How To Accurately Showing on the Screen What Will Print (75469)


The information in this article applies to:

  • Microsoft Windows Software Development Kit (SDK) 3.1
  • Microsoft Win32 Application Programming Interface (API), when used with:
    • Microsoft Windows NT Server 3.5
    • Microsoft Windows NT Server 3.51
    • Microsoft Windows NT Workstation 3.5
    • Microsoft Windows NT Workstation 3.51
This article was previously published under Q75469

SUMMARY

Many applications have an option where the screen display is set to closely correspond to the printed output. This article discusses some of the issues involved in implementing this feature.

MORE INFORMATION

If a screen font is available that exactly matches (or at least very closely corresponds to) the chosen printer font, then the process is very straightforward and consists of seven steps:
  1. Retrieve a Device Context (DC) or an Information Context (IC) for the printer.
  2. Call EnumFontFamilies() to obtain a LOGFONT structure for the selected printer font. The nFontType parameter to the EnumFontFamilies() callback function specifies if a given font is a device font.
  3. Get a DC for the screen.
  4. Convert the lfHeight and lfWidth members of the LOGFONT structure from printer resolution units to screen resolution units. If a mapping mode other than MM_TEXT is used, round-off error may occur.
  5. Call CreateFontIndirect() with the LOGFONT structure.
  6. Call SelectObject(). GDI will select the appropriate screen font to match the printer font.
  7. Release the printer device context or information context and the screen device context.
If a screen font that corresponds to the selected printer font is not available, the process is more difficult. It is possible to modify the character placement on the screen to match the printer font to show justification, line breaks, and page layout. However, visual similarity between the printer fonts and screen fonts depends on a number of factors, including the number and variety of screen fonts available, the selected printer font, and how the printer driver describes the font. For example, if the printer has a serifed Roman- style font, one of the GDI serifed Roman-style fonts will appear to be very similar to the printer font. However, if the printer has a decorative Old English-style font, no corresponding screen font will typically be available. The closest available match would not be very similar.

To have a screen font that matches the character placement of a printer font, do the following:
  1. Perform the preceding seven steps to retrieve an appropriate screen font.
  2. Get the character width from the TEXTMETRIC structure returned by the EnumFonts function in step 2 above. Use this information to calculate the page position of each character to be printed in the printer font.
  3. Allocate a block of memory and specify the spacing between characters. Make sure that this information is in screen resolution units.
  4. Specify the address of the memory block as the lpDx parameter to ExtTextOut(). GDI will space the characters as listed in the array.
Modification Type:MinorLast Reviewed:2/11/2005
Keywords:kbhowto KB75469
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