PNG

The Portable Network Graphics (PNG) format is a lossless image format. Its file size is slightly larger than FLASH* and JPEG and significantly larger than SVG*. However, the quality is significantly less than that of these formats. PNG images print only at a low resolution of 72 DPI.

Corda® Server™ uses Javascript* to provide interactivity such as drilldown and hover text in PNG images. In many cases, interactivity is just as good as it is in a Flash* or SVG image. If you prefer not to use Javascript to provide interactivity, Corda Server can provide limited drilldown and hover capabilities via an image map. For more information, see Drill-Down/ Hover/ Roll-Over Data Label Problems with PNG or JPEG Images in the Corda 7 Install and Administration Guide. PNG images cannot show Hover objects or animations.

The PNG format is supported by most Web browsers, including Netscape* browser versions 4.0 or later, and Microsoft* browser versions 4.0.1 or later, and does not require a plugin.

In PopChart® Pro and Corda 7 Enterprise, PNG images are anti-aliased.

Automatic PNG Detection

One significant feature of Corda Server is Automatic PNG Detection. The Corda Server can detect from a client's request whether or not a Web browser supports PNG images. When this feature is enabled, if a client requests an image in the "AUTO" format, Corda Server returns a PNG image if a browser supports PNG, or a JPEG image otherwise.

Automatic PNG Detection (see Automatic PNG Detection in the Corda 7 Install and Administration Guide) must be enabled in the Administration Console for Corda Server to automatically return the most appropriate image format.

embedding a PNG Image using Corda Embedder

If Automatic PNG Detection is enabled, you usually embed a PNG image by requesting an "AUTO" image instead. However, to explicitly request a PNG Corda image, set the Corda Embedder outputType attribute to "PNG." For example, assuming the Corda Embedder object is named myImage, use the following command to set the image format to PNG:

myImage.outputType = "PNG";

embedding a PNG Image in a Web page

If Automatic PNG Detection is enabled, embed a PNG image by requesting an "AUTO" image instead, or explicitly generate a PNG Corda image using the @_PNG server command. For example, the following HTTP request generates a PNG Corda image:

http://<server address>:2001/?@_FILEexamples/bar.itxml@_PNG

If you have enabled Automatic PNG Detection (see Automatic PNG Detection in the Corda 7 Install and Administration Guide), the following request also creates a PNG image, as long as the browser supports PNG:

http://<server address>:2001/?@_FILEexamples/bar.itxml@_AUTO

Embed a PNG image in a Web page simply by making it the source of an image tag. For example, the following image tag embeds the PNG image we created with the HTTP request above. It also provides an alternate text description of My Corda Image in case the image loads slowly or for the visually impaired.

<img src="http://<server address>:2001/?@_FILEexamples/bar.itxml@_PNG" alt="My Corda Image" />