Configuring MathFlow for XMetaL

The integration of MathFlow with XMetaL is defined in the mathflow.mcr file, which is located in <path-to-xmetal>\Author\Startup. This and the following topics give a brief summary of what these macros do.

These macros operate at the application level. They perform such functions as defining global variables and functions, initializing ActiveX objects and customizing the menus and toolbar.

These macros are invoked when the user performs an action on the document. The document's macros will simply call these macros. This places the MathFlow logic in one place and allows new doctypes to easily include MathFlow functionality.

These macros, which are triggered before a document is saved, remove MathFlow specific attributes from the document. MathFlow uses temporary attributes during the editing sessions. For example, when MathFlow generates an image from the MathML, it places its location in the "altimg" attribute.

These macros, which are triggered after a document is saved, set MathFlow specific attributes from the document.

These macros, which are triggered when a document becomes active or inactive, enable or disable specific MathFlow menu items.

These macros are triggered when the view of a document changes. They determine if the document is a MathML document and if images need to be updated.

These macros, which are triggered when text is dropped onto the document, handle generating images if MathML is part of the dropped text.

These macros are invoked when the user clicks on a MathFlow icon on the toolbar or a menu item in the MathFlow menu.

MathFlow allows users to style characters and expressions by requesting particular font faces, weights and slants. While users can specify any font, weight or slant in the underlying MathML markup, what MathFlow actually renders is limited by the availability of fonts on the system. On Windows systems, MathFlow uses two rendering engines, a Java-based engine for the Editor, and a Win32-based engine for preview images and PDF composition. The font and style behavior of both engines is similar, but there are some differences in details as described below.

There are three cases that must be distinguished to understand how MathFlow selects fonts:

MathFlow enables the use of user-defined custom styles definitions as described in Customizing font styles. Custom styles are represented in the MathML markup by attributes specifying style names. Here we give more details about how the association between the style name and the actual font being used is managed.

All character data in a MathML expression must be contained in a token element (MI, MO, MN, MTEXT, etc.) The font used to render the character data is determined by the values of the "mathvariant", "class", "fontfamily", "fontweight" and "fontslant" attributes. The last three attributes are deprecated by MathML 3.0 and are not generated by MathFlow (though they are still honored by the MathFlow rendering engine.) The values for any of these attributes may either be set explicitly on token elements, or inherited from a parent element, usually an MSTYLE element.

When several of these attributes are used, MathFlow uses the following precedences in determining which of them controls the font:

Both the "mathvariant" and "class" values are interpreted as specifying all three components of the fonts specification -- family, weight and slant. Thus, the "mathvariant" value "bold" actually specifies a serif font face, in bold weight, with normal (upright) slant.

To illustrate the above precedence rules, consider and example. If we define the style "myArial" to have family="Arial", weight="normal" and slant="automatic", then the following will display the x in an Arial, normal, upright font, and the y in serif, bold, upright (since mathvariant="bold" takes precedence over fontstyle="italic"):

<math>
  <mstyle mathvariant="bold" fontstyle="italic">
    <mi class="myArial">x</mi><mo>+</mo><mi>y</mi>
  </mstyle>
</math>

Whereas this will display the x in a serif, bold, upright font, and the y in Arial, normal, italic:

<math>
  <mstyle class="myArial" fontstyle="italic">
    <mi mathvariant="bold" >x</mi><mo>+</mo><mi>y</mi>
  </mstyle>
</math>

MathFlow stores the custom font styles you have defined in a file, so that it can be reused from session to session. This file can also be edited directly as a more convenient way of defining a large number of styles, to be shared among many users.

The file in question is named .mfstyles and is stored in the same directory as your MathFlow preferences file, usually the following on Windows systems: C:\Users\<username>.

The font style definition file has an XML syntax with seven elements:

<styles>

The root element that can contain any number of <style> elements.

<style>

Each <style> element must contain one <label> element and one <fontspec> element. It is an error if either of these is missing or appears more than once.

<label>

The name of the style.

If the inner text of this element matches the value of the class attribute in a MathML element, then that MathML element will be stylized according to the <fontspec> element that is a sibling of this <label>.

<fontspec>

This can contain 0-3 of the following three elements which describe the font characteristics of the style. If any of these elements are omitted, the corresponding font characteristic adopts a default value listed below.

For example, the following code defines two font styles named my Arial, my Arial2, and myEmphasis:

<styles>
  <style>
    <label>myArial</label>
    <fontspec>
      <fontfamily>Arial</fontfamily>
      <fontweight>normal</fontweight>
      <fontslant>automatic</fontslant>
    </fontspec>
  </style>
  <style>
    <label>myArial2</label>
    <fontspec>
      <fontfamily>Arial</fontfamily>
      <fontweight>bold</fontweight>
      <fontslant>normal</fontslant>
    </fontspec>
  </style>
  <style>
    <label>myEmphasis</label>
    <fontspec>
      <fontfamily>inherited</fontfamily>
      <fontweight>bold</fontweight>
      <fontslant>italic</fontslant>
    </fontspec>
  </style>
</styles>

In this example, you need all of the characters that are alpha-numeric to use the system font "Arial." To do this, you will need to change the ALPHA_NUMERIC value (ID is 100 in the FontMapping.opt file) to Arial, rather than Times New Roman as shown above. To accomplish this, use the following FontMapping.opt file:

100=Arial
101=Euclid Symbol
102=Code2000
103=Euclid Symbol

This mapping will cause every character MathFlow identifies as an "alpha numeric" character to be displayed in the specified font. Be aware that if you use the wrong font name in FontMapping.opt, you will not see the correct font. It will use MathFlow internal font if it can't find the system font listed in the file. It is possible to pick any system font, but be aware that most system fonts do not contain glyphs for non-alphanumeric characters. Euclid Symbol is a high quality font for common symbol characters, and you will generally not need to change it. However, Code 2000 is a lower-quality, shareware font whose main appeal is that it has exceptionally comprehensive coverage of Unicode, and depending on what symbols you need, you may wish to replace it with a higher quality font. The "GREEK" font defaults to Euclid symbol, since it has high-quality Greek characters, but high-quality fonts with Greek characters in other styles are not uncommon. In general, you may need to experiment to make sure that the system fonts that you pick contain the proper glyph for the Unicode characters you plan to use.

The properties (e.g., spacing) may be different according to the position of the operator in the formula; whether it is in the middle (infix), at the beginning (prefix), or the end (postfix) of an expression. To reflect this, mfopdict.txt should have three tables, each one started by a line with its name: INFIX, PREFIX, or POSTFIX. It is also possible to change the default spacing for all operators (only the spacing, not other properties), by writing a line with an operator name of "default". Values that are not explicitly set for an operator, or not in a "default" line for spacing use MathFlow's internal values.

In brief:

////////////////////////////////////////////////
INFIX
////////////////////////////////////////////////
default, 17, 17
minus, 33, 33
plus, 33, 33
sum, 33, 33, moveablelimits=false
////////////////////////////////////////////////
PREFIX
////////////////////////////////////////////////
default, 17, 17
plus, 3em, 5
sum, 33, 33, moveablelimits=false
////////////////////////////////////////////////
POSTFIX
////////////////////////////////////////////////
plus, 5u, 3em
sum, 33, 33, moveablelimits=true