Source code for Windows Progress Bar Control and test program;
documentation at http://www.alumni.caltech.edu/~pje/progress.html

Philip J. Erdelsky

=============================== PROGRESS.CPP ===============================

// Windows Progress Bar Control

#include <windows.h>
#include "progress.h"

LRESULT CALLBACK ProgressBarProc(HWND, UINT, WPARAM, LPARAM);

/*-----------------------------------------------------------------------------
This function registers the PROGRESSBAR class. It is called automatically when
the program starts up.

The external variables _hPrev and _hInstance duplicate the arguments
hPrevInstance and hInstance, which are passed to WinMain(). If the startup
code does not supply these external variables, you must pass the arguments to
this function and call it explicitly before invoking any PROGRESSBAR control.
-----------------------------------------------------------------------------*/

extern HINSTANCE _hInstance;

#ifndef WIN32
  extern HINSTANCE _hPrev;
#endif

static void register_progress_bar(void)
{
  #ifndef WIN32
    if (!_hPrev)
  #endif
  {
    WNDCLASS w;
    w.cbClsExtra = 0;
    w.cbWndExtra = 4*sizeof(WORD);
    #ifdef WIN32
      w.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1);
    #else
      w.hbrBackground = (HBRUSH) COLOR_WINDOW + 1;
    #endif
    w.hCursor = LoadCursor(NULL, IDC_ARROW);
    w.hIcon = NULL;
    w.hInstance = _hInstance;
    w.lpfnWndProc = ProgressBarProc;
    w.lpszClassName = "PROGRESSBAR";
    w.lpszMenuName = NULL;
    w.style = 0;
    RegisterClass(&w);
  }
}

#pragma startup register_progress_bar

#ifdef WIN32

  inline void MoveTo(HDC dc, int x, int y)
  {
    MoveToEx(dc, x, y, NULL);
  }

  #define GetWindowHandle GetWindowLong
  #define SetWindowHandle SetWindowLong
  #define GWH_HINSTANCE GWL_HINSTANCE
  #define HANDLE_WORD DWORD

  inline void PostClickedMessage(HWND handle)
  {
    PostMessage(GetParent(handle), WM_COMMAND,
    MAKELONG((WORD) GetMenu(handle), BN_CLICKED), (LPARAM) handle);
  }

#else

  #define GetWindowHandle GetWindowWord
  #define SetWindowHandle SetWindowWord
  #define GWH_HINSTANCE GWW_HINSTANCE
  #define HANDLE_WORD WORD

  inline void PostClickedMessage(HWND handle)
  {
    PostMessage(GetParent(handle), WM_COMMAND,
      GetMenu(handle), MAKELONG(handle, BN_CLICKED));
  }

#endif

/*-----------------------------------------------------------------------------
This function receives all messages directed to the control.
-----------------------------------------------------------------------------*/

long far pascal _export ProgressBarProc(HWND handle, UINT message,
  WPARAM wParam, LPARAM lParam)
{
  WORD height = GetWindowWord(handle, 0);
  WORD width = GetWindowWord(handle, 2);
  WORD completed = GetWindowWord(handle, 4);
  WORD total = GetWindowWord(handle, 6);
  switch (message)
  {
    case WM_CREATE:
    {
      SetWindowWord(handle, 0, ((CREATESTRUCT far *) lParam)->cy);  // height
      SetWindowWord(handle, 2, ((CREATESTRUCT far *) lParam)->cx);  // width
      SetWindowWord(handle, 6, 100); // default value of total
      return 0;
    }
    case WM_PAINT:
    {
      PAINTSTRUCT paint;
      HDC dc = BeginPaint(handle, &paint);
      HPEN pen = CreatePen(PS_SOLID, 1, GetSysColor(COLOR_WINDOWTEXT));
      HPEN old_pen = SelectObject(dc, pen);
      HBRUSH brush = CreateSolidBrush(GetSysColor(COLOR_WINDOW));
      HBRUSH old_brush = SelectObject(dc, brush);
      RECT r;
      char text[5];
      // draw border
      Rectangle(dc, 0, 0, width-1, height-1);
      // display completion percentage
      SetTextColor(dc, GetSysColor(COLOR_WINDOWTEXT));
      SetBkColor(dc, GetSysColor(COLOR_WINDOW));
      r.left = r.top = 1;
      r.bottom = height - 2;
      r.right = width - 2;
      wsprintf(text, "%d%%", (100L * (DWORD) completed) / (DWORD) total);
      DrawText(dc, text, lstrlen(text), &r, DT_CENTER | DT_VCENTER | DT_SINGLELINE);
      // invert progress portion
      r.right = 1 + ((DWORD) (width - 3) * (DWORD) completed) / (DWORD) total;
      if (r.right > r.left)
        InvertRect(dc, &r);
      SelectObject(dc, old_pen);
      DeleteObject(pen);
      SelectObject(dc, old_brush);
      DeleteObject(brush);
      EndPaint(handle, &paint);
      return 0;
    }
    case PB_SETCOMPLETED:
    {
      RECT r;
      r.top = 1;
      r.bottom = height - 2;
      SetWindowWord(handle, 4, wParam); // completed
      if ((100L * (DWORD) wParam) / (DWORD) total != (100L * (DWORD) completed) / (DWORD) total)
      {
        HDC dc = GetDC(handle);
        #ifdef WIN32
          SIZE size;
          GetTextExtentPoint32(dc, "100%", 4, &size);
          unsigned text_width = size.cx;
        #else
          unsigned text_width = (WORD) GetTextExtent(dc, "100%", 4);
        #endif
        r.left = 1 + (width - 2) / 2 - (text_width + 1) / 2;
        r.right = 1 + (width - 2) / 2 + (text_width + 1) / 2;
        InvalidateRect(handle, &r, TRUE);
        ReleaseDC(handle, dc);
      }
      r.left = 1 + ((DWORD) (width - 3) * (DWORD) completed) / (DWORD) total;
      r.right = 1 + ((DWORD) (width - 3) * (DWORD) wParam) / (DWORD) total;
      if (r.left != r.right)
      {
        if (r.left > r.right)
        {
          int x = r.left;
          r.left = r.right;
          r.right = x;
        }
        InvalidateRect(handle, &r, TRUE);
      }
      return 0;
    }
    case PB_GETCOMPLETED:
      return completed;
    case PB_SETTOTAL:
      SetWindowWord(handle, 6, wParam); // total
      SetWindowWord(handle, 4, 0); // completed
      InvalidateRect(handle, NULL, TRUE);
      return 0;
    case PB_GETTOTAL:
      return total;
  }
  return DefWindowProc(handle, message, wParam, lParam);
}


