From 451eb8c0bfd0eba534807544a2c7a51f3cba6720 Mon Sep 17 00:00:00 2001
From: Yohan Boniface <yohanboniface@free.fr>
Date: Tue, 20 Jun 2023 20:32:40 +0200
Subject: [PATCH] Naive Choropleth legend, WIP

---
 umap/static/umap/js/umap.controls.js |  1 +
 umap/static/umap/js/umap.layer.js    | 13 +++++++++++++
 umap/static/umap/map.css             | 11 +++++++++++
 3 files changed, 25 insertions(+)

diff --git a/umap/static/umap/js/umap.controls.js b/umap/static/umap/js/umap.controls.js
index 66c8849d..ec351921 100644
--- a/umap/static/umap/js/umap.controls.js
+++ b/umap/static/umap/js/umap.controls.js
@@ -598,6 +598,7 @@ L.U.DataLayersControl = L.Control.extend({
 
 L.U.DataLayer.include({
   renderLegend: function (container) {
+    if (this.layer.renderLegend) return this.layer.renderLegend(container)
     const color = L.DomUtil.create('span', 'datalayer-color', container)
     color.style.backgroundColor = this.getColor()
   },
diff --git a/umap/static/umap/js/umap.layer.js b/umap/static/umap/js/umap.layer.js
index 54cdbe23..66f3acfb 100644
--- a/umap/static/umap/js/umap.layer.js
+++ b/umap/static/umap/js/umap.layer.js
@@ -218,6 +218,19 @@ L.U.Layer.Choropleth = L.FeatureGroup.extend({
       ],
     ]
   },
+
+  renderLegend: function (container) {
+    const parent = L.DomUtil.create('ul', '', container)
+    let li, color, label
+
+    this.options.limits.slice(0, -1).forEach((limit, index) => {
+      li = L.DomUtil.create('li', '', parent)
+      color = L.DomUtil.create('span', 'datalayer-color', li)
+      color.style.backgroundColor = this.options.colors[index]
+      label = L.DomUtil.create('span', '', li)
+      label.textContent = `${+this.options.limits[index].toFixed(1)} - ${+this.options.limits[index+1].toFixed(1)}`
+    })
+  },
 })
 
 L.U.Layer.Heat = L.HeatLayer.extend({
diff --git a/umap/static/umap/map.css b/umap/static/umap/map.css
index cef43e39..a35008d1 100644
--- a/umap/static/umap/map.css
+++ b/umap/static/umap/map.css
@@ -1080,6 +1080,17 @@ a.add-datalayer:hover,
     vertical-align: middle;
 }
 
+.datalayer-legend {
+    color: #555;
+    padding: 6px 8px;
+    box-shadow: 0 0 3px rgba(0,0,0,0.2);
+    border-radius: 1px;
+}
+.datalayer-legend ul {
+    list-style-type: none;
+    padding: 0;
+    margin: 0;
+}
 
 /* ********************************* */
 /*           Popup                   */