a:alphaModClr (Alpha Modified Color)

Description

a:alphaModClr is the DrawingML alpha-modified color element that applies alpha (transparency) modifications to a base color. It is defined in ECMA-376 Part 1 §20.1.2.3.10.

Alpha modifications allow you to:

• Apply transparency adjustments to colors without changing the hue
• Create semi-transparent versions of scheme colors
• Adjust opacity for hover states and effects
• Maintain color consistency while varying transparency

Common uses:

• Hover states with reduced opacity
• Shadow and effect colors with transparency
• Disabled state colors with reduced visibility

Attributes

Examples

Scheme Color with 50% Opacity

<a:alphaModClr>
  <a:alphaOff val="-50000"/>
</a:alphaModClr>

using DocumentFormat.OpenXml.Drawing;

var alphaModClr = new AlphaModulateColor();
var alphaOff = new AlphaOffset { Val = -50000 }; // 50% transparency
alphaModClr.Append(alphaOff);

Fully Transparent Color

<a:alphaModClr>
  <a:alphaMod val="0"/>
</a:alphaModClr>

var alphaModClr = new AlphaModulateColor();
var alphaMod = new AlphaModulate { Val = 0 }; // 0% opacity
alphaModClr.Append(alphaMod);

Notes

• Alpha values: -100000 to 100000 (scale from 0% to 100%)
• alphaOff: shifts alpha (val=-50000 = 50% reduction)
• alphaMod: multiplies alpha (val=50000 = 50% of original)
• Typically used with parent color in scheme or system color definitions
• Child modifications stack on parent transparency