To animate grouped objects, a bitmap, or symbol, you cannot use a shape tween. In Flash up through version CS3, the approach was to use a motion tween. For example, to animate a symbol, you will generally place an instance of a symbol in one frame, insert a keyframe to copy over that instance to another frame, and then change either the first instance or the second instance in some way. As with creating a shape tween, you then click in the timeline anywhere between the frame containing the first instance and the frame containing the second instance, and then you either (1) select Motion from the drop-down menu for Tween in the Property Inspector, or (2) Right click and select "Create Motion Tween".
Beginning with CS4, what was previously termed a motion tween is now termed a "Classic Tween" (a category that didn't exist before CS4). In CS4, as we have seen with shape tweens, one cannot use the Property Inspector to specify the type of tween, so one uses the right-click method instead.
Tweens transform what is in the initial frame of the tween into what is in the final frame of the tween. If this involvement a change in position, the default tween behavior is to move in a straight line between the initial and final frames of the tween and the change in position per frame is constant. Each of these can be changed in classic tweens:
Motion Guide - CS3: Do a motion tween as above. Click the Add Motion Guide button to add a motion guide layer. As a precaution, you may want to lock the layer involving the tween. In the guide layer, use the pencil tool to draw a path in the initial frame of the tween. Unlock the layer involving the tween and use the selection tool to click on the symbol instance in the first frame of the tween - drag the instance until the registration point of the symbol instance snaps onto the line. Repeat the process using the last frame of the tween. If you test the tween, the tween should now follow the path drawn by the pencil tool rather than the straight line between the beginning and ending points of the tween. The key to getting this to work is to get the symbol instance to "snap" to the path drawn by the Pencil tool.
CS4 and later: Do a classic tween as above. Right click on the layer name of the layer containing the tween and select "Add Classic Motion Guide" (you do not right-click between the first and last frames of the tween as you did to select the tween type; you right click on the layer name). Use the Pen, Pencil, Line, or Brush tool to draw the desired path in this new layer and the steps are as above.
Rate of tween - the rate at which the tween occurs between the two keyframes need not be constant.
CS3: To set a nonconstant rate, two approaches can be used. If you click on the tween layer between the beginning and ending points of the tween, you can (1) click the Edit button in the Property Inspector which will present you with the Ease In/East Out graph. One alters the rate of tween by dragging a point from the 45 degree line either up or down. One can do this for multiple points on the graph, or (2) you can set the Ease In/Ease Out setting in the Property Inspector.
CS4 and later: Click on the tween layer between the beginning and ending points of the tween, in the Property Inspector click on the Ease value and set it - negative values ease in (animation begins slowly and then speeds up) and positive values ease out (begin quickly and then slows down). The maximum setting is +-100; you may not see much difference with absolute values under say 50. The Custom Ease In/Ease Out graph is accessible through clicking the icon to the right of the Ease value. If you want to set the ease in/ease out separately for various properties, you can deselect the "Use one setting for all properties" box and the top and then select a property in the menu.
The quality settings for jpgs in a Flash file can be set globally by selecting File>Publish Settings>Flash. These global settings can be overridden by settings chosen for an individual bitmap. To set the latter, choose File>Import>Import to Library and select the bitmap file. Once the bitmap is brought into the Library, one selects the bitmap and then clicks on the Properties button (third button from the left at the bottom of the Library panel. One can also open the properties screen by double clicking the icon next to the image name in the lower half of the Library or by double clicking the thumbnail picture in the upper half of the Library.
Just like in other graphics programs when one is setting quality settings, one can put the cursor in the Preview window and it will change to a hand. By holding down the mouse button and dragging, one can view different areas of the picture under the proposed quality setting. This technique allows one to evaluate the effect of a proposed quality setting on the aspects of the picture about which one cares the most. Clicking the Test button updates the image shown in the Preview window and the compression information shown at the bottom of the Preview window.
CS3: Although one can animate a bitmap directly using a motion tween, such an animation can only achieve certain changes - e.g. change in position, rotation, size, etc. If one first converts the bitmap to a graphic symbol and then animates the instances of the symbol, the tween can effect other changes, in particular, changes in alpha transparency (e.g. fade in or fade out). This is done by selecting the instance of the symbol and then using the Color dropdown menu in the Property Inspector and choosing Alpha. (Note: If the color dropdown menu does not appear, use the select tool to click away on a blank area of the Stage and then select the instance of the the symbol instead.
CS4 and later: If one attempts to animate a bitmap directly using a Classic Tween, two symbols are created (with names like Tween1 and Tween2; if one does this for additional bitmaps, the names will be Tween3 and Tween 4, etc.) As you can imagine, this process produces two poorly named symbols where one should have one well-named symbol. Instead it is better to convert the bitmap to a symbol, places instances of the symbol in the desired frames, and then use a Classic Tween. As in CS3, you can also do tweens to change alpha transparency. You select the instance of the symbol and in the Style dropdown menu in the Color section of the Property Inspector, choose Alpha and then the appropriate value.
For bitmaps, fade in and fade outs will often be more useful than having the bitmap change position, rotation, size, etc.
The mask layer is a special layer that defines what is visible on the layer beneath it. Only the portions of the masked layer that are beneath shapes in the mask layer will be visible. For example, import a bitmap to the Stage as above. Create a new layer and draw a shape on it. All that remains is to set the properties of the two layers. To do this, one may select the layer, and then choose Modify>Timeline>Layer Properties or by double clicking the icon next to the layer name. The "Masked" alternative will be greyed out until one gives a layer the "Mask" property. The masking will be evident if one choose Control>Test Movie. To make the masking show up on the Stage in design view, lock both layers.
One can do a tween in the mask layer to animate the mask -- e.g. to make the mask get bigger or smaller.
Revised: November 14, 2011. Comments to William Pegram, bill@billpegram.com