Kestrel Lua API / Legacy Assets / Images

Macintosh Picture

The MacintoshPicture class is used to load, and manage a PICT resource, and from which an Entity can be spawned.

Macintosh Pictures are one of the Legacy Assets (as in they are a Legacy format, not legacy code) and a fundamental image format supported by Kestrel. They can represent single frame images, or complex sprite sheets.

Be sure to read the documentation of Image Assets and Entities in Kestrel to get a better understanding of how Kestrel handles image assets.

Loading a PICT

Loading a PICT resource (indeed any image asset) is a trivial task in Kestrel. However there are 2 methods of accomplishing this, depending on whether you want to have asset caching or not.

Without Caching

-- Load the PICT of #128
local pict = MacintoshPicture(Resource.id(128))

With Caching

-- Load the PICT of #128
local pict = MacintoshPicture.load(Resource.id(128))

You'll almost always want to use the second option, to avoid having to redecode the image everytime you request it. However if you have an image that appears only once, or infrequently you may opt to use the first option.

Static Methods

The following methods are exposed on the MacintoshPicture class.

Method Name	Return Type	Lua API Version
load(ResourceReference)	MacintoshPicture	v0.0.1

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MacintoshPicture.load(ResourceReference)

Returns a reference to the requested MacintoshPicture from cache, or if the requested picture could not be found, loads and caches the picture before returning a reference to the caller.

Example

local pict = MacintoshPicture.load(Resource.id(128))

Instance Properties

The following properties are exposed on MacintoshPicture.

Property Name	Type	Lua API Version
size	Size	v0.0.1
numberOfSprites	Integer	v0.0.1

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MacintoshPicture.size

Returns a structure that contains the width and the height of an individual sprite within the image. If the image only consists of a single sprite, then this will be the size of the image.

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MacintoshPicture.numberOfSprites

Returns a count for the number of sprites that the image contains. This is calculated internally based upon the underlying size of the image vs the size of an individual sprite, and can not be directly specified.

Instance Methods

The following methods are exposed on the MacintoshPicture instances.

Method Name	Return Type	Lua API Version
spawnEntity(Vec2)	Entity	v0.0.1
setSpriteSize(Size)	None	v0.0.1

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MacintoshPicture:spawnEntity(Vec2)

Returns a new Entity instance at the specified coordinates. The entity is configured to use the image as its sprite sheet.

Example

local ship = battleCruiserSprites.spawnEntity(Vec2(0, 0)) -- ship is an Entity

scene:render(function()
	ship:draw()
end)

---

MacintoshPicture:setSpriteSize(Size)

Specifies the size of a single sprite within the image.