Microsoft KB Archive/80900

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Windows 3.1 Application Compatibility (part 5 of 7)

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Q80900

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The information in this article applies to:


 * Microsoft Windows Software Development Kit (SDK) 3.1

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Application Compatibility Document for Windows 3.1
Due to the amount of information in this document, it has been broken into seven pieces. To find all seven pieces of this document and the Windows 3.1 Compatibility Test checklist, query this knowledge base on the words:

"prod(winsdk) and 31compattest"

TrueType
Although Windows version 3.1 includes support that seamlessly integrates TrueType fonts into existing applications, problems with fonts can occur for Windows version 3.0 applications that assume bitmap fonts are always available, that Helv and Tms Rmn are always available, and that font sizes are limited. Be sure to thoroughly check fonts in your application, including files and dialogs. Also, because TrueType provides more fonts at more sizes and in more styles, Windows version 3.1 may consume both printer and global memory faster than Windows version 3.0 did. Check your applications with systems and printers that have limited memory.

HELV AND TMS RMN FONTS
MS Sans Serif replaces Helv, and MS Serif replaces Tms Rmn. To support Windows version 3.0 applications that use the Helv and Tms Rmn fonts, the [FontSubstitutes] section in the WIN.INI file maps Helv to MS Sans Serif and Tms Rmn to MS Serif by default. It also maps Times to Times New Roman and Helvetica to Arial.

Potential Problem
Applications that hard code a search for Helv or Tms Rmn may encounter difficulties after not finding these fonts.

Test
Examine your application code and be sure there are no dependencies on the font names Helv and Tms Rmn.

FONT ENUMERATION
Applications should test to ensure that TrueType fonts are enumerated correctly and that they encounter no unexpected font mapping, such as might occur when a TrueType font substitutes for another font and line spacing changes and/or the position of text in documents is recalculated.

Windows continues to support and is fully backward compatible with ATM, Facelift, and Intellifont for Windows. Applications using these other font technologies should encounter no problems.

TRUETYPE ONLY CHECKED
Windows version 3.0 applications may behave unexpectedly if the user has set the &quot;Show Only TrueType Fonts in Applications&quot; check box using the Control Panel.

Potential Problem
An application may fail to locate any fonts if only TrueType fonts are present.

Test
In the Control Panel, choose Fonts, select TrueType, and enable &quot;Show Only TrueType Fonts in Applications.&quot;


 * Check the font dialog boxes in your application. It should list all the TrueType fonts and should not list non-TrueType fonts.

FONT SIZES
TrueType supports a wide variety of sizes for all TrueType fonts. In Windows version 3.1, an application usually gets the requested size if it requests a very small or very large font.

Potential Problem
An application that checks for the smallest or largest font by setting the nHeight parameter in CreateFont to an extreme value will not get the expected results.

Test
Check fonts in dialog boxes, tool bars, and sample files for your application. Be sure they are all readable.

FONTSUBSTITUTES
The [FontSubstitutes] section may cause the GetTextFace function to return a face name that the EnumFonts function does not enumerate. This is done so that an application that asks for Helv (and expects Helv) gets a font named Helv.

Potential Problem
An application that expects matching face names from the EnumFonts and GetTextFace functions may encounter mismatches.

Test
Check the application code and be sure there are no dependencies on GetTextFace and EnumFonts matching.

Potential Problem
ABC-spaced fonts can lead to misplaced cursors, highlights that do not encompass all the text on a line, &quot;pieces&quot; of characters left behind after screen updates, and unexpected clipping of fonts on printers (when a character goes outside the printable area).

Tests

 * 1) Create a document in your application that contains characters close to the edge of the screen and the printable margins. Scroll the document, checking for characters (or pieces of characters) left behind.
 * 2) Highlight text. Be sure the highlight encompasses all characters and that no part of any character (especially the first and last characters) is left out.
 * 3) Print the document. Be sure that no characters are clipped at the edges of the printable region.

Potential Problem
Be sure to try your application with ATM, Facelift, or Intellifont for Windows fonts installed. Do not install more that one of these font managers at a time. Skip this test if your application does not work with these font managers under Windows version 3.0a.

Tests

 * 1) Create a document under Windows version 3.0a using a type manager (such as ATM), bitmap, and device fonts. Look at the document under Windows version 3.1, and be sure the screen appears the same.
 * 2) Print the document with Windows versions 3.0a and 3.1, and be sure the output is identical.

