Actionscript Cookbook

Creating the Components

Components are incredibly useful for developing well-constructed, object-oriented Flash applications. You should consider making elements of a movie into components when they meet either of these criteria:

• The same elements, or similar elements, are used multiple times throughout a movie.

• The element has complex behaviors and can be treated as a discrete unit.

For the image viewer/slideshow application, we will make seven components:

Image

A component that loads images given a URL

ImageViewPane

A component that allows an image to be moved and resized

PreviewPane

A component into which image view panes are added

SequenceViewer

The viewer for the full image slideshow sequence

SequencerItem

One of the thumbnail items that can be added to the sequencer

Sequencer

The component into which thumbnails are added and ordered

Menu

The menu for the application

Designing the Image Element

The preview pane, sequencer, and sequence viewer all include elements that load images. Rather than reinvent the wheel with each, it makes sense to create a single Image component that can be utilized in each case. The Image component should have basic functionality that includes:

• Loading an image from a given URL

• Monitoring load progress with a progress bar

• Invoking a callback function when loading is complete

• Resizing itself to scale (maintaining the aspect ratio) to fit within specific dimensions

To create the Image component, complete the following steps:

1. Create a new movie clip symbol named Image.

2. Edit ...