There are several options available both for saving chart definitions and exporting charts as image files. More information on how to save and export charts, both in the Chart Designer and using the Chart API, can be found in Chapter 8 - Saving & Exporting Charts and Chapter 10 - EspressChart Chart API.
There are two primary methods which you can use to store chart definitions created in EspressChart: either as chart or as template files.
Chart files save the chart in a binary file called filename.cht. A chart file stores both the definitions of the chart (type, dimension, etc.) as well as the data that was used to create the chart. Hence, chart files are portable. Any time you open a chart file, it will open with the original data that was used to create the chart. After opening the chart, you can refresh the data from the source or change the chart's data source entirely.
Template files save the chart in a binary file called filename.tpl. A template file stores only the chart definitions and stores only 10 records of data with the chart. Hence, any time a template file is opened it will try to connect to the original data source to retrieve the data. Because of this, template files can be less portable than chart files. Template files can also be used to pass chart attributes from one chart to another. To do this, you can apply a template to a chart. This will carry over many of the attributes of the template to the current chart. For more information about applying templates, please see Section 8.1.1 - Working with Templates.
In addition to saving chart definitions in binary format, chart files and template files can also be saved in XML format. These XML chart definition files can be modified outside of Chart Designer or Chart API.
Generally, charts can be deployed via the Web in one of two ways - either as applets or by generating image files. Applets can directly load chart definitions, either template or chart files. For more about using applets see the Chart Viewer section in Chapter 9 - Chart Viewer. For image files, EspressChart can render charts in the following formats:
EspressChart can generate GIF images using one of two compression methods - RLE or LZW. The LZW method is faster and produces smaller files; however, its use is protected by patent. You must obtain a license from Unisys in order to unlock the LZW compression. By default, GIF files are generated using RLE compression.
JPEG is another popular image format. It is a higher resolution image format than GIF and it is not patent protected. When generating a JPEG file you can specify the quality and compression of the file. The higher the quality, the larger the file.
PNG is an image format that is less popular but it can be displayed in most browsers. It is a high-quality image with a smaller file size than JPEG. There are three different compression options available for this format.
SVG (Scalable Vector Graphics) is a relatively new image format that saves the image as vectors in an XML-based text format. Generally, you will need a browser plug-in to view these images.
SWF is an Adobe Flash file. The flash format is vector based and it allows the chart to be resized after export. Also, flash allows for high-resolution printing and produces a small file size.
This is a Windows bitmap format.
WMF is the Windows Meta File format. This can be used for import/export into MS Office documents.
In addition to static images, EspressChart also allows the chart data to be exported as a text file, PDF, or an XML file.