tuning colorshceme

Author: Mohammed Sadique

lib/matplotex/colorscheme/colormap.ex

@@ -3,7 +3,7 @@ defmodule Matplotex.Colorscheme.Colormap do
   defstruct [:color, :offset, opacity: 1]
 
   def viridis do
-    ["#fde725", "#21918c", "#3b528b", "#440154"]
+    ["#FDE725","#6CCE59","#1F9E89", "#482777"]
   end
 
   def plasma do
@@ -26,16 +26,15 @@ defmodule Matplotex.Colorscheme.Colormap do
 
   def make_colormap(colors) do
     size = length(colors)
-
+   offsets =  Nx.linspace(0, 1, n: size)|> Nx.to_list()
     colors
-    |> Enum.with_index()
-    |> Enum.map(&colormap(&1, size))
+    |> Enum.zip(offsets)
+    |> Enum.map(&colormap(&1))
   end
 
   def default_cmap(), do: viridis()
 
-  defp colormap({color, idx}, size) do
-    offset = idx / size * 100
+  defp colormap({color, offset}) do
     %__MODULE__{color: color, offset: offset}
   end
 end

lib/matplotex/colorscheme/garner.ex

@@ -8,7 +8,6 @@ defmodule Matplotex.Colorscheme.Garner do
 
   def garn_color({min, max} = range, point, cmap) when max != min do
     cue = (point - min) / (max - min)
-
     cmap
     |> make_from_cmap()
     |> put_range(range, cue)
@@ -31,27 +30,37 @@ defmodule Matplotex.Colorscheme.Garner do
 
   defp place_edges([preceeding, minor, major, final]) do
     %__MODULE__{
-      preceeding: preceeding.color,
-      minor: minor.color,
-      major: major.color,
-      final: final.color
+      preceeding: {preceeding.color, preceeding.offset},
+      minor: {minor.color, minor.offset},
+      major: {major.color, major.offset},
+      final: {final.color, final.offset}
     }
   end
 
   defp place_edges(_) do
     raise InputError, message: "Invalid colormap"
   end
 
-  defp point_color(%__MODULE__{color_cue: cue, preceeding: preceeding, minor: minor})
-       when cue < minor do
-    minor |> Blender.mix(preceeding, cue) |> Rgb.to_string()
+  defp point_color(%__MODULE__{color_cue: cue, preceeding: {preceeding,preceeding_offset}, minor: {minor, minor_offset}})
+       when cue <= minor_offset do
+
+        cue = mix_perces(cue, preceeding_offset, minor_offset)
+    minor|> Blender.mix(preceeding, cue) |> Rgb.to_string()
   end
 
-  defp point_color(%__MODULE__{color_cue: cue, minor: minor, major: major}) when cue < major do
+  defp point_color(%__MODULE__{color_cue: cue, minor: {minor, minor_offset}, major: {major, major_offset}}) when cue <= major_offset do
+    cue = mix_perces(cue, minor_offset, major_offset)
     major |> Blender.mix(minor, cue) |> Rgb.to_string()
   end
 
-  defp point_color(%__MODULE__{color_cue: cue, major: major, final: final}) when cue >= major do
-    final |> Blender.mix(major) |> Rgb.to_string()
+  defp point_color(%__MODULE__{color_cue: cue, major: {major,major_offset}, final: {final,  final_offset}}) when cue > major_offset do
+  cue = mix_perces(cue, major_offset, final_offset)
+  final|> Blender.mix(major, cue) |> Rgb.to_string()
   end
+
+  defp mix_perces(cue, preceeding, postceeding) when preceeding != postceeding do
+    (cue - preceeding) / (postceeding - preceeding)
+  end
+  defp mix_perces(cue, _, _), do: cue
+
 end

lib/matplotex/element/cmap.ex

@@ -22,7 +22,7 @@ defmodule Matplotex.Element.Cmap do
   end
 
   def tag_stop(%{offset: offset, color: color, opacity: opacity}) do
-    ~s(<stop offset="#{offset}%" style="stop-color:#{color};stop-opacity:#{opacity}" />)
+    ~s(<stop offset="#{offset * 100}%" style="stop-color:#{color};stop-opacity:#{opacity}" />)
   end
 
   def color_gradient(%__MODULE__{container: container} = element) do

lib/matplotex/figure/cast.ex

@@ -557,7 +557,7 @@ defmodule Matplotex.Figure.Cast do
 
             tick_label =
               Label.cast_label(
-                %Label{type: "tick.cmap", x: tick_label_x, y: y_cord_tick, text: tick},
+                %Label{type: "tick.cmap", x: tick_label_x, y: y_cord_tick, text: format_tick_label(tick)},
                 cmap_tick_font
               )