Add border/casing/line attribute support to svg map keys

app/helpers/svg_helper.rb

@@ -1,7 +1,35 @@
 module SvgHelper
-  def solid_svg_tag(width, height, fill, **options)
-    tag.svg :width => width, :height => height, **options do
-      tag.rect :width => "100%", :height => "100%", :fill => fill
+  def key_svg_tag(**options)
+    border_width = options["border"] ? (options["border-width"] || 1) : 0
+    rect_attrs = {
+      :width => "100%",
+      :height => "100%",
+      :fill => options["fill"] || "none"
+    }
+    if border_width.positive?
+      rect_attrs[:x] = rect_attrs[:y] = format("%g", 0.5 * border_width)
+      rect_attrs[:width] = options["width"] - border_width
+      rect_attrs[:height] = options["height"] - border_width
+    end
+    svg_attrs = options.slice("width", "height", "opacity", :class)
+
+    tag.svg(**svg_attrs) do
+      concat tag.rect(**rect_attrs, **stroke_attrs(options, "border")) if options["fill"] || options["border"]
+      concat tag.line(:x2 => "100%", :y1 => "50%", :y2 => "50%", **stroke_attrs(options, "line")) if options["line"]
+      if options["casing"]
+        casing_width = options["casing-width"] || 1
+        y_top = 0.5 * casing_width
+        y_bottom = options["height"] - (0.5 * casing_width)
+        concat tag.g(tag.line(:x2 => "100%", :y1 => y_top, :y2 => y_top) +
+                     tag.line(:x2 => "100%", :y1 => y_bottom, :y2 => y_bottom),
+                     **stroke_attrs(options, "casing"))
+      end
     end
   end
+
+  private
+
+  def stroke_attrs(attrs, prefix)
+    attrs.select { |key| key.start_with?(prefix) }.transform_keys { |key| key.delete_prefix(prefix).prepend("stroke") }
+  end
 end