ColdFusion 9.0 Resources

ImageWrite

Description

Writes a ColdFusion image to the specified on-disk or in-memory destination.

Returns

Nothing.

Function syntax

ImageWrite(name [, destination, quality, optional])

History

ColdFusion 8: Added this function.

Parameters

Parameter	Description
`name`	Required. The ColdFusion image on which this operation is performed.
`destination`	Optional. The absolute or relative on-disk or in-memory pathname where you write the file. If you create the image with the `ImageNew` function or another operation where you do not specify the filename, specify the `destination` parameter. The file format is derived from the extension of the filename. The default value for this parameter is the filename of the original image source.
`overwrite`	Optional. If set to `true`, overwrites the destination file.
`quality`	Optional. Defines the JPEG quality used to encode the image. This parameter applies only to destination files with an extension of JPG or JPEG. Valid values are fractions that range from 0 through 1 (the lower the number, the lower the quality). The default value is 0.75.

Usage

Use the following syntax to specify an in-memory file, which is not written to disk. In-memory files speed processing of transient data.

ram:///filepath

The filepath can include directories, for example ram:///petStore/images/poodle.jpg. Create the directories in the path before you specify the file. For more information on using in-memory files, see Optimizing transient files in the Developing ColdFusion Applications.

The file format is derived from the file extension, therefore, use this function to convert images.

For a list of valid formats to write, see the supported image file formats listed in cfimage. To retrieve a list of writable formats on the server where the ColdFusion application is deployed, use the GetWriteableImageFormats function.

Note: Converting images between one file format to another is time-consuming. Also, image quality can degrade; for example, PNG images support 24-bit color, but GIF images support only 256 colors. Converting transparent images (images with alpha) can degrade image quality.

Example

<!--- This example shows how to convert a GIF image to a PNG image. ---> 
<!--- Use the ImageNew function to create a ColdFusion image. ---> 
<cfset myImage = ImageNew("http://www.google.com/images/logo_sm.gif")> 
<!--- Convert the image to a PNG format. ---> 
<cfset ImageWrite(myImage,"google.png")> 
<!--- Display the PNG image. ---> 
<img src="google.png">