Creating A Tiled Image Background With TileImage()

Posted February 13, 2008 at 8:25 AM by Ben Nadel

Tags: ColdFusion

I've added a new function, TileImage(), to Ray Camden's and my ImageUtils.cfc. This new function will completely tile the given graphic onto the given ColdFusion image canvas. Think of this as a repeated background image on a web site or a background pattern on a FireWorks shape. The method looks like this:

TileImage( Image, TileImage [, X [, Y ]] )

Image

The image onto which we are tiling the other image.

TileImage

The image that we are going to be tiling onto our canvas

X

The optional X coordinate from which we are going to start tiling. This defaults to zero but can be set to positive or negative number.

Y

The optional Y coordinate from which we are going to start tiling. This defaults to zero but can be set to positive or negative number.

Let's take a quick look at this baby in action:

  • <!--- Create imageUtils.cfc instance. --->
  • <cfset objUtils = CreateObject( "component", "imageUtils" ).Init() />
  •  
  • <!--- Create a blank canvas. --->
  • <cfset objImage = ImageNew( "", 500, 340, "rgb" ) />
  •  
  • <!--- Read in the image that we are going to tile. --->
  • <cfimage
  • action="read"
  • source="./cute_blonde.jpg"
  • name="objTile"
  • />
  •  
  • <!--- Scale the tile image so that it will tile better. --->
  • <cfimage
  • action="resize"
  • source="#objTile#"
  • height="20%"
  • width="20%"
  • name="objTile"
  • />
  •  
  • <!---
  • Tile the image onto our canvas. You can supply an optional
  • starting X and Y coordniate for the pasting operations; I
  • have included them in this method call and just set them
  • to zero (same as if I didn't include them at all).
  • --->
  • <cfset objUtils.TileImage(
  • objImage,
  • objTile,
  • 0,
  • 0
  • ) />
  •  
  • <!--- Write to broser. --->
  • <cfimage
  • action="writetobrowser"
  • source="#objImage#"
  • />

Here, we are creating a blank canvas and then tiling our cute_blonde.jpg image onto it. We are scaling down the tile image just so that it tiles, otherwise it would be roughly the same size as our blank canvas. Running the above code, we get the following output:


  
  
  

 
TileImage() - Repeated Background Image Using ColdFusion Image Manipulation  
 
  
  

Here is the code for this ColdFusion user define function for image manipulation:

  • <cffunction
  • name="TileImage"
  • access="public"
  • returntype="any"
  • output="false"
  • hint="Takes your ColdFusion image object and tiles the given image over it.">
  •  
  • <!--- Define arguments. --->
  • <cfargument
  • name="Image"
  • type="any"
  • required="true"
  • hint="The ColdFusion image onto which we are going to tile our graphic."
  • />
  •  
  • <cfargument
  • name="TileImage"
  • type="any"
  • required="true"
  • hint="The image that we are going to tile onto our ColdFusion image."
  • />
  •  
  • <cfargument
  • name="X"
  • type="numeric"
  • required="false"
  • default="0"
  • hint="The X point at which we are going to start our tiling."
  • />
  •  
  • <cfargument
  • name="Y"
  • type="numeric"
  • required="false"
  • default="0"
  • hint="The Y point at which we are going to start our tiling."
  • />
  •  
  • <!--- Define the local scope. --->
  • <cfset var LOCAL = {} />
  •  
  •  
  • <!---
  • Check to see what kind of value the tile image is.
  • If it is not an image, then we have to create an
  • image with it such that we can more easily get the
  • height and width dimensions.
  • --->
  • <cfif NOT IsImage( ARGUMENTS.TileImage )>
  •  
  • <!--- Read in the image file. --->
  • <cfimage
  • action="read"
  • source="#ARGUMENTS.TileImage#"
  • name="ARGUMENTS.TileImage"
  • />
  •  
  • </cfif>
  •  
  •  
  • <!--- Get the image dimensions. --->
  • <cfset LOCAL.ImageDimensions = {
  • Width = ImageGetWidth( ARGUMENTS.Image ),
  • Height = ImageGetHeight( ARGUMENTS.Image )
  • } />
  •  
  • <!--- Get the tile image dimensions. --->
  • <cfset LOCAL.TileDimensions = {
  • Width = ImageGetWidth( ARGUMENTS.TileImage ),
  • Height = ImageGetHeight( ARGUMENTS.TileImage )
  • } />
  •  
  •  
  • <!---
  • Now that we have our dimensions, we need to figure
  • out where we need to start tiling. We need to make
  • sure that we start at or before ZERO in both of
  • the axis.
  • --->
  • <cfset LOCAL.StartCoord = {
  • X = ARGUMENTS.X,
  • Y = ARGUMENTS.Y
  • } />
  •  
  • <!--- Find the starting X coord. --->
  • <cfloop condition="(LOCAL.StartCoord.X GT 0)">
  •  
  • <!--- Subtract the width of the tiled image. --->
  • <cfset LOCAL.StartCoord.X -= LOCAL.TileDimensions.Width />
  •  
  • </cfloop>
  •  
  • <!--- Find the starting Y coord. --->
  • <cfloop condition="(LOCAL.StartCoord.Y GT 0)">
  •  
  • <!--- Subtract the width of the tiled image. --->
  • <cfset LOCAL.StartCoord.Y -= LOCAL.TileDimensions.Height />
  •  
  • </cfloop>
  •  
  •  
  • <!---
  • ASSERT: At this point, our StartCoord has the {X,Y}
  • point at which we need to begin our tiling.
  • --->
  •  
  •  
  • <!---
  • Set the current coordindate of pasting to be the
  • start point that we calcualted above. We will be
  • updating this value as we tile the image.
  • --->
  • <cfset LOCAL.PasteCoord = StructCopy( LOCAL.StartCoord ) />
  •  
  • <!---
  • Now, we want to keep looping until the Y coord
  • of our pasting is greater than the heigh of our
  • target ColdFusion image.
  • --->
  • <cfloop
  • index="LOCAL.PasteCoord.Y"
  • from="#LOCAL.StartCoord.Y#"
  • to="#LOCAL.ImageDimensions.Height#"
  • step="#LOCAL.TileDimensions.Height#">
  •  
  • <!---
  • As we loop over the Y coordinate, we want to
  • also keep looping until our X pasting coordinate
  • goes beyond the width of the target ColdFusion
  • image.
  • --->
  • <cfloop
  • index="LOCAL.PasteCoord.X"
  • from="#LOCAL.StartCoord.X#"
  • to="#LOCAL.ImageDimensions.Width#"
  • step="#LOCAL.TileDimensions.Width#">
  •  
  • <!---
  • Paste the tile image onto the target
  • ColdFusion image at the given X,Y
  • coordinate.
  • --->
  • <cfset ImagePaste(
  • ARGUMENTS.Image,
  • ARGUMENTS.TileImage,
  • LOCAL.PasteCoord.X,
  • LOCAL.PasteCoord.Y
  • ) />
  •  
  • </cfloop>
  •  
  • </cfloop>
  •  
  •  
  • <!--- Return the updated image. --->
  • <cfreturn ARGUMENTS.Image />
  • </cffunction>



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