---

Wired Movies and Sprites

| Previous | Chapter Contents | Chapter Top | Next |

Constant descriptions

kSpriteAtomType

The atom is a parent atom that describes a sprite. It contains atoms that describe properties of the sprite. Optionally, it may also include an atom of type kSpriteNameAtomType that defines the name of the sprite.

kSpriteImagesContainerAtomType

The atom is a parent atom that contains atoms of type kSpriteImageAtomType .

kSpriteImageAtomType

The atom is a parent atom that contains an atom of type kSpriteImageDataAtomType . Optionally, it may also include an atom of type kSpriteNameAtomType that defines the name of the image.

kSpriteImageDataAtomType

The atom is a leaf atom that contains image data.

kSpriteSharedDataAtomType

The atom is a parent atom that contains shared sprite data, such as an atom container of type kSpriteImagesContainerAtomType .

kSpriteNameAtomType

The atom is a leaf atom that contains the name of a sprite or an image. The leaf data is composed of one or more ASCII characters.

kSpritePropertyImageIndex

A leaf atom containing the image index property which is of type short . This atom is a child atom of the kSpriteAtom .

kSpritePropertyLayer

A leaf atom containing the layer property which is of type short . This atom is a child atom of the kSpriteAtom .

kSpritePropertyMatrix

A leaf atom containing the matrix property which is of type MatrixRecord . This atom is a child atom of the kSpriteAtom .

kSpritePropertyVisible

A leaf atom containing the visible property which is of type short . This atom is a child atom of the kSpriteAtom .

kSpritePropertyGraphicsMode

A leaf atom containing the matrix property which is of type ModifyerTrackGraphicsModeRecord . This atom is a child atom of the kSpriteAtom .

kSpritePropertyBackgroundColor

A leaf atom containing the background color property which is of type RGBColor . This atom is used in a sprite track's MediaPropertyAtom atom container.

kSpritePropertyOffscreenBitDepth

A leaf atom containing the preferred offscreen bitdepth which is of type short . This atom is used in a sprite track's MediaPropertyAtom atom container.

kSpritePropertySampleFormat

A leaf atom containing the sample format property which is of type short . This atom is used in a sprite track's MediaPropertyAtom atom container.

kSpriteImageRegistrationAtomType

Sprite images have a default registration point of 0, 0. To specify a different point, add an atom of type kSpriteImageRegistrationAtomType as a child atom of the kSpriteImageAtomType and set its leaf data to a FixedPoint value with the desired registration point.

kSpriteImageGroupIDAtomType

Before QuickTime 3, sprites could only display images with the same image description. This restriction has been relaxed, but you must assign group IDs to sets of equivalent images in your key frame sample. For example, if the sample contains ten images where the first two images are equivalent, and the last eight images are equivalent, then you could assign a group ID of 1000 to the first two images, and a group ID of 1001 to the last eight images. This divides the images in the sample into two sets. The actual ID does not matter, it just needs to be a unique positive integer.

Each image in a sprite media key frame sample is assigned to a group. Add an atom of type kSpriteImageGroupIDAtomType as a child of the kSpriteImageAtomType atom and set its leaf data to a long containing the group ID.

The following are new atom types that have been added to QuickTime 4. For each of these, except kSpriteBehaviorsAtomType , you fill in this struct [QTSpriteButtonBehaviorStruct] which contains a value for each of the four states.

kSpriteBehaviorsAtomType, 1

This is the parent atom of kSpriteImageBehaviorAtomType , kSpriteCursorBehaviorAtomType , and kSpriteStatusStringsBehaviorAtomType . For more information about this new atom type, refer to "Sprite Button Behaviors" .

kSpriteImageBehaviorAtomType

Specifies the imageIndex . For more information about this new atom type, refer to "Sprite Button Behaviors" .

kSpriteCursorBehaviorAtomType

Specifies the cursorID . For more information about this new atom type, refer to "Sprite Button Behaviors" .

kSpriteStatusStringsBehaviorAtomType

Specifies an ID of a string variable contained in a sprite track to display in the status area of the browser. For more information about this new atom type, refer to "Sprite Button Behaviors" .

You must assign group IDs to your sprite sample if you want a sprite to display images with non-equivalent image descriptions (i.e., images with different dimensions).

All sprite media--specifically the leaf data in the QT atom containers for sample and sprite track properties--should be written in big-endian format.