57 lines
No EOL
1.6 KiB
Elm
57 lines
No EOL
1.6 KiB
Elm
module Transform2D where
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{-| A library for performing [2D matrix transformations](http://en.wikipedia.org/wiki/Transformation_matrix#Affine_transformations).
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It is used primarily with the `groupTransform` function from `Graphics.Collage` and
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allows you to do things like rotation, scaling, translation, shearing, and reflection.
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# Basic Transforms
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@docs identity, matrix, rotation
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# Multiplication
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@docs multiply
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-}
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import Native.Transform2D
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data Transform2D = Transform2D
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{-| Create an identity transform. Transforming by the identity does
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not change anything, but it can come in handy as a default or
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base case.
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/ 1 0 \\
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\\ 0 1 /
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-}
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identity : Transform2D
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identity = Native.Transform2D.identity
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{-| Creates a transformation matrix. This lets you create transforms
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such as scales, shears, reflections, and translations.
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matrix a b c d dx dy
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/ a b \\
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\\ c d /
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And `dx` and `dy` are the translation values.
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-}
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matrix : Float -> Float -> Float -> Float -> Float -> Float -> Transform2D
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matrix = Native.Transform2D.matrix
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{-| Creates a [rotation matrix](http://en.wikipedia.org/wiki/Rotation_matrix).
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Given an angle t, it creates a counterclockwise rotation matrix:
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/ cos t -sin t \\
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\\ sin t cos t /
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-}
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rotation : Float -> Transform2D
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rotation = Native.Transform2D.rotation
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{-| Multiplies two transforms together:
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multiply a b
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/ a11 a12 \\ . / b11 b12 \\
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\\ a21 a22 / \\ b21 b22 /
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-}
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multiply : Transform2D -> Transform2D -> Transform2D
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multiply = Native.Transform2D.multiply |