Animated GIFs

Animation

Classic cell-based animation, (flip-page Disney animation), is possible through the GIF format. Successive screen images, (cell, frames, etc.) are stored in one GIF file. A GIF animation is downloaded once and 'played' from the client browser cache. The images are displayed in various ways depending upon the animation control settings.

• Cell Location

  The X, Y pixel corrdinates of each animation cell (image) can be specified. This allows for movement to be performed by the browser instead of being drawn into each frame. A traditional cell animations each cell would have the same location, with the movement embedded in the frawings. The pixel coordinates are relative to the cell animation.

• Intercell Delay

  A display delay factor for each individual frame can be specified in 100^ths of a second. This is the amount of time the browser will pause before displaying the next cell image. Care must be taken to not specifiy to low of a value or the animation will 'fly off' the screen before it can be viewed.

• Cell Disposal

  After a cell has been displayed and the intercell delay has elasped an animator may instruct the browser to handle the image in one of several ways:

  • No Disposal

    If an animation sequence uses a common background it need only be rendered once at the beginning of the sequence and the disposal method set to 'N', do not dispose.

  • Previous

    When a common background is being used that is not drawn in each individual cell. Then each cell following the initial background cell should have their disposal method set to 'P', revert to previous.

  • Background

    A Web page can be used as the animation background. In this case each cell must have their disposal method set to 'B', revert to background. The background must be chosen to be the same color for all cell images and set as the transparency color for the animation.

  • Unspecified

    When classic cell animation is used, each cell contains all of the movement and covers the entire animation area then each cell's disposal method must be set to 'U', unspecified. This causes each cell to be removed as the next is rendered.

• Transparent Background

  A color chosen that has the same effect for each cell image of the animation as a transparency color for a single GIF image. All pixels in each cell that are equal to the background color are not drawn when the cell is rendered.

Animated GIF Creation

The following directions will lead you through the process of creating a simple animated GIF text logo.

Once again launch the Paint Shop Pro application if it is not currently executing. Open a new image file in Paint Shop Pro. From the File menu, select New... Set a small image size and fill it with a desired background color, (using the Flood Fill tool). Click on the text tool,

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selecting the font, size and foreground color and enter your text logo. Save the image as a GIF. Erase the previous text, and enter the text again in a slightly different position. Continue until a number of images, (cell animations), have been created.

Locate the GIF Construction Set animated GIF application from the , Program menu. From the File menu, select New and then from the File menu, also select the Animation Wizard... option. The animation wizard dialogs will lead you step-by-step through the process of combining the text log GIFs created in the previous step into a single animated GIF file. (The following link will allow you to view a screen capture of the GIF Construction Set Animation Wizard in a separate window.)

Other types of animation methods are used on the Web, (client-pull, server-push, JAVA), but require a steeper learning overhead and bandwidth than GIF animations.