Metric Information Contained in Fonts

This section gives an explanation of how to set the fields of the FOCAMETRICS structure when developing:

• A bit map or outline font for general use by PM graphics applications

• A description of a bit map or outline device font that is built in to a device or can be downloaded to a device.

The following structure contains the physical font metrics used when creating fonts. It is defined in the file \INCLUDE\PMFONT.H.

typedef struct _FOCAMETRICS {        ULONG   ulIdentity;
        ULONG   ulSize;
        CHAR    szFamilyname[32];
        CHAR    szFacename[32];
        SHORT   usRegistryId;
        SHORT   usCodePage;
        SHORT   yEmHeight;
        SHORT   yXHeight;
        SHORT   yMaxAscender;
        SHORT   yMaxDescender;
        SHORT   yLowerCaseAscent;
        SHORT   yLowerCaseDescent;
        SHORT   yInternalLeading;
        SHORT   yExternalLeading;
        SHORT   xAveCharWidth;
        SHORT   xMaxCharInc;
        SHORT   xEmInc;
        SHORT   yMaxBaselineExt;
        SHORT   sCharSlope;
        SHORT   sInlineDir;
        SHORT   sCharRot;
        USHORT  usWeightClass;
        USHORT  usWidthClass;
        SHORT   xDeviceRes;
        SHORT   yDeviceRes;
        SHORT   usFirstChar;
        SHORT   usLastChar;
        SHORT   usDefaultChar;
        SHORT   usBreakChar;
        SHORT   usNominalPointSize;
        SHORT   usMinimumPointSize;
        SHORT   usMaximumPointSize;
        SHORT   fsTypeFlags;
        SHORT   fsDefn;
        SHORT   fsSelectionFlags;
        SHORT   fsCapabilities;
        SHORT   ySubscriptXSize;
        SHORT   ySubscriptYSize;
        SHORT   ySubscriptXOffset;
        SHORT   ySubscriptYOffset;
        SHORT   ySuperscriptXSize;
        SHORT   ySuperscriptYSize;
        SHORT   ySuperscriptXOffset;
        SHORT   ySuperscriptYOffset;
        SHORT   yUnderscoreSize;
        SHORT   yUnderscorePosition;
        SHORT   yStrikeoutSize;
        SHORT   yStrikeoutPosition;
        SHORT   usKerningPairs;
        SHORT   sFamilyClass;
        PSZ     pszDeviceNameOffset;
} FOCAMETRICS;

Note: FOCAMETRICS is a parallel structure with FONTMETRICS as returned to applications in the GpiQueryFonts and GpiQueryFontMetrics function calls.

The FONTMETRICS fields are derived from FOCAMETRICS by the Presentation Manager graphics engine. Most values are passed though unchanged. The exceptions are:

• The Identity field. This must be 1. This field is not a part of the FONTMETRICS structure.

• The Size field. This must be set to the size of the FOCAMETRICS structure. This field is not a part of the FONTMETRICS structure.

• The Codepage field. Ignore the description in FONTMETRICS, and use the following:

  Place 850 in this field if the font is intended to support any PM supported code page.

  Place 65400 in this field if the font has special glyphs, for example if it is a Symbol font.

  Place other valid code pages in this field if the font is specific to this code page.

  Do not place other values in this field.

  
  FONTMETRICS fields which contain values in world coordinates. The corresponding field in FOCAMETRICS should contain pel values for bit-map fonts, and notional units for outline fonts.

  See FONTMETRICS for a detailed explanation of the fields.

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