a:alphaOff (Alpha Offset)

Alpha offset adjustment for a color.

Parent elements

Child elements

(none)

Description

a:alphaOff is a DrawingML element used to describe part of a shape, chart, image, or text run. It is defined in ECMA-376 Part 1.

This article documents the a:alphaOff element from the DrawingML schema (ECMA-376 Part 1). The element is used to apply an offset to the alpha channel of a color value (for example to slightly lighten or darken a color’s transparency).

Attributes

Attribute	Type	Possible Values	Description
`val`	ST_FixedPercentage	0..100000	Offset value applied to the alpha channel (in DrawingML fixed-percentage units).

Examples

<alphaOff>
  <!-- Example DrawingML content -->
</alphaOff>

using System.Xml.Linq;

var ns = "http://schemas.openxmlformats.org/drawingml/2006/main";
var solidFill = new XElement(XName.Get("solidFill", ns),
  new XElement(XName.Get("srgbClr", ns),
    new XAttribute("val", "FF0000"),
    new XElement(XName.Get("alphaOff", ns), new XAttribute("val", "25000"))
  )
);

// Serialize or insert `solidFill` into the drawing XML where a fill is expected.
// For Open XML SDK usage, the same structure is represented by the
// `SolidFill` / `RgbColorModelHex` elements and a child alpha element.

Notes

DrawingML elements are commonly used inside shape properties, text bodies, charts, and image fills.
The exact allowed content model depends on the surrounding OOXML part and the schema version in use.