Rounded Corners Code

A while back I mentioned that I had come up with some code to do rounded borders, but that I was holding it back as part of a larger release. Since then, I've not gotten as far with some of my other code ideas, and since I was asked nicely, I figured I'd release the code for rounded corners.

It requires a utility function I created for working with images, which in turn requires another utility function... here they are:

<cffunction name="CleanCopy" returntype="any" output="false">
    <cfargument name="image" type="any" required="true" />

    <cfset var myImage = ImageBlank(arguments.image) />
    <cfset ImagePaste(myImage, arguments.image, 0, 0)/>
    <cfreturn myImage/>

<cffunction name="ImageBlank" returntype="Any" output="false" hint="">
    <cfargument name="image" type="any" required="true" />
<cfargument name="backgroundColor" type="string" required="false" default="white" />

<cfset var strInfo = ImageInfo(arguments.image)>
    <cfreturn ImageNew("", strInfo.width, strInfo.height, "argb", arguments.backgroundColor) />

And the meat and bones:

<cffunction name="RoundCorners" returntype="any" output="false" hint="Adds rounded corners to an image.">
    <cfargument name="image" type="any" required="true" />
<cfargument name="cornerSize" type="numeric" required="true" />
<cfargument name="backgroundColor" type="string" required="false" default="white" />
<cfargument name="antialiasingOn" type="boolean" required="false" default="true" />

    <cfset var myImage = CleanCopy(arguments.image) />
    <cfset var strInfo = ImageInfo(myImage) />
    <cfset var strStroke = StructNew() />
    <cfset var xyOffset = (arguments.cornerSize/4)+2 />
    <cfset var arcSize = (1.5*arguments.cornerSize) />
    <cfset strStroke.width = JavaCast("String", arguments.cornerSize/2) />
    <cfset ImageSetDrawingStroke(myImage, strStroke) />
    <cfset ImageSetDrawingColor(myImage, arguments.backgroundColor) />
    <cfif arguments.antialiasingOn>
        <cfset ImageSetAntialiasing(myImage, "on")/>
    <cfset ImageDrawRoundRect(myImage, -xyOffset, -xyOffset, (strInfo.width+strStroke.width+1.5), (strInfo.height+strStroke.width+1.5), arcSize, arcSize, "no")/>

    <cfreturn myImage />        

If you don't need a version that breaks the pass-by-reference nature of images, then delete CleanCopy and ImageBlank and set the first line of RoundCorners to:

<cfset var myImage = arguments.image />

Or change all references of myImage to arguments.image and remove that line of code completely.



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Matt Gifford's Gravatar Jon..

this is fantastic. Thank you so much for posting this and sharing ti with us!
Great work, and a Happy New Year to you! :D

Jon Hartmann, July 2011

I'm Jon Hartmann and I'm a Javascript fanatic, UX/UI evangelist and former ColdFusion master. I blog about mysterious error messages, user interface design questions, and all things baffling and irksome about programming for the web.

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