histo

Author: Mohammed Sadique

lib/matplotex.ex

@@ -2,6 +2,7 @@ defmodule Matplotex do
   @moduledoc """
   Module to generate a graph.
   """
+  alias Matplotex.Figure.Areal.Histogram
   alias Matplotex.InputError
   alias Matplotex.Figure.Radial.Pie
   alias Matplotex.Figure.Areal.Scatter
@@ -83,6 +84,10 @@ defmodule Matplotex do
     |> LinePlot.create({x, y}, opts)
   end
 
+  def hist(data, bins, opts) do
+    Histogram.create(%Figure{axes: %Histogram{}}, {data, bins}, opts)
+  end
+
   @doc """
   Sets X and Y labels for the graph with given font details
 

lib/matplotex/element/rect.ex

@@ -1,8 +1,9 @@
 defmodule Matplotex.Element.Rect do
   alias Matplotex.Element
 
-  @default_stroke_width 1
-  @default_stroke "rgba(0,0,0,0)"
+  @default_stroke_width 2
+  @default_stroke "black"
+  @default_opacity 1.0
   use Element
 
   @type t :: %__MODULE__{
@@ -22,6 +23,8 @@ defmodule Matplotex.Element.Rect do
     :color,
     :type,
     stroke: @default_stroke,
+    fill_opacity: @default_opacity,
+    stroke_opacity: @default_opacity,
     stroke_width: @default_stroke_width
   ]
 
@@ -37,6 +40,8 @@ defmodule Matplotex.Element.Rect do
       width="#{get_width(rect)}"
       height="#{get_height(rect)}"
       stroke-width="#{rect.stroke_width}"
+      stroke-opacity="#{rect.stroke_opacity}"
+      fill-opacity="#{rect.fill_opacity}"
       filter="">
       </rect>)
   end

lib/matplotex/figure/areal.ex

@@ -4,8 +4,8 @@ defmodule Matplotex.Figure.Areal do
   alias Matplotex.Figure.TwoD
   @callback create(struct(), any(), keyword()) :: struct()
   @callback materialize(struct()) :: struct()
-  @callback plotify(number(), tuple(), number(), number(), list(), atom()) :: number()
   @callback with_legend_handle(struct(), struct()) :: struct()
+  @optional_callbacks with_legend_handle: 2
   defmacro __using__(_) do
     quote do
       @behaviour Matplotex.Figure.Areal

lib/matplotex/figure/areal/bar_chart.ex

@@ -91,7 +91,6 @@ defmodule Matplotex.Figure.Areal.BarChart do
     %Figure{figure | axes: %{axes | element: elements_with_bar}}
   end
 
-  @impl Areal
   def plotify(value, {minl, maxl}, axis_size, transition, _data, :x) do
     s = axis_size / (maxl - minl)
     value * s + transition - minl * s

