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ColorShade(hexColor, shade)

Last updated March 3, 2010

author

Bob Gray

Version: 0 | Requires: CF5 | Library: UtilityLib

Description:
Returns a lighter hex color if a positive number is used and a darker if a negative number is used. Arguments are a six character hexadecimal value (no #) and the numeric value of how much the color should be incremented. -100 increments the provided color 100% toward black and 100 increments the color 100% toward white. Works well for building gradients using a loop or for generating monochromatic color schemes.

Return Values:
returns a string

Example:

<cfset darkShade = ColorShade("6F23A8", -50)>
<cfset lightShade = ColorShade("6F23A8", 50)>

<cfoutput>
<font color="###darkShade#">#darkShade#</font> is a darker shade of <font color="##6F23A8">6F23A8</font>.<br />
<font color="###lightShade#">#lightShade#</font> is a darker shade of <font color="##6F23A8">6F23A8</font>.<br />
</cfoutput>

Parameters:

Name Description Required
hexColor starting hex color Yes
shade amount hexColor should be incremented(+)/decremented(-) Yes

Full UDF Source:

<!---
 Returns a hexadecimal color value an amount lighter or darker than the provided color.
 
 @param hexColor 	 starting hex color (Required)
 @param shade 	 amount hexColor should be incremented(+)/decremented(-) (Required)
 @return returns a string 
 @author Bob Gray (gray.bob98@gmail.com) 
 @version 0, March 3, 2010 
--->
<cffunction name="ColorShade" returntype="string">

<cfargument name="hexColor" type="string" required="yes">
<cfargument name="shade" type="numeric" required="yes">
    
<cfset var red = "">
<cfset var green = "">
<cfset var blue = "">
<cfset var s = ARGUMENTS.shade>
<cfset var incrementedColor = ""> 

<cfset red = Left(ARGUMENTS.hexColor, 2)>
<cfset green = Mid(ARGUMENTS.hexColor, 3, 2)>
<cfset blue = Right(ARGUMENTS.hexColor, 2)>
	
<cfset red = NumberFormat(InputBaseN(red, 16), 00)>
<cfset green = NumberFormat(InputBaseN(green, 16), 00)>
<cfset blue = NumberFormat(InputBaseN(blue, 16), 00)>	
	
<cfset red = IIF(s LT 0, red * (s + 100) / 100, red + (255 - red) * s / 100)>
<cfset green = IIF(s LT 0, green * (s + 100) / 100, green + (255 - green) * s / 100)>
<cfset blue = IIF(s LT 0, blue * (s + 100) / 100, blue + (255 - blue) * s / 100)>
    
<cfset red = UCase(FormatBaseN(red, 16))>
<cfset green = UCase(FormatBaseN(green, 16))>
<cfset blue = UCase(FormatBaseN(blue, 16))>
    
<cfset red = IIF(Len(red) LT 2, DE(0&red), DE(red))>
<cfset green = IIF(Len(green) LT 2, DE(0&green), DE(green))>
<cfset blue = IIF(Len(blue) LT 2, DE(0&blue), DE(blue))>
    
<cfset incrementedColor = UCase(red&green&blue)>
    
<cfreturn incrementedColor>
    
</cffunction>
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