Diagrams.TwoD.Size

Utilities for working with sizes of two-dimensional objects.

Size and extent of diagrams in R2

Computing sizes

width :: (Enveloped a, V a ~ R2) => a -> Double

Compute the width of an enveloped object.

height :: (Enveloped a, V a ~ R2) => a -> Double

Compute the height of an enveloped object.

size2D :: (Enveloped a, V a ~ R2) => a -> (Double, Double)

Compute the width and height of an enveloped object.

sizeSpec2D :: (Enveloped a, V a ~ R2) => a -> SizeSpec2D

Compute the size of an enveloped object as a SizeSpec2D value.

extentX :: (Enveloped a, V a ~ R2) => a -> Maybe (Double, Double)

Compute the absolute x-coordinate range of an enveloped object in R2, in the form (lo,hi). Return Nothing for objects with an empty envelope.

extentY :: (Enveloped a, V a ~ R2) => a -> Maybe (Double, Double)

Compute the absolute y-coordinate range of an enveloped object in R2, in the form (lo,hi).

center2D :: (Enveloped a, V a ~ R2) => a -> P2

Compute the point at the center (in the x- and y-directions) of a enveloped object. Return the origin for objects with an empty envelope.

Specifying sizes

data SizeSpec2D

A specification of a (requested) rectangular size.

Constructors

Width Double

Specify an explicit width. The height should be determined automatically (so as to preserve aspect ratio).

Height Double

Specify an explicit height. The width should be determined automatically (so as to preserve aspect ratio).

Dims Double Double

An explicit specification of a width and height.

Absolute

Absolute size: use whatever size an object already has; do not rescale.

mkSizeSpec :: Maybe Double -> Maybe Double -> SizeSpec2D

Create a size specification from a possibly-specified width and height.

requiredScaleT :: SizeSpec2D -> (Double, Double) -> Transformation R2

requiredScaleT spec sz returns a transformation (a uniform scale) which can be applied to something of size sz to make it fit the requested size spec, without changing the aspect ratio.

requiredScale :: SizeSpec2D -> (Double, Double) -> Double

requiredScale spec sz returns a scaling factor necessary to make something of size sz fit the requested size spec, without changing the aspect ratio. Hence an explicit specification of both dimensions may not be honored if the aspect ratios do not match; in that case the scaling will be as large as possible so that the object still fits within the requested size.

Changing the size of things

sized :: (Transformable a, Enveloped a, V a ~ R2) => SizeSpec2D -> a -> a

Uniformly scale any enveloped object so that it fits within the given size.

sizedAs :: (Transformable a, Enveloped a, V a ~ R2, Enveloped b, V b ~ R2) => b -> a -> a

Uniformly scale an enveloped object so that it "has the same size as" (fits within the width and height of) some other object.