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標題: 看不懂這些程式碼(關於C++) [打印本頁]

作者: flyinsky5 時間: 2009-5-12 03:14 PM 標題: 看不懂這些程式碼(關於C++)

這些程式碼我看不太懂
不知道有哪些好心的大大可以幫我解惑
也幫我註解一下....

#pragma comment (lib, "comctl32.lib")
#pragma comment (lib, "dxguid.lib")
#pragma comment (lib, "strmiids.lib")
#ifndef UNICODE
#define UNICODE
#endif
#include <windows.h>
#include <commctrl.h>
#include <dshow.h>
#include <cstdio>
extern"C" WINBASEAPI HWND WINAPI GetConsoleWindow();
#define MsgBox(s) MessageBox (0,s,0,MB_OK)
WCHAR e_str[256];
void cdecl MsgBox_ (wchar_t* fmt, ...)
{swprintf_s (e_str, 256, fmt, (char*)(&fmt+1)); MsgBox(e_str);}
namespace FileDlg
{
WCHAR title[256] = L"*.*";
WCHAR filter[256] =
      L"AVI File (*.avi)\0*.avi\0"
      L"MPEG File (*.mpg)\0*.mpg\0"
      L"Mp3 File (*.mp3)\0*.mp3\0"
      L"Wave File (*.wav)\0*.wav\0"
      L"All Files (*.*)\0*.*\0\0";
WCHAR file_name[512], init_dir[512], exe_path[512]={0}, *fname;
OPENFILENAME ofn = {
         sizeof(OPENFILENAME), 0, 0, (LPCWSTR)filter,0,0,1, title,
         512, file_name, 512, init_dir, 0, 6, 0,1, L"", 0,0,0
};
LPWSTR open (HWND hwnd)
{
      ofn.hwndOwner = hwnd;
      ofn.lpstrTitle = L"開檔";
      ofn.lpstrFilter  = filter;
      ofn.Flags       = 6;
      ofn.lpstrFile[0] = 0;    //若開檔後仍為0表示按了[Cancel]
      if (!GetOpenFileName (&ofn)) {
         if(*ofn.lpstrFile)
            MsgBox_ (L"Fail to open: %d", CommDlgExtendedError());
         return 0;
      }
      return fname = ofn.lpstrFile;    //取個短名字
}
}

#define DO(b) if (FAILED(b)) \
            {MsgBox_(L"fail in %s line %d",__FILE__,__LINE__);}

struct Player
{
bool bPlaying;
long evCode;
LONGLONG pos, duration;
IGraphBuilder* pGraph;
IMediaControl* pCtrl;
IVideoWindow*  pVideo;
IMediaSeeking* pSeek;
void init()
{
      bPlaying = false;
      DO (CoCreateInstance (CLSID_FilterGraph, 0, CLSCTX_INPROC,
                     IID_IGraphBuilder, (void**) &pGraph));
      DO (pGraph->QueryInterface (IID_IMediaControl, (void**) &pCtrl));
      DO (pGraph->QueryInterface (IID_IVideoWindow,  (void**) &pVideo));
      DO (pGraph->QueryInterface (IID_IMediaSeeking, (void**) &pSeek));
}
void free()
{
      if (bPlaying) {
         setTimeInfo (0);
         pCtrl->Stop();
      }
      pVideo->put_Visible (OAFALSE);
      pVideo->put_Owner (0);
      pSeek->Release();
      pCtrl->Release();
      pGraph->Release();
}
void run (WCHAR* path, HWND hwnd)
{
      bPlaying = true;
      DO (pGraph->RenderFile (path, 0));
      DO (pVideo->put_Owner ((OAHWND)hwnd));
      resize (hwnd);
      DO (pCtrl->Run());
}
void resize (HWND hwnd)
{
      if (!bPlaying) return;
      RECT rc; GetClientRect (hwnd, &rc);
      DO (pVideo->put_WindowStyle (WS_CHILD| WS_CLIPSIBLINGS));
      DO (pVideo->SetWindowPosition (0, 0, rc.right, rc.bottom-20));
}
void getTimeInfo()
{
      pSeek->GetCurrentPosition (&pos);
      pSeek->GetDuration (&duration);
}
void setTimeInfo (double pos_)
{
      LONGLONG duration = 1;
      pSeek->GetDuration (&duration);
      duration *= pos_;
      pSeek->SetPositions (&duration,
         AM_SEEKING_AbsolutePositioning,
         NULL, AM_SEEKING_NoPositioning);
}
void pause (bool b) {b?pCtrl->Pause():pCtrl->Run();}
};
//-------------------------- 主程式 -------------------------------
HINSTANCE  e_hInst;
LRESULT CALLBACK WndProc (HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
static enum {ID_TIMER, ID_OPEN, ID_PAUSE, ID_SLIDER};
static bool bPause;
static int w,h;
static Player player;
static HMENU  hMenu;
static HWND hSlider;          //scroll handle

