Refactor hvband to use statisitics

Uses existing RectangularBinGeometry. However, RectangularGeometry should be used when it becomes available.

src/geom/hvband.jl

@@ -1,93 +1,28 @@
-using Compose: x_measure, y_measure
+"""
+    Geom.band[(; orientation=:vertical)]
 
-# Band geometry summarizes data as vertical or horizontal bands.
-struct BandGeometry <: Gadfly.GeometryElement
-    orientation::Symbol
-    color::Union{Vector, Color, (Void)}
-    tag::Symbol
-    BandGeometry(orientation, color, tag) = new(orientation, color === nothing ? nothing : Gadfly.parse_colorant(color), tag)
-end
+Draw bands across the plot canvas with a horizontal span specifed by `xmin` and `xmax` if `orientation` is `:vertical`, or a vertical span specified by `ymin` and `ymax` if the `orientation` is `:horizontal`.
 
+This geometry is equivalent to [`Geom.rect`](@ref) with [`Stat.band`](@ref).
+"""
+band(; orientation=:vertical) = RectangularBinGeometry(Stat.band(orientation)) #TODO: use RectangularGeometry when it becomes available.
 
-HBandGeometry(; color = nothing, tag = empty_tag) = BandGeometry(:horizontal, color, tag)
 
 """
-    Geom.hband[(; color=nothing)]
+    Geom.hband[()]
 
 Draw horizontal bands across the plot canvas with a vertical span specified by `ymin` and `ymax` aesthetics.
 
-# Optional Aesthetics
-- `color`:
-  Default is `Theme.default_color`.
+This geometry is equivalent to [`Geom.band`](@ref) with `orientation` set to `:vertical`.
 """
-const hband = HBandGeometry
-
+hband() = band(orientation = :horizontal)
 
-VBandGeometry(; color = nothing, tag = empty_tag) = BandGeometry(:vertical, color, tag)
 
 """
-    Geom.vband[(; color=nothing)]
+    Geom.vband[()]
 
 Draw vertical bands across the plot canvas with a horizontal span specified by `xmin` and `xmax` aesthetics.
 
-# Optional Aesthetics
-- `color`:
-  Default is `Theme.default_color`.
+This geometry is equivalent to [`Geom.band`](@ref).
 """
-const vband = VBandGeometry
-
-
-element_aesthetics(geom::BandGeometry) = geom.orientation == :vertical ?
-            [:xmin, :xmax, :color] : [:ymin, :ymax, :color]
-
-
-# Generate a form for the bad geometry
-#
-# Args:
-#   geom: band geometry.
-#   theme: the plot's theme.
-#   aes: aesthetics.
-#
-# Returns:
-#   A compose Form.
-#
-function render(geom::BandGeometry, theme::Gadfly.Theme, aes::Gadfly.Aesthetics)
-
-    if geom.orientation == :horizontal
-        Gadfly.assert_aesthetics_defined("BandGeometry", aes, :ymin, :ymax)
-        Gadfly.assert_aesthetics_equal_length("BandGeometry", aes, :ymin, :ymax)
-
-        n = max(length(aes.ymin)) #Note: already passed check for equal lengths.
-
-        aes.xmin = fill(0w, n)
-        xwidths = fill(1w, n)
-
-        ywidths = [(y1 - y0) * cy
-                   for (y0, y1) in zip(aes.ymin, aes.ymax)]
-
-    elseif geom.orientation == :vertical
-        Gadfly.assert_aesthetics_defined("BandGeometry", aes, :xmin, :xmax)
-        Gadfly.assert_aesthetics_equal_length("BandGeometry", aes, :xmin, :xmax)
-
-        n = max(length(aes.xmin)) #Note: already passed check for equal lengths.
-
-        aes.ymin = fill(0h, n)
-        ywidths = fill(1h, n)
-
-        xwidths = [(x1 - x0) * cx
-                   for (x0, x1) in zip(aes.xmin, aes.xmax)]
-    else
-        error("Orientation must be :horizontal or :vertical")
-    end
-
-    color = geom.color === nothing ? theme.default_color : geom.color
-
-    return compose!(
-        context(),
-        rectangle(aes.xmin, aes.ymin, xwidths, ywidths, geom.tag),
-        fill(color),
-        stroke(nothing),
-        svgclass("geometry"),
-        svgattribute("shape-rendering", "crispEdges"))
-
-end
+const vband = band