[教學]C++/MFC - SetDisplayConfig @ 一個小小工程師的心情抒發天地

測試程式，
拿來測試工作上會用到的東西。

pch.h

#ifndef PCH_H
#define PCH_H

// TODO: add headers that you want to pre-compile here

enum class DisplayTopology
{
   Internal,
   Clone,
   Extend,
   External,
   Error
};

DisplayTopology GetDisplayTopology();
bool SetDisplayTopology(DisplayTopology topology);

#endif //PCH_H

pch.cpp

// pch.cpp: source file corresponding to pre-compiled header; necessary for compilation to succeed

#include "pch.h"

// In general, ignore this file, but keep it around if you are using pre-compiled headers.

#include <ciso646>
#include <windows.h>

#pragma comment(lib,"User32.lib")

//-------------------------------------------------------------------------------------------------
DisplayTopology GetDisplayTopology()
{
UINT32 numPathArrayElements;
UINT32 numModeInfoArrayElements;

GetDisplayConfigBufferSizes(QDC_DATABASE_CURRENT, &numPathArrayElements, &numModeInfoArrayElements);

auto pathArray = new DISPLAYCONFIG_PATH_INFO[numPathArrayElements];
auto modeInfoArray = new DISPLAYCONFIG_MODE_INFO[numModeInfoArrayElements];

DISPLAYCONFIG_TOPOLOGY_ID currentTopologyId;

   auto ok = QueryDisplayConfig(QDC_DATABASE_CURRENT,
       &numPathArrayElements, pathArray,
       &numModeInfoArrayElements, modeInfoArray,
       &currentTopologyId);

delete[] pathArray;
delete[] modeInfoArray;

   if (ok == ERROR_SUCCESS) switch (currentTopologyId)
   {
   case DISPLAYCONFIG_TOPOLOGY_INTERNAL: return DisplayTopology::Internal;
   case DISPLAYCONFIG_TOPOLOGY_CLONE: return DisplayTopology::Clone;
   case DISPLAYCONFIG_TOPOLOGY_EXTEND: return DisplayTopology::Extend;
   case DISPLAYCONFIG_TOPOLOGY_EXTERNAL: return DisplayTopology::External;
   default: break;
   }
   return DisplayTopology::Error;
}

//-------------------------------------------------------------------------------------------------
bool SetDisplayTopology(DisplayTopology topology)
{
   UINT32 topologies[] =
   {
   SDC_TOPOLOGY_INTERNAL,
   SDC_TOPOLOGY_CLONE,
   SDC_TOPOLOGY_EXTEND,
   SDC_TOPOLOGY_EXTERNAL
   };
   if (topology == DisplayTopology::Error) return false;
   return SetDisplayConfig(0, NULL, 0, NULL, topologies[(int)topology] | SDC_APPLY) == ERROR_SUCCESS;
}

Main

#include "pch.h"
#include <cctype>
#include <iostream>
#include <string>
using namespace std;

//-------------------------------------------------------------------------------------------------
void set_topology(std::string&& mode)
{
   for (auto& c : mode) c = std::tolower(c & 0x7F);
   DisplayTopology topology =
       (mode == "internal") ? DisplayTopology::Internal :
       (mode == "clone") ? DisplayTopology::Clone :
       (mode == "duplicate") ? DisplayTopology::Clone :
       (mode == "extend") ? DisplayTopology::Extend :
       (mode == "external") ? DisplayTopology::External :
       DisplayTopology::Error;

if (topology == DisplayTopology::Error) throw "Argument must be one of 'internal', 'clone', 'duplicate', 'extend', or 'external'";
if (!SetDisplayTopology(topology)) throw "Could not change display topology";
}

//-------------------------------------------------------------------------------------------------
void get_topology()
{
   static const char* topologies[] =
   {
   "internal",
   "clone",
   "extend",
   "external",
   nullptr
   };
   auto topology = topologies[(int)GetDisplayTopology()];
   if (!topology) throw "Failure to identify the current display topology";
   std::cout << topology << "\n";
}

//-------------------------------------------------------------------------------------------------
int main()
{

   try
   {
       int nSel = -1 ;
       while (1)
       {
           cout << "Select a Mode : " << endl
               << "1 = internal" << endl
               << "2 = clone" << endl
               << "3 = extend" << endl
               << "4 = external" << endl;
           cin >> nSel;
           if (nSel < 0 || nSel>4)
           {
               cout << endl;
               continue;
           }
           else
           {
               switch (nSel)
               {
               case 1:set_topology("internal"); break;
               case 2:set_topology("clone"); break;
               case 3:set_topology("extend"); break;
               case 4:set_topology("external"); break;
               default:
                   break;
               }
           }