=============================== PROGRESS.H   ===============================

#define  PB_GETCOMPLETED     (WM_USER+0)
#define  PB_SETCOMPLETED     (WM_USER+1)
#define  PB_GETTOTAL         (WM_USER+2)
#define  PB_SETTOTAL         (WM_USER+3)


=============================== PROGTEST.CPP ===============================

// Windows Progress Bar Control Test Program

#include <windows.h>
#include "progress.h"
#include "progtest.h"

extern "C" {
  long far pascal _export WndProc(HWND, UINT, WORD, LONG);
  int pascal WinMain(HINSTANCE, HINSTANCE, LPSTR, int);
}

const TOTAL = 500;

long far pascal _export WndProc(HWND hwnd, UINT message, WORD wParam,
  LONG lParam)
{
  switch (message)
  {
    case WM_CREATE:
      return 0;
    case WM_COMMAND:
      switch (wParam)
      {
        case LOWER:
        {
          int n =
            SendDlgItemMessage(hwnd, PROGRESSBAR, PB_GETCOMPLETED, 0, 0L);
          n = n - 1;
          if (n < 0) n = TOTAL;
          SendDlgItemMessage(hwnd, PROGRESSBAR, PB_SETCOMPLETED, n, 0L);
          return 0;
        }
        case HIGHER:
        {
          int n =
            SendDlgItemMessage(hwnd, PROGRESSBAR, PB_GETCOMPLETED, 0, 0L);
          n = n + 1;
          if (n > TOTAL) n = 0;
          SendDlgItemMessage(hwnd, PROGRESSBAR, PB_SETCOMPLETED, n, 0L);
          return 0;
        }
      }
      break;
    case WM_CLOSE:
      DestroyWindow(hwnd);
      return 0;
    case WM_DESTROY:
      PostQuitMessage(0);
      return 0;
  }
  return DefDlgProc (hwnd, message, wParam, lParam);
}

#pragma argsused
int pascal WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    LPSTR lpszCmdLine, int nCmdShow)
{
    HWND hwnd;
    MSG msg;

    if (!hPrevInstance)
    {
      WNDCLASS wndclass;
      wndclass.style = 0;
      wndclass.lpfnWndProc = (WNDPROC) WndProc;
      wndclass.cbClsExtra = 0;
      wndclass.cbWndExtra = DLGWINDOWEXTRA;
      wndclass.hInstance = hInstance;
      wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
      wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
      wndclass.hbrBackground = NULL;
      wndclass.lpszMenuName = NULL;
      wndclass.lpszClassName = "PROGRESSTEST";
      RegisterClass (&wndclass);
    }

    hwnd = CreateDialog(hInstance, "PROGRESSTEST", 0, NULL);
    SendDlgItemMessage(hwnd, PROGRESSBAR, PB_SETTOTAL, TOTAL, 0L);

    ShowWindow(hwnd, nCmdShow == SW_SHOWMAXIMIZED ? SW_SHOW : nCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
      if (!IsDialogMessage (hwnd, &msg))
          DispatchMessage (&msg);

    return msg.wParam;
}


=============================== PROGTEST.H   ===============================

#define  PROGRESSBAR   101
#define  LOWER         102
#define  HIGHER        103


=============================== PROGTEST.RC  ===============================

#include "progtest.h"

PROGRESSTEST DIALOG 6, 15, 161, 127
STYLE WS_POPUP | WS_VISIBLE | WS_CAPTION | WS_SYSMENU
CLASS "PROGRESSTEST"
CAPTION "Progress Bar Test"
FONT 8, "MS Sans Serif"
{
 PUSHBUTTON "lower", LOWER, 12, 84, 50, 14
 CONTROL "", PROGRESSBAR, "PROGRESSBAR", 0 | WS_CHILD | WS_VISIBLE, 9, 18, 144, 14
 PUSHBUTTON "higher", HIGHER, 96, 84, 50, 14
}