FONT ENUMERATION
Windows version 3.0 applications sometimes create multiple instances of a single font or font family. In particular, some applications handle fonts that a nonraster printer enumerates as different from fonts enumerated for the display, even if the names are the same. TrueType fonts with the same name are identical regardless of the output device. Some Windows version 3.0 applications assume that scalable fonts cannot be available on nonscaling devices. In such cases, the applications intentionally enumerate a single size for every TrueType font even though other sizes are available. Furthermore, some applications assume that bold, italic, and bold italic are always simulated from regular fonts. This is not true with TrueType fonts.

Potential Problem
An application may create multiple instances of the same font.

Tests

 * 1) If your application assumes that scalable fonts could not print on nonscalable devices, such as a PCL printer, it will have problems enumerating fonts. Check the font dialog boxes and sizes listed for TrueType fonts. Many sizes for each TrueType font should be listed.
 * 2) TrueType fonts are shipped in regular, bold, italic, and bold italic. This can cause problems for applications that assume styles were always simulated. Check the font dialog boxes to be sure that each font is listed only once.
 * 3) TrueType fonts appear for both printer and screen. This causes problems for applications that assume printer and screen fonts are always different. Select a nonraster printer (for example, PCL) and check the font dialog boxes to be sure each font is listed only once.

MIXING DEVICE, BITMAP, AND TRUETYPE FONTS
In Windows version 3.1, some fonts, such as the Symbol font, may be supported by a TrueType font, a GDI bitmap font, and a device-specific font. Applications can get unexpected results when printing waterfalls. For example, a Symbol waterfall to a dot matrix printer intermixes the Symbol bitmap with TrueType Symbol. Because no Symbol font is designed for dot matrix resolution, the results can be spectacularly unattractive.

Potential Problem
Printing may mix device, bitmap, and TrueType fonts causing unacceptable output.

Test
Create a document with a nonscalable printer installed, using a device font and a TrueType font. Both fonts must have the same name. Print.

DESKTOP PUBLISHING AND INTERNATIONAL CHARACTERS
Windows version 3.1 includes 22 new international and desktop publishing characters. Unfortunately, these new characters appear only in TrueType fonts; the bitmap fonts do not have them.

Potential Problem
Changing to a bitmap font causes the new characters to appear as &quot;blots.&quot; Some applications may remap the character code range (128 to 159).

Tests

 * 1) Use a TrueType font to create a document using the desktop publishing and international characters. Be sure the characters appear correctly on the screen.
 * 2) Select a bitmap font, and then change to a TrueType font. Be sure the characters still appear correctly.
 * 3) Print the document. Be sure the printout is correct.
 * 4) Using the Char Map application in the Accessories group of Program Manager, use a TrueType font to copy the desktop publishing characters to the clipboard and paste them into your application. Be sure the characters appear correctly.

NOTE: The desktop publishing characters will not be available to dialog boxes that use bitmap fonts exclusively (such as the Find and Replace dialog boxes).

TEXT ROTATION
Although Windows version 3.0 can rotate vector and device fonts, under certain mapping modes it rotates these fonts differently. For compatibility, Windows version 3.1 also rotates fonts differently. However, an application can override this default behavior and direct Windows version 3.1 to rotate all fonts the same by setting the CLIP_LH_ANGLES bit in the lfClipPrecision member of the LOGFONT structure. When this bit is set, Windows version 3.1 rotates all fonts using the same left-hand rule as Windows version 3.0 uses to rotate device fonts.

OTHER CONSIDERATIONS

 * Some applications do not request point sizes correctly. For bitmap fonts, the results are acceptable because only these fonts have a limited range of sizes available. For TrueType fonts, output can be unacceptable because any size requested is available.
 * Applications sometimes set the tmCharWidth to request specific fonts, but Windows now stretches or compresses a TrueType font to match the requested width. Some applications make assumptions that work for bitmaps in many cases but that lead to squashed or clipped lines with TrueType fonts.
 * Windows version 3.1 adds 13 or more fonts to the default list. Some applications may break when more fonts of more types in more styles are enumerated. They do not have test cases that can account for the additional fonts.

Additional query words: 3.10

Keywords : kb16bitonly

Issue type :

Technology : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310