gmsh模块界面

这个界面是用PySide来写的，Pyside是QT的python绑定，具体代码在task_mesh_gmsh.py文件中。目前这个界面非常的捡漏，没有对接gmsh稍微高级一点的功能。界面对应的事件处理是在gmshtools.py中。这里只分析“gmsh version”与“Apply”运行gmsh功能。

def get_gmsh_command(self):
        from platform import system
        gmsh_std_location = FreeCAD.ParamGet(
            "User parameter:BaseApp/Preferences/Mod/Fem/Gmsh"
        ).GetBool("UseStandardGmshLocation")
        Console.PrintError("UseStandardGmshLocation = ".format(gmsh_std_location))
        if gmsh_std_location:
            if system() == "Windows": # windows 
                gmsh_path = FreeCAD.getHomePath() + "bin/gmsh.exe"
                FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Fem/Gmsh").SetString(
                    "gmshBinaryPath", gmsh_path
                )
                self.gmsh_bin = gmsh_path
            elif system() == "Linux":
                p1 = subprocess.Popen(["which", "gmsh"], stdout=subprocess.PIPE)
                if p1.wait() == 0:
                    output = p1.stdout.read()
                    output = output.decode("utf-8")
                    gmsh_path = output.split("\n")[0]
                elif p1.wait() == 1:
                    error_message = (
                        "Gmsh binary gmsh not found in standard system binary path. "
                        "Please install Gmsh or set path to binary "
                        "in FEM preferences tab Gmsh.\n"
                    )
                    Console.PrintError(error_message)
                    raise GmshError(error_message)
                self.gmsh_bin = gmsh_path
            elif system() == "Darwin":
                # https://forum.freecad.org/viewtopic.php?f=13&t=73041&p=642026#p642022
                gmsh_path = "/Applications/Gmsh.app/Contents/MacOS/gmsh"
                FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Fem/Gmsh").SetString(
                    "gmshBinaryPath", gmsh_path
                )
                self.gmsh_bin = gmsh_path
            else:
                error_message = (
                    "No standard location implemented for your operating system. "
                    "Set GMHS binary path in FEM preferences.\n"
                )
                Console.PrintError(error_message)
                raise GmshError(error_message)
        else:
            if not self.gmsh_bin:
                self.gmsh_bin = FreeCAD.ParamGet(
                    "User parameter:BaseApp/Preferences/Mod/Fem/Gmsh"
                ).GetString("gmshBinaryPath", "")
                Console