Hershey Font wrapper class

• Download demo project - 27.4 KB

• Download FontEdit sample program - 44.6 KB
• Download Font data files - 132.6 KB

Recently when building a GIS display system, I ran into the problem of displaying characters at many different sizes, rotations (escapments), and in several typefaces all in the same view. Unfortunately, the redraw performance I was able to obtain using Windows' font routines was not very good. Reaching back to my past (and definitely showing my age), I decided to use the venerable "Hershey" vector fonts.

All of the font management and display is wrapped up in the class SMFontUtil, the use of which is illustrated in the FontDemo program included. The only method of any real consequence is:

void SMFontUtil::DrawString(
	CDC * pDC,            //device context to draw to
	CPoint pStart,        //starting point
	double pRotation,     //rotation angle clockwise in radians (0 = 12:00)
	double pCharWidth,    //width of each character
	double pCharHeight,   //height of each character
	FONT_TYPE pFontType,  //the font to use
	CString pString)      //the string

NOTE: For this article, I hard-coded the path so that the font definition data (found in FontData.zip) must reside in C:\HersheyFonts. In the real system, this is stored on a server with the GIS data.

The original Hershey font character codes do not match well ASCII. I have built a translation table that maps ASCII character and font to a Hershey character. The included fonts are:

• SMALL_SIMPLEX
• SMALL_DUPLEX
• SIMPLEX
• DUPLEX
• TRIPLEX
• MODERN
• SCRIPT_SIMPLEX
• SCRIPT_DUPLEX
• ITALLIC_DUPLEX
• ITALLIC_TRIPLEX
• FANCY
• GOTHIC

I have also included a crude font editor that lets you edit the vertices and the translation table. To edit a character, right click on it in any view. To assign a hershey font to a ASCII font family pairing select the character in the numeric view and select "index save" from the menu. Switch to Xlated view and select the target cell, then select "Assign Index".

The font data resides in two files. The vector data, and the translation table I have supplied both the runtime version, and a human readable version in CSV format for those who wish to use them. The SMFontUtils class provides a method to convert from the CSV to the runtime. Again, please note that for the purposes of this article, the font definition data (FontData.zip) must be extracted into C:\HersheyFonts.

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