Chroma Transform

Selectively renders a specified color as transparent for the specified image.

Note To use this transform, you need to have Microsoft® Internet Explorer 5, the Microsoft Windows® 98 OEM Service Release (OSR), or Windows 2000 installed.

Transform Specifications

The following table contains the information you need to use this transform in script.

Globally unique identifier (GUID)	1D4637E3-383C-11D2-952A-00C04FA34F05
Programmatic identifier (ProgId)	DXImageTransform.Microsoft.Chroma
Inputs	One input image is required.
Transform type	Filter

Transform Properties

The following table lists the transform properties that control the appearance of the output.

Property name	Default	Description
Color	0xFF0000FF	The hexadecimal value of the color to be treated as transparent. This color can be expressed in 0xAARRGGBB number format, where AA is the alpha hexadecimal value, RR is the red hexadecimal value, GG is the green hexadecimal value, and BB is the blue hexadecimal value. This value can also be a string which uses the standard HTML color formats "#RRGGBB" or "#AARRGGBB".

Remarks

This effect is not recommended for files that have been dithered from 24-bit to 8-bit color. In particular, JPEG files, which are are both dithered and compressed, do not produce entirely solid transparent regions. The Chroma transform also is not recommended for anti-aliased sources, in which jagged lines are smoothed by blending the lines with the colors of the surrounding pixels. Choosing a specific chroma color will cause some colors that would otherwise be transparent to be fully opaque.