C Programming Starter Kit 2.0/SamsPublishing-CProgrammingStarterKit-v2.0-Win31.iso/tybc4/14_5.cpp

C/C++ Source or Header | 1994-05-26 | 6KB | 197 lines

     #include <owl\framewin.h>
     #include <owl\applicat.h>
     #include <owl\dc.h>
     #include <mem.h>

     #pragma hdrstop

     #include "real.rh"

     const int maxLines = 25;
     const int maxWidth = 80;
     const int maxData = maxLines * (maxWidth + 1);

     class BaseWindow : public TWindow
       {
     protected:
       int   currentLine;         // line being typed in now
       int   lineLen[maxLines];   // length of each line
       char *linePtrs[maxLines];  // string for each line
       BOOL  isMinimized;         // TRUE if window is an icon
       TSize windowSize;          // structure with size in pixels

       void EvChar(UINT key, UINT repeatCount, UINT flags);
       void Paint(TDC& dc, BOOL, TRect&);
       void EvSize(UINT sizeType, TSize& size);

       void CmAbout();
       void CmClear();

       // Menu choice, end the program
       void CmFileExit() { PostQuitMessage(0); }

     public:
       BaseWindow(TWindow *parent = 0);
       ~BaseWindow() {}
       DECLARE_RESPONSE_TABLE(BaseWindow); // says we'll have a
       };                                  // response table

     DEFINE_RESPONSE_TABLE1(BaseWindow, TWindow)
       EV_WM_CHAR,
       EV_WM_SIZE,
       EV_COMMAND( CM_ABOUT,    CmAbout),
       EV_COMMAND( CM_FILEEXIT, CmFileExit),
       EV_COMMAND( CM_CLEAR,    CmClear),
     END_RESPONSE_TABLE;

     class MyApp : public TApplication
       {
     public:
       MyApp() : TApplication() {}

       void InitMainWindow();
       };

     BaseWindow::BaseWindow(TWindow *parent)
       {
       int lineNum;

       Init(parent, 0, 0);
       linePtrs[0] = new char[maxData]; // allocate edit buffer
       lineLen[0] = currentLine = 0;

       // apportion the buffer out to the line pointer array
       for (lineNum = 1; lineNum < maxLines; ++lineNum)
         {
         linePtrs[lineNum] = linePtrs[lineNum - 1] + maxWidth;
         lineLen[lineNum] = 0;
         }
       }

     // Menu choice, display an About box,
     // use a message box to do it
     void
       BaseWindow::CmAbout()
       {
       MessageBox("Teach Yourself BC++ 4 in 21 Days", "About");
       }

     // Menu choice, clear the display
     void
       BaseWindow::CmClear()
       {
       for (int lineNum = 0; lineNum < maxLines; ++lineNum)
         lineLen[lineNum] = 0;    // empty all lines

       currentLine = 0;           // move back to top line
       Invalidate();              // window is invalid, repaint
       }

     // this is called whenever the window changes size
     void
       BaseWindow::EvSize(UINT sizeType, TSize& size)
       {
       if (sizeType == SIZE_MINIMIZED) // if shrunk to icon
         isMinimized = TRUE;
       else
         {
         windowSize = size;            // save window size
         isMinimized = FALSE;
         }
       }

     // called when time to update (paint) the screen
     void
       BaseWindow::Paint(TDC& dc, BOOL, TRect&)
       {
       int   lineNum;         // line number to write
       int   yPos;            // vertical position on screen
       int   displayedLines;  // number of linePtrs in this window
       TSize textSize;        // used to get char height in pixels

       if (isMinimized)       // don't write to an icon
          return;

       // get char sizes so that height is saved
       textSize = dc.GetTextExtent("W", 1);
       displayedLines = windowSize.cy / textSize.cy;

       if (displayedLines > maxLines)
          displayedLines = maxLines;

       for (lineNum = yPos = 0; lineNum < displayedLines; ++lineNum)
          {
          if (lineLen[lineNum] > 0)  // if any text on the line
             dc.TextOut(0, yPos, linePtrs[lineNum], lineLen[lineNum]);

          yPos += textSize.cy;   // adjust screen line position
          }
       }

     // called when a normal key is pressed
     void
       BaseWindow::EvChar(UINT key, UINT repeatCount, UINT)
       {
       BOOL invalidDisplay = FALSE;
       BOOL eraseBackground = FALSE;

       while (repeatCount--)
         {
         if ((key >= ' ') && (key <= '~')) // if a printable key
           {
           if (currentLine >= maxLines) // if buffer full
             {
             MessageBeep(-1);           //   complain
             break;
             }
           else                         // else
             {                          //   add char
             linePtrs[currentLine][lineLen[currentLine]] = (char) key;

             if (++lineLen[currentLine] >= maxWidth)
               ++currentLine;

             invalidDisplay = TRUE;
             }
           }
         else if (key == '\b')  // rubout, delete char
           {
           if (currentLine >= maxLines)
             break;
           else if (lineLen[currentLine] == 0)
             {
             if (currentLine > 0)
               --currentLine;
             }
           else
             --lineLen[currentLine];

           invalidDisplay = eraseBackground = TRUE;
           }
         else if (key == '\r') // if carriage return (Enter key)
            ++currentLine;
         }

       if (currentLine >= maxLines)
         currentLine = maxLines - 1;

       if (invalidDisplay)            // if buffer has changed
         Invalidate(eraseBackground); //   force window repaint
       }

     void
       MyApp::InitMainWindow()
       {
       SetMainWindow(new TFrameWindow(0, "Program 14.5",
                                      new BaseWindow()));
       GetMainWindow()->AssignMenu("MENU_1");
       }

     int
       OwlMain(int, char **)
       {
       return MyApp().Run();
       }