switch (msg)
{
   case WM_CREATE:
         hMenu = (HMENU) CreateMenu();
         AppendMenu (hMenu, MF_STRING, ID_OPEN,  L"開檔");
         AppendMenu (hMenu, MF_STRING, ID_PAUSE, L"暫停");
         SetMenu (hwnd, hMenu);
         hSlider = CreateWindow (TRACKBAR_CLASS, L"",
                  WS_CHILD| WS_VISIBLE| TBS_AUTOTICKS, 216,4,256,16,
                  hwnd, (HMENU)ID_SLIDER, e_hInst, 0);
         SendMessage (hSlider, TBM_SETRANGE, TRUE, MAKELONG(1,1000));
         SendMessage (hSlider, TBM_SETPOS, TRUE, 1);
         return 0;
   case WM_CLOSE:
         if (player.bPlaying) {
            player.free();
            KillTimer (hwnd, ID_TIMER);
         }
         PostQuitMessage(0);
         return 0;
   case WM_SIZE:
         player.resize (hwnd);
         w = LOWORD (lParam);
         h = HIWORD (lParam);
         MoveWindow (hSlider, 2, h-20, w-4, 20, TRUE);
         return 0;
   case WM_KEYDOWN:
         switch (wParam) {
         case VK_ESCAPE:
               SendMessage (hwnd, WM_CLOSE, 0, 0); break;
         case VK_RETURN:
               player.pause (bPause = !bPause); break;
         }
         return 0;
   case WM_HSCROLL:
         player.setTimeInfo (
            double(SendMessage (hSlider, TBM_GETPOS, 0, 0))/1000);
         return 0;
   case WM_TIMER:
         player.getTimeInfo();
         SendMessage (hSlider, TBM_SETPOS, TRUE,
            player.pos * 1000 / player.duration);
         return 0;
   case WM_COMMAND:
         if (ID_OPEN == LOWORD(wParam)) {
            if (FileDlg::open (hwnd)) {             //若開檔成功
               if (player.bPlaying) {             //關閉計時器
                     player.free();
                     KillTimer (hwnd, ID_TIMER);
               }
               bPause = false;
               swprintf_s (e_str, L"%s", FileDlg::fname);
               SetWindowText (hwnd, e_str);
               player.init();
               player.run (FileDlg::fname, hwnd);
               SetTimer (hwnd, ID_TIMER, 20, 0);    //啟動計時器
            }
         }else if (ID_PAUSE == LOWORD(wParam))
            player.pause (bPause = !bPause);
         return 0;

   default: return  DefWindowProc (hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain (HINSTANCE hInst, HINSTANCE, PSTR, int nShow)
{
CoInitialize (0);
WNDCLASSEX wc = {0x30,3,WndProc,0,0,hInst,0,0,(HBRUSH)1,0,L"DS",0};
if (!RegisterClassEx(&wc)) return 0;
HWND hwnd = CreateWindow (L"DS",L"Player",
      13565952,100,50,560,500,0,0,hInst,0);
if (!hwnd) return 0;
e_hInst = hInst;
MSG msg; ShowWindow (hwnd, nShow);
while (GetMessage (&msg, 0,0,0)) {
      TranslateMessage (&msg);
      DispatchMessage (&msg);
}
CoUninitialize();
return msg.wParam;
}

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