Adobe 38043740 - ColdFusion Standard - Mac Development Manual page 1008

DEVELOPING COLDFUSION 9 APPLICATIONS
Working with Documents, Charts, and Reports
Option Description
Cache Type Sets the cache type. Charts can be cached in memory or to disk. Caching in memory is faster, but more memory
intensive.
Maximum number of Specifies the maximum number of charts to store in the cache. When the limit is reached, the oldest chart in the
images in cache cache is deleted to make room for a new one. The maximum number of charts you can store in the cache is 250.
Max number of charting Specifies the maximum number of chart requests that can be processed concurrently. The minimum number is
threads 1 and the maximum is 5. Higher numbers are more memory-intensive.
Disk cache location When caching to disk, specifies the directory in which to store the generated charts.
Writing a chart to a variable
In some cases, your application could have charts that are static or charts that, because of the nature of the data input,
take a long time to render. In this scenario, you can create a chart and write it to a variable.
Once written to a variable, other ColdFusion pages can access the variable to display the chart, or you can write the
variable to disk to save the chart to a file. Saving the variable on disk lets you create or update charts only as needed,
rather than every time someone requests a page that contains a chart.
You use the name attribute of the
is not rendered in the browser but is written to the variable.
You can save the chart as an Adobe Flash SWF file, or as a JPEG or PNG image file. If you save the image as a SWF file,
you can pass the variable back to a Flash client using ColdFusion Flash Remoting. For more information, see
the Flash Remoting Service" on page 606.
Note: If you write the chart to a JPEG or PNG file, mouseover tips and URLs embedded in the chart for data drill-down
do not work when you redisplay the image from the file. However, if you save the image as a SWF file, both tips and drill-
down URLs work. For more information on data drill-down, see
Write a chart to a variable and a file
Create a ColdFusion page with the following content:
1
<cfchart name="myChart" format="jpg">
<cfchartseries type="pie">
<cfchartdata item="New Vehicle Sales" value=500000>
<cfchartdata item="Used Vehicle Sales" value=250000>
<cfchartdata item="Leasing" value=300000>
<cfchartdata item="Service" value=400000>
</cfchartseries>
</cfchart>
<cffile
action="WRITE"
file="c:\inetpub\wwwroot\charts\vehicle.jpg"
output="#myChart#">
<img src="/charts/vehicle.jpg" height=240 width=320>
2 Save the page as chartToFile.cfm in myapps under the web root directory.
View the chartToFile.cfm page in your browser.
3
Reviewing the code
The following table describes the highlighted code and its function:
tag to write a chart to a variable. If you specify the name attribute, the chart
cfchart
Last updated 1/20/2012
"Linking charts to URLs" on page 1004.
1003
"Using