Logarithmic epsilon slider (#65)

* log epsilon slider

* Use CSS to hide numbers we do not need

dp_creator_ii/app/analysis_panel.py

@@ -1,3 +1,5 @@
+from math import pow
+
 from shiny import ui, reactive, render
 
 from dp_creator_ii.mock_data import mock_data, ColumnDef
@@ -22,10 +24,8 @@ def analysis_ui():
             "Values above 1 will add less noise to the data, "
             "but have greater risk of revealing individual data."
         ),
-        ui.markdown(
-            "[TODO: Logarithmic slider]"
-            "(https://github.com/opendp/dp-creator-ii/issues/25)"
-        ),
+        ui.input_slider("log_epsilon_slider", None, -1, 1, 0, step=0.1),
+        ui.output_text("epsilon"),
         ui.markdown(
             "## Preview\n"
             "These plots assume a normal distribution for the columns you've selected, "
@@ -39,6 +39,14 @@ def analysis_ui():
 
 
 def analysis_server(input, output, session):
+    @reactive.calc
+    def epsilon_calc():
+        return pow(10, input.log_epsilon_slider())
+
+    @render.text
+    def epsilon():
+        return f"Epsilon: {epsilon_calc():0.3}"
+
     @render.plot()
     def plot_preview():
         min_x = 0

dp_creator_ii/app/css/styles.css

@@ -5,3 +5,8 @@ body {
 #top_level_nav {
     margin-bottom: 1em;
 }
+
+/* Rather than engineer a new widget, hide the numbers we don't want. */
+.irs-min, .irs-max, .irs-single {
+    display: none;
+}