Controlling Chart Playback

Looping

When you use rChart, you are effectively authoring Flash content, so you sooner or later will have to deal with the Flash player. One of the first issues which will likely surface is controlling the looping behaviour of a Flash animation. This article answers some common questions about controlling looping in Flash animations. In this article, when we refer to the "player", we are referring to Macromedia's Flash player, which is used in web pages and can be used in PowerPoint presentations.

By default, the player will play back your Flash content in an endless loop. Sometimes this is just fine; other times, it just isn't suitable, and you want the player to stop after it plays out your animation once. When Flash is embedded in a web page, or used in PowerPoint, you can set the "loop" property of the player explicitly. It will either loop endlessly (if set to "TRUE"), or only play out once (if set to "FALSE"). However, if you are using the streaming feature of the rChart server component, you (the web designer) don't have access to the player's properties, so you can't alter them. rChart 1.1 addresses this problem by introducing two new workspace properties: Disable Looping, and Force Looping.

If you turn on the Disable Looping property, rChart adds a special instruction to the final frame of the Flash output to stop the player once it gets there. Regardless of whether or not the player is set to loop, it will stop at the last frame. It then requires some user action for the chart to replay - either reloading the chart or manipulating the player's controls.

Similarly, if you turn on the Force Looping property, rChart adds a special instruction to the final frame of the Flash output to send it back to the first frame. Regardless of whether or not the player is set to loop, it will continue to play in an endless loop until the user takes some action.

Disable Looping takes precedence, so if you turn on both Disable Looping and Force Looping (a meaningless condition), the result will be that looping is disabled.

If you want your chart to play out once and stop (leaving the completed chart visible), set the Exit Effect workspace property to "None", otherwise the exit effect will play out and your chart may disappear before playback stops.

Transparent Background

The Flash player includes a transparency setting (WMode="Transparent"). This will make the flash background transparent. There are some issues you should be aware of if you wish to use transparency:

Transparency only appears to be supported in current versions of IE browsers (Netscape does not appear to support it). Also, transparency does not appear to be supported in PowerPoint.
In order to achieve a transparent background in rChart, you must remove any background images from your charts, and each chart's background fill alpha must be set to 0.
When using the player's transparency feature, you should turn off the chart workspace exit effect. As the exit effect is accomplished by overlaying and fading in a colored region, it will produce a result that will likely be undesirable when used in combination with a transparent background.