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GetTextExtentPoint32 fails on Printer...

Posted on 1997-05-07
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Last Modified: 2013-12-04
If I call hdc = CreateCompatibleDC(hPrinterDC), assuming the printerDC is valid, and then call GetTextExtentPoint(hdc,...), this call crashes the computer everytime. GetTextExtentPoint32 also crashes, but I need to know the size (height and width) of a string for size it will be on the printer. This code works fine for the screen when I am not printing.

What am I doing wrong?

Jordan Pinsker
pinskerj@vu.union.edu
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Question by:jordanp
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NickRepin earned 100 total points
Comment Utility
CreateCompatibleDC() can only be used with devices that support raster operations. You can determine whether a printer supports these operations by calling the GetDeviceCaps(hPrinterDC,RASTERCAPS) function. Do you check hdc!=NULL?Also, why do not to use GetTextExtentPoint32(hPrinterDC)?See also MS knowledge base article Q22553.
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by:jordanp
Comment Utility
Your proposed answer helped a little but did not solve my overall problem. Maybe this will explain things better.

I am creating a bitmap based on the PrinterDC. I draw text to this bitmap to rotate it, and then draw the bitmap to a certain portion of the printed page. Thus, for this to work just as it does for my print preview, I need to create a comaptibleDC for the printer.

I used your suggestion and only changed the GetTextExtentPoint32 to use hPrinterDC, and created the bitmap by calling createcompatiblebitmap(hPrinterDC), but for whatever reason the text is becoming corrupted when printing (it appears that the bitmap is too large and it is printing garbage after the text). I am not sure if this is caused by the differences between the printer and the page as it works fine on screen. Here is my function below:

HANDLE GetRotateText (char * TextName, HWND TitleText, BOOL      left)
     {
     static LOGFONT lf ;
     HBITMAP        hBitmap ;
     HDC            hdc, hdcMem ;
     HFONT          hFont ;
     SIZE           size ;
     CHARFORMAT         CF;
        BITMAPINFOHEADER      bi;
      
       if (gPrinter == true) // we are using the printer, not screen
               SetMapMode(hPrinterDC,MM_TEXT);
      
     CF.cbSize = sizeof(CF);
        SendMessage (TitleText,EM_GETCHARFORMAT, 1, (LPARAM)&CF);

     hdc = CreateIC ("DISPLAY", nil, nil, nil);
     hdcMem = CreateCompatibleDC (hdc);
     
     lf.lfUnderline = (CF.dwEffects & CFE_UNDERLINE);
     lf.lfStrikeOut =  (CF.dwEffects & CFE_STRIKEOUT);
     if (CF.dwEffects & CFE_BOLD)
       lf.lfWeight = 700;
     else
       lf.lfWeight = 400;
       lf.lfItalic = (CF.dwEffects & CFE_ITALIC);

            // Get the size of the text...
       if (false == gPrinter)
             lf.lfHeight = -MulDiv(CF.yHeight/20, GetDeviceCaps(hdcMem,
LOGPIXELSY), 72);
       else
             lf.lfHeight = -MulDiv(CF.yHeight/20, GetDeviceCaps(hPrinterDC,
LOGPIXELSY), 72);

     lstrcpy ((char *) lf.lfFaceName, CF.szFaceName) ;
         
 hFont = (HFONT) SelectObject (hdcMem, CreateFontIndirect (&lf));
     if (false == gPrinter)
           {
                 GetTextExtentPoint32 (hdcMem, TextName, strlen (TextName), &size);
                hBitmap = CreateCompatibleBitmap (hdcMem, size.cy, size.cx) ;//switch x,y for rotation...
            }
     else
           {
                 GetTextExtentPoint32 (hPrinterDC, TextName, strlen (TextName),
&size);
                  hBitmap = CreateCompatibleBitmap (hPrinterDC, size.cy, size.cx) ;//switch x,y for rotation...
            }
         
     if (left)
     lf.lfEscapement = lf.lfOrientation = 900 ;//90 degrees
     else
     lf.lfEscapement = lf.lfOrientation = 2700 ;//270 degrees
   
     SelectObject (hdcMem, hBitmap) ;
       hFont = (HFONT) SelectObject (hdcMem, CreateFontIndirect (&lf));

       if (left)
             TextOut (hdcMem, 0,size.cx, TextName, strlen (TextName));
       else
        TextOut (hdcMem, size.cy,0, TextName, strlen (TextName))      
     
DeleteObject (SelectObject (hdcMem, hFont)) ;
     DeleteDC (hdcMem) ;
     DeleteDC (hdc) ;
      
       if (gPrinter == true) // return to twips for the printer...
               SetMapMode(hPrinterDC,MM_TWIPS);
      
 // Now convert the bitmap to a dib and return it...
       bi.biSize = sizeof(BITMAPINFOHEADER);
       bi.biWidth = size.cy;
     bi.biHeight = size.cx;
     bi.biPlanes = 1;
     bi.biBitCount = 16;
     bi.biCompression = BI_RGB;
     bi.biSizeImage = 0;
     bi.biXPelsPerMeter = 0;
     bi.biYPelsPerMeter = 0;
     bi.biClrUsed = 0;
     bi.biClrImportant = 0;
      
       return (DibFromBitmap (hBitmap,BI_RGB,32,CreateBIPalette (&bi)));

           // must dipose of old bitmap before return hBitmap; not done yet
     }



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Expert Comment

by:NickRepin
Comment Utility
It seems that you use Win95, don't you?
There is no problem to rotate text in WinNT.

As to your code,

1) you should select font on printerDC to call GetTextExtentPoint:

   hFont = (HFONT) SelectObject (hdcMem, CreateFontIndirect (&lf));
   hPrinterDC = (HFONT) SelectObject (hPrinterDC, CreateFontIndirect (&lf));
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   if (false == gPrinter) {
      GetTextExtentPoint32 (hdcMem, TextName, strlen (TextName), &size);
      hBitmap = CreateCompatibleBitmap (hdcMem, size.cy, size.cx) ;//switch x,y for rotation...
   }
   else {
      GetTextExtentPoint32 (hPrinterDC, TextName, strlen (TextName),&size);
      hBitmap = CreateCompatibleBitmap (hPrinterDC, size.cy, size.cx) ;//switch x,y for rotation...
   }

2) in my opinion, you should swap lines with TextOut in following code:

   if (left)
      // 90 degrees, from top to bottom
      TextOut (hdcMem, 0,size.cx, TextName, strlen (TextName));
   else
      // 270 degrees, from bottom to top
      TextOut (hdcMem, size.cy,0, TextName, strlen (TextName));

3) why do not to print directly to hPrinterDC (or to screen) by TextOut  with lf.lfEscapement=lf.lfOrientation != 0 ?

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