lib/matplotex/figure/areal/histogram.ex

@@ -0,0 +1,126 @@
+defmodule Matplotex.Figure.Areal.Histogram do
+  alias Matplotex.Element.Rect
+  alias Matplotex.Figure.RcParams
+  alias Matplotex.Figure.Areal.PlotOptions
+  alias Matplotex.Figure.Dataset
+  alias Matplotex.Figure.Areal.Region
+  alias Matplotex.Figure
+  alias Matplotex.Figure.Areal
+  use Areal
+
+  frame(
+    tick: %TwoD{},
+    limit: %TwoD{},
+    label: %TwoD{},
+    region_x: %Region{},
+    region_y: %Region{},
+    region_title: %Region{},
+    region_legend: %Region{},
+    region_content: %Region{}
+  )
+
+  @impl Areal
+  def create(%Figure{axes: %__MODULE__{} = axes} = figure, {data, bins}, opts) do
+    {x, y} = bins_and_hists(data, bins)
+
+    dataset = Dataset.cast(%Dataset{x: x, y: y}, opts)
+
+    %Figure{figure | axes: %__MODULE__{axes | data: {x, y}, dataset: [dataset]}}
+    |> PlotOptions.set_options_in_figure(opts)
+  end
+
+  @impl Areal
+  def materialize(figure) do
+    figure
+    |> sanitize()
+    |> __MODULE__.materialized_by_region()
+    |> materialize_hist()
+  end
+
+  defp materialize_hist(%Figure{axes: %{dataset: data,limit: %TwoD{x: x_lim, y: y_lim}, region_content: %Region{x: x_region_content, y: y_region_content, width: width_region_content, height: height_region_content}, element: element}, rc_params: %RcParams{x_padding: x_padding, white_space: white_space}}) do
+    x_padding_value = width_region_content * x_padding + white_space
+    shrinked_width_region_content = width_region_content - x_padding_value * 2
+
+    hist_elements =
+     data
+     |>Enum.map(fn dataset ->
+      dataset
+      |> do_transform(x_lim, y_lim, shrinked_width_region_content, height_region_content, {x_region_content + x_padding_value, y_region_content})
+      |> capture(abs(y_region_content), shrinked_width_region_content)
+     end)
+     |>List.flatten()
+    %Figure{axes: %{element: element ++ hist_elements}}
+  end
+
+  defp capture(%Dataset{transformed: transformed} = dataset, bly, region_width) do
+    capture(transformed, [], dataset, bly, region_width)
+  end
+
+  defp capture(
+         [{x, y} | to_capture],
+         captured,
+         %Dataset{
+           color: color,
+           x: bins,
+           pos: pos_factor,
+           edge_color: edge_color,
+           alpha: alpha
+         } = dataset,
+         bly,
+         region_width
+       ) do
+    capture(
+      to_capture,
+      captured ++
+        [
+          %Rect{
+            type: "figure.histogram",
+            x: bin_position(x, pos_factor),
+            y: y,
+            width: region_width / length(bins),
+            height: bly - y,
+            color: color,
+            stroke: edge_color,
+            fill_opacity: alpha,
+            stroke_opacity: alpha
+          }
+        ],
+      dataset,
+      bly,
+      region_width
+    )
+  end
+
+  defp capture([], captured, _dataset, _bly, _region_width), do: captured
+
+
+  defp bin_position(x, pos_factor) when pos_factor < 0 do
+    x + pos_factor
+  end
+
+  defp bin_position(x, _pos_factor), do: x
+  defp bins_and_hists(data, bins) do
+    {data_min, data_max} = Enum.min_max(data)
+
+    bins_dist =
+      data_min
+      |> Nx.linspace(data_max, n: bins)
+      |> Nx.to_list()
+
+    {hists, _} =
+      Enum.map_reduce(bins_dist, data_min, fn bin, previous_bin ->
+        frequency = Enum.frequencies_by(data, fn point -> point < bin && point > previous_bin end)
+        {Map.get(frequency, true, 0), bin}
+      end)
+
+    {bins_dist, hists}
+  end
+
+  defp sanitize(%Figure{axes: %__MODULE__{data: {x, y}}= axes} = figure) do
+    {ymin, ymax} = Enum.min_max(y)
+    {xmin, xmax} = Enum.min_max(x)
+    {xmin, xmax} = {floor(xmin), ceil(xmax)}
+
+    %Figure{figure | axes: %__MODULE__{axes | limit: %TwoD{y: {floor(ymin), ceil(ymax)}, x: xlim }}}
+   end
+end

lib/matplotex/figure/areal/plot_options.ex

@@ -117,14 +117,9 @@ defmodule Matplotex.Figure.Areal.PlotOptions do
     %Figure{
       figure
       | axes: axes |> struct(opts) |> cast_two_d_structs(opts)
-        # |>fulfill_tick_and_lim()
     }
   end
 
