I'll start by mentioning the link to the Google Chart API Developer's Guide. There are so many chart types and options that it's impossible for me to cover them all in a single tip. This link introduces you to all the options available in the Google Chart API. It's also a good idea to check back often because new chart types and options are made available on a regular basis.

To give you a flavor for how the Google Chart API works, I'll create a simple pie chart. Let's start with the format of the URL you need to send from FileMaker Pro to a Web Viewer:

http://chart.apis.google.com/chart?<parameter 1>&<parameter 2>&<parameter n>

You have to modify the format URL to send the parameters for your particular chart and options for a chart to display in a Web Viewer. Here's a URL for a basic pie chart with the minimum number of options (you can type this line into a Web browser to generate a pie chart):

http://chart.apis.google.com/chart?cht=p3&chd=t:60,40,25&chs=600x350

After the initial API call, "cht" refers to the chart type and the type specified is "p3" or 3-dimensional pie chart. Each additional parameter requires an ampersand (&), similar to how parameters are separated by semi-colons in a FileMaker Pro calculation function. The reference to "chd" is for chart data and each value must be separated by a comma. The last parameter or "chs" is the chart size in pixels.

To construct this formula in FileMaker Pro, you want to use fields so the chart can change depending on the current found set or related records or whatever you decide to pass to the Google Chart API. In the example I'm about to show you, the chart type is selected from a global pop-up menu and translated to the Google API parameter using a Case statement. The data for the chart is gathered from a related table using the List function and formatted for Google Charts using the Substitute function. Finally, the height and width of the chart are constructed through a simple reference to two global fields.

"http://chart.apis.google.com/chart?cht=" &

Case(MYTABLE::xChartSelector = "Pie 2D"; "p"; MYTABLE::xChartSelector = "Pie 3D"; "p3") & "&chd=t:" &

Substitute(List(CHARTDATA::value); "¶"; ",") &

"&chs=" & MYTABLE::xHeight & "x" & MYTABLE:xWidth

After you have all the tables and fields from this formula in your solution, all you have to do is place the formula in a script using the Set Web Viewer script step. It requires you to have a Web Viewer you've named using the Object Naming feature in the Object Info palette. Just use the Go to URL... option on the Set Web Viewer script step and enter the calculation formula above.

It's also possible to gather the values from a field in the found set using a looping script. The script loops through all the records in the found set and assembles them in a comma-separated list:

Freeze Window
Go to Record/Request/Page [First]
Loop
  Set Variable [$chd; Value: CHARTDATA::value & "," & $chd]
  Go to Record/Request/Page [Next; Exit after last]
End Loop
Set Variable [$chd; Value: Left($chd; Length($chd) - 1) //Remove last comma]
Set Web Viewer [Object Name: "Chart"; URL: "see formula below"]

The formula for the Set Web Viewer script step changes to the following to accommodate the looping script:

"http://chart.apis.google.com/chart?cht=" &

Case(MYTABLE::xChartSelector = "Pie 2D"; "p"; MYTABLE::xChartSelector = "Pie 3D"; "p3") & "&chd=t:" &

$chd & //This references the script variable from the looping script

"&chs=" & MYTABLE::xHeight & "x" & MYTABLE:xWidth

If you're comfortable with recursive Custom Functions, you could use a technique published in the October/November 2005 issue. It lets you gather values from a found set more quickly than a looping script without leaving the currently selected record.

Adding API calls to modify the chart is as easy as concatenating. For instance, you could collect the labels for the chart using the List function by simply concatenating another line of code to the end of the formula I previously discussed:

& "&chl=" & Substitute(List(DATA::label); "¶"; "|"))

You can see how easy it is to build a URL to implement different chart options, because all you have to do is concatenate different Google Chart API calls, in no particular order.

I suggest exploring the Google Chart API and familiarizing yourself with the plethora of options so you can better inform your customers or employer on the best possible charting solution for their needs.