tcl_tk(tkinter_lib)) {

goto exit;

}

exit:

// We don't need to keep a reference open as the main program & tkinter

// have been imported. Use a non-short-circuiting "or" to try closing both

// handles before handling errors.

if ((main_program && dlclose(main_program))

| (tkinter_lib && dlclose(tkinter_lib))) {

PyErr_SetString(PyExc_RuntimeError, dlerror());

}

Py_XDECREF(module);

Py_XDECREF(py_path);

Py_XDECREF(py_path_b);

}

#endif // end not Windows

static PyModuleDef _tkagg_module = {

PyModuleDef_HEAD_INIT, "_tkagg", NULL, -1, functions

};

#pragma GCC visibility push(default)

PyMODINIT_FUNC PyInit__tkagg(void)

{

load_tkinter_funcs();

PyObject *type, *value, *traceback;

PyErr_Fetch(&type, &value, &traceback);

// Always raise ImportError (normalizing a previously set exception if

// needed) to interact properly with backend auto-fallback.

if (value) {

PyErr_NormalizeException(&type, &value, &traceback);

PyErr_SetObject(PyExc_ImportError, value);

return NULL;

} else if (!TCL_SETVAR) {

PyErr_SetString(PyExc_ImportError, "Failed to load Tcl_SetVar");

return NULL;

} else if (!TK_FIND_PHOTO) {

PyErr_SetString(PyExc_ImportError, "Failed to load Tk_FindPhoto");

return NULL;

} else if (!TK_PHOTO_PUT_BLOCK) {

PyErr_SetString(PyExc_ImportError, "Failed to load Tk_PhotoPutBlock");

return NULL;

}

return PyModule_Create(&_tkagg_module);

}

#pragma GCC visibility pop

matplotlib/src/_tkagg.cpp at main · quantfns/matplotlib · GitHub

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