-  # defp fulfill_tick_and_lim(%{tick: nil, limit: nil} = axes) do
-
-  # end
-
   defp cast_two_d_structs(%{label: label, tick: tick, limit: limit} = axes, opts)
        when is_map(opts) do
     %{

lib/matplotex/figure/dataset.ex

@@ -4,6 +4,8 @@ defmodule Matplotex.Figure.Dataset do
   @default_linestyle "_"
   @default_width 0.2
   @default_marker_size 3.5
+  @default_stroke "black"
+  @default_alpha 1.0
 
   defstruct [
     :label,
@@ -13,6 +15,8 @@ defmodule Matplotex.Figure.Dataset do
     y: [],
     transformed: [],
     color: @default_color,
+    edge_color: @default_stroke,
+    alpha: @default_alpha,
     marker: @default_marker,
     linestyle: @default_linestyle,
     marker_size: @default_marker_size

lib/matplotex/helpers.ex

@@ -307,4 +307,13 @@ defmodule Matplotex.Helpers do
     |> Matplotex.show()
     |> copy()
   end
+
+  def hist() do
+    values = Nx.Random.key(12) |> Nx.Random.normal(0, 1, shape: {1000}) |> elem(0) |> Nx.to_list()
+    bins = 30
+
+    Matplotex.hist(values, bins, x_label: "Value", y_label: "Frequency", title: "Histogram", color: "blue", edge_color: "black", alpha: 0.7)
+    |> Matplotex.show()
+    |> copy()
+  end
 end

test/matplotex/figure/areal/histogram_test.exs

@@ -0,0 +1,31 @@
+defmodule Matplotex.Figure.Areal.HistogramTest do
+  use Matplotex.PlotCase
+  alias Matplotex.Figure.Areal.Histogram
+
+  setup do
+    values = Nx.Random.key(12) |> Nx.Random.normal(0, 1, shape: {1000}) |> elem(0) |> Nx.to_list()
+    bins = 30
+
+    figure =
+      Matplotex.hist(values, bins, x_label: "Value", y_label: "Frequency", title: "Histogram")
+
+    {:ok, %{figure: figure, bins: bins}}
+  end
+
+  describe "materialyze/1" do
+    test "materialyze with elements", %{figure: figure, bins: bins} do
+      assert figure = Histogram.materialize(figure)
+      elements = figure.axes.element
+      assert title = elements |> Enum.filter(fn elem -> elem.type == "figure.title" end) |> hd
+      assert title.text == "Histogram"
+      assert x_label = elements |> Enum.filter(fn elem -> elem.type == "figure.x_label" end) |> hd
+      assert x_label.text == "Value"
+      assert y_label = elements |> Enum.filter(fn elem -> elem.type == "figure.y_label" end) |> hd
+      assert y_label.text == "Frequency"
+      x_ticks = elements |> Enum.filter(fn elem -> elem.type == "figure.x_tick" end)
+      y_ticks = elements |> Enum.filter(fn elem -> elem.type == "figure.y_tick" end)
+      histogram_elements = elements|>Enum.filter(fn elem -> elem.type == "figure.histogram" end)
+      assert length(histogram_elements) == bins
+    end
+  end
+end

test/matplotex_test.exs

@@ -1,4 +1,5 @@
 defmodule MatplotexTest do
+  alias Matplotex.Figure.Dataset
   alias Matplotex.InputError
   use Matplotex.PlotCase
   alias Matplotex.Figure
@@ -272,4 +273,19 @@ defmodule MatplotexTest do
     assert figure.rc_params.x_label_font.font_size == 10
     assert figure.rc_params.y_label_font.font_size == 10
   end
+
+  describe "hist" do
+    test "creates a figure for histogram" do
+      values =
+        Nx.Random.key(12) |> Nx.Random.normal(0, 1, shape: {1000}) |> elem(0) |> Nx.to_list()
+
+      bins = 30
+      figure = Matplotex.hist(values, bins, x_label: "Value", y_label: "Frequency")
+      assert %Dataset{x: x, y: y} = hd(figure.axes.dataset)
+      assert length(x) == bins
+      assert length(y) == bins
+      assert figure.axes.label.x == "Value"
+      assert figure.axes.label.y == "Frequency"
+    end
+  end
 end