Chroma Filter

  • Article

This topic documents a feature of Visual Filters and Transitions, which is deprecated as of Windows Internet Explorer 9.

Displays a specific color of the content of the object as transparent.

Syntax

HTML
<ELEMENT STYLE="filter:progid:DXImageTransform.Microsoft.Chroma(sProperties)" ... >
Internet Explorer 5.5 or later
Scripting
object.style.filter ="progid:DXImageTransform.Microsoft.Chroma(sProperties)"
Internet Explorer 5.5 or later

Possible Values

sProperties String that specifies one or more properties exposed by the filter.

Members Table

The following table lists the members exposed by the Chroma object.

Attribute Property Description
color Color

Sets or retrieves the value of the color applied with the filter.
enabled Enabled

Sets or retrieves a value that indicates whether the filter is enabled.

Remarks

This effect is not recommended for use with files that have been dithered from 24 bits to 8 bits. In particular, JPEG files, which are dithered and compressed, do not produce a solid chromakey color, resulting in uneven effects.

Chromakey does not work well on antialiased sources in which sharp lines are smoothed by blending the colors of surrounding pixels.

Certain chromakey colors cause some transparent colors to become opaque.

This effect is supported in Microsoft Internet Explorer 4.0. For more information about Internet Explorer 4.0 filter behavior, see Downlevel Support and Internet Explorer 4.0 Filters.

The object that the filter is applied to must have layout before the filter effect displays. You can give the object layout by setting the height or width property, setting the position property to absolute, setting the writingMode property to tb-rl, or setting the contentEditable property to true.

You can assign multiple filters or transitions to an object by declaring each in the filter property of the object. The following div declaration assigns two filters and a Wheel transition to a div element.

<DIV STYLE="width:100%; filter:
    progid:DXImageTransform.Microsoft.MotionBlur(strength=13, direction=310)
    progid:DXImageTransform.Microsoft.Blur(pixelradius=2)
    progid:DXImageTransform.Microsoft.Wheel(duration=3);">
        Blurry text with smudge of gray.</div>

When multiple filters are applied to an object, each filter is processed in source order, with the exception of procedural surfaces, which are computed first. To emphasize a filter's effect, place it last in source order or on the object's parent. Always place transitions last in source order.

Note  As of Internet Explorer 9, the visual effect of this filter is only applied when content is displayed on a screen; the effect is not applied when content is printed.

Examples

The following example shows how to change the effects of this filter by modifying its Color property.

Code example: http://samples.msdn.microsoft.com/workshop/samples/author/filter/Chroma.htm

This example displays colored text within a div object as transparent.


<BUTTON onclick="oFilterDIV.filters.item(
'DXImageTransform.Microsoft.Chroma').color = 'gray';">
    Clear Gray Text, Leave Blue</BUTTON>
<BR/>
<BUTTON onclick="oFilterDIV.filters.item(
'DXImageTransform.Microsoft.Chroma').color = 'blue';">
    Clear Blue Text, Leave Gray</BUTTON>

<P>
<DIV ID="oFilterDIV" STYLE="width:240px; height:100px; 
        filter:progid:DXImageTransform.Microsoft.Chroma(color='yellow'), progid:DXImageTransform.Microsoft.Chroma(color='red')">
    
    <SPAN STYLE="width:240px;color:gray;">
        This text is gray.</SPAN><BR/>
    <SPAN STYLE="width:240px;color:blue;">
        This text is blue.</SPAN>    
</DIV>

Code example: http://samples.msdn.microsoft.com/workshop/samples/author/filter/shortSamples/chromaEX1.htm

Applies To

A, ABBR, ACRONYM, ADDRESS, B, BDO, BIG, BLOCKQUOTE, BODY, BUTTON, CAPTION, CENTER, CITE, CODE, CUSTOM, DD, DEL, DFN, DIR, DIV, DL, DT, EM, FIELDSET, FONT, FORM, FRAME, hn, I, IFRAME, IMG, INPUT type=button, INPUT type=checkbox, INPUT type=file, INPUT type=image, INPUT type=password, INPUT type=radio, INPUT type=reset, INPUT type=submit, INPUT type=text, INS, KBD, LABEL, LEGEND, LI, MARQUEE, MENU, NOBR, OL, OBJECT, P, PLAINTEXT, PRE, Q, RT, RUBY, runtimeStyle, S, SAMP, SMALL, SPAN, STRIKE, STRONG, style, SUB, SUP, TABLE, TD, TEXTAREA, TH, TT, U, UL, VAR, XMP

See Also

Scripting Filters, Filter Design Considerations