added SetPythonHome function (i.e. to use with OSGEO4W where python dll dir is not the same as PythonHome)

Author: Idan Miara

PythonForDelphi/Components/Sources/Core/PythonEngine.pas

@@ -1968,6 +1968,10 @@   TPythonInterface=class(TDynamicDll)
     Py_GetCopyright                 : function : PAnsiChar; cdecl;
     Py_GetExecPrefix                : function : PAnsiChar; cdecl;
     Py_GetPath                      : function : PAnsiChar; cdecl;
+    Py_SetPythonHome                : procedure (home : PAnsiChar); cdecl;
+    Py_GetPythonHome                : function : PAnsiChar; cdecl;
+    Py_SetPythonHome3000            : procedure (home : PWideChar); cdecl;
+    Py_GetPythonHome3000            : function : PWideChar; cdecl;
     Py_GetPrefix                    : function : PAnsiChar; cdecl;
     Py_GetProgramName               : function : PAnsiChar; cdecl;
 
@@ -2187,6 +2191,8 @@   TPythonEngine = class(TPythonInterface)
     FAutoFinalize:               Boolean;
     FProgramName:                AnsiString;
     FProgramNameW:               UnicodeString;
+    FPythonHome:                 AnsiString;
+    FPythonHomeW:                UnicodeString;
     FInitThreads:                Boolean;
     FOnPathInitialization:       TPathInitializationEvent;
     FOnSysPathInit:              TSysPathInitEvent;
@@ -2240,6 +2246,7 @@   TPythonEngine = class(TPythonInterface)
     procedure  Finalize;
     procedure  Lock;
     procedure  Unlock;
+    procedure  SetPythonHome(PythonHome: String);
     function   IsType(ob: PPyObject; obt: PPyTypeObject): Boolean;
     function   GetAttrString(obj: PPyObject; AName: PAnsiChar):PAnsiChar;
     function   CleanString(const s : AnsiString) : AnsiString;
@@ -4056,6 +4063,14 @@ procedure TPythonInterface.MapDll;
   Py_GetCopyright            :=Import('Py_GetCopyright');
   Py_GetExecPrefix           :=Import('Py_GetExecPrefix');
   Py_GetPath                 :=Import('Py_GetPath');
+  if IsPython3000 then
+    Py_SetPythonHome3000     :=Import('Py_SetPythonHome')
+  else
+    Py_SetPythonHome         :=Import('Py_SetPythonHome');
+  if IsPython3000 then
+    Py_GetPythonHome3000     :=Import('Py_GetPythonHome')
+  else
+    Py_GetPythonHome         :=Import('Py_GetPythonHome');
   Py_GetPrefix               :=Import('Py_GetPrefix');
   Py_GetProgramName          :=Import('Py_GetProgramName');
   PyParser_SimpleParseString :=Import('PyParser_SimpleParseString');
@@ -4850,6 +4865,12 @@ procedure TPythonEngine.Initialize;
     end
   end;
   AssignPyFlags;
+  if FPythonHomeW<>'' then begin
+    if IsPython3000 then
+      Py_SetPythonHome3000(PChar(FPythonHomeW))
+    else
+      Py_SetPythonHome(PAnsiChar(FPythonHome));
+  end;
   Py_Initialize;
   FInitialized := True;
   FIORedirected := False;
@@ -5111,6 +5132,12 @@ procedure TPythonEngine.SetPyFlags(const Value: TPythonFlags);
   end; // of if
 end;
 
+procedure TPythonEngine.SetPythonHome(PythonHome: String);
+begin
+  FPythonHomeW := PythonHome;
+  FPythonHome := UTF8Encode(PythonHome);
+end;
+
 function TPythonEngine.IsType(ob: PPyObject; obt: PPyTypeObject): Boolean;
 begin
   result := ob^.ob_type = obt;