50 lines
1.4 KiB
Markdown
50 lines
1.4 KiB
Markdown
---
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title: Extending Compass
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layout: tutorial
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crumb: Extending Compass
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classnames:
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- tutorial
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---
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# Extending Compass
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## Sprite engine
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The sprite engine is the work horse of sprite generation it's the interface for assembling and writing the image file to disk.
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## Requirments
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A sprite engine requires only one method and that is `construct_sprite` which must return an object that responds to `save(filepath)`
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Once inside this method you have access to `images` which is a collection of [Compass::SassExtensions::Sprites::Image](http://rdoc.info/github/chriseppstein/compass/dda7c9/Compass/SassExtensions/Sprites/Image)
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Since the Engine module extends base you also have access to all methods in [Compass::SassExtensions::Sprites::Base](http://rdoc.info/github/chriseppstein/compass/dda7c9/Compass/SassExtensions/Sprites/Base)
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### Configuration
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To enable your sprite engine from the config file set
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sprite_engine = :<engine name>
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The example below will load `Compass::SassExtension::Sprites::ChunkyPngEngine`
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sprite_engine = :chunky_png
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### Class Definition
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module Compass
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module SassExtensions
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module Sprites
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module <engine name>Engine
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# Returns an object
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def construct_sprite
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#must return a image object that responds to save(filename)
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end
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end
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end
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end
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end
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