Visual Properties

When looking to format a run of text the first property that one might need to specify would be the font typeface. The XML file format allows for the specification of not only Latin Fonts but also East Asian, Complex Script, and Symbol fonts as well. These four font buckets give the application additional information that is used to layout text in a manner fitting for the specific font. Along with the actual font being used, comes the size of the font. To specify this simply use the @sz attribute and along with a value that is 1/100th of the size in points.

Other common formatting properties allowed in the XML framework are bold, italic, underline and strikethrough. The use of both the bold and italic properties is simply via a Boolean value of 0 or 1. The usage of the underline and strikethrough, however, allow a more specific selection to be made. There are 17 values for underline, which range from a single line to wavy double lines. In addition to specifying the style of underline that is to be used, the framework can also specify fill properties for the underline. These are solid color, multi-color gradient, and texture fill. For strikethrough, there are two options: single and double strike through.

When standard formatting isn't adequate, more complex effects can be defined for a specific run of text. The basic breakdown for these is line properties, fill properties and effect properties. Encapsulated within each of these areas is a wide range of customizable effects. A quick look at line properties, for example, reveals the ability to specify a color, gradient, or pattern fill, along with a width and style applied. Along these lines fill properties allows for transparent fill, solid fill, gradient fill, texture fill and even picture fill. While these features alone give the XML file format plenty of robustness in describing text, other features are also available. Because text is treated the same as a shape, a run of text can have virtually all shape effects applied to it just as if it were a shape. These effects include shadow, glow, and reflection, and are placed in an effect list under the run properties tag. An example of what these lines, fills and effects may look like is provided below. More information on these effects can be found in either dml-shapeLineProperties.xsd or dml-shapeEffects.xsd.

<a:rPr>
  <a:ln>
    <a:solidFill … />     Line properties here
  </a:ln>
  <a:gradFill>
    <a:gsLst … />         Fill properties here
  </a:gradFill>
  <a:effectLst> 
    <a:reflection … />    Effect properties here
  </a:effectLst>
</a:rPr>

A few additional properties are worth noting:

  • Minimum kerning size: This specifies the smallest font size at which kerning still occurs. When no tag is present for this the default value is 0, allowing kerning at any text size.

  • Spacing between characters: The units here are the same as are used for font size. Along the lines of specifying horizontal spacing, vertical spacing can be specified via the baseline tag. This is typically used for subscript and superscript text and is specified in the same units as font size.

  • Capitalization and Normalize: Capitalization sets the case of the character to either all small caps or all large caps. For this property there are only these two settings aside from the "none" setting at which point this property is ignored. Normalize height takes all shorter characters and adjusts their height up so that they are the same as taller characters. This property is set via a Boolean value.