Adobe Flash is a program designed to create presentations and animated cartoons by the combination of three types of animation, known as "tweening" in Flash. The three types of tweening used in Flash are frame-by-frame tweening, motion tweening and shape tweening.
Frame-by-frame animation is the way cartoons have been animated since the early days of animation. Using this method, the animator draws a figure or scene one frame at a time, drawing slight differences between each frame. When the frames are then viewed in rapid sequence, the differences between them create the illusion of change or motion. In Flash, animators impose frame by frame animations over still images or other types of animation to avoid redrawing an entire scene for every animation frame.
Motion tweens transport a still object across a scene. In Flash, an object is animated this way by selecting its start position and first animation frame as well as its end position and last animation frame within the program. When run, the animation displays the object in a different section of the scene for each frame, creating the illusion of motion. Motion tweens are also used to move background images, which creates the illusion that still images in the foreground are in motion. Motion tweens also move two or more objects in a scene relative to each other. This simulates changes in perspective, camera angle and camera distance from the focal point of the scene.
A shape tween changes the shape of an object over a series of frames. In Flash, this is used to accomplish a number of effects. Notably, shape tweens are used to animate opening and closing mouths or blinking eyes. Melting ice cream is created using a shape tween, as are expanding liquid puddles and other similar effects. As with motion tweens, shape tweens are accomplished by placing one shape in one animation frame and another shape in a subsequent end frame. When the animation is played, Flash generates a shape somewhere between the other two in each intermittent frame, creating the image of a smooth transformation between shapes.