From ff8d55f1c07a7a8a92359d4da28a5bfabd8ce0d2 Mon Sep 17 00:00:00 2001
From: Joao Figueiredo <joao.figueiredo@jfig.net>
Date: Wed, 22 Jul 2026 09:44:25 +0100
Subject: [PATCH] feat: add area zoom map control

---
 app.js     | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 styles.css | 55 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 133 insertions(+)

diff --git a/app.js b/app.js
index 5437849..639ad9c 100644
--- a/app.js
+++ b/app.js
@@ -72,12 +72,21 @@ const parcelSearchLayer = new ol.layer.Vector({
   }),
 });
 
+const areaZoomInteraction = new ol.interaction.DragBox({
+  className: "ol-area-zoom-box",
+  condition: ol.events.condition.primaryAction,
+  minArea: 16,
+});
+areaZoomInteraction.setActive(false);
+let areaZoomButton;
+
 const map = new ol.Map({
   target: "map",
   controls: ol.control
     .defaults.defaults({ rotate: false })
     .extend([
       createVisibleLayersExtentControl(),
+      createAreaZoomControl(),
       new ol.control.Rotate({
         autoHide: true,
         label: createNorthPointerIcon(),
@@ -90,6 +99,7 @@ const map = new ol.Map({
     zoom: 7,
   }),
 });
+map.addInteraction(areaZoomInteraction);
 
 let availableLayers = [];
 let selectedLayers = [];
@@ -108,12 +118,25 @@ document.addEventListener("keydown", (event) => {
   if (event.key === "Escape") {
     if (!els.featureModal.hidden) {
       closeFeatureModal();
+    } else if (areaZoomInteraction.getActive()) {
+      setAreaZoomMode(false);
     } else if (!els.appShell.classList.contains("sidebar-is-collapsed")) {
       setSidebarCollapsed(true);
     }
   }
 });
 map.on("singleclick", showFeatureInformation);
+areaZoomInteraction.on("boxend", zoomToSelectedArea);
+areaZoomInteraction.on("boxcancel", () => {
+  // A click or a very short drag is not a selection. Exit on the next frame so
+  // cancelling a drag while disabling the interaction cannot recursively
+  // trigger another cancellation.
+  requestAnimationFrame(() => {
+    if (areaZoomInteraction.getActive()) {
+      setAreaZoomMode(false);
+    }
+  });
+});
 
 loadLayers();
 
@@ -150,6 +173,57 @@ function createVisibleLayersExtentControl() {
   return new ol.control.Control({ element });
 }
 
+function createAreaZoomControl() {
+  const element = document.createElement("div");
+  element.className = "ol-area-zoom ol-unselectable ol-control";
+
+  const button = document.createElement("button");
+  button.type = "button";
+  button.title = "Zoom to area";
+  button.setAttribute("aria-label", "Zoom to area");
+  button.setAttribute("aria-pressed", "false");
+
+  const icon = document.createElement("img");
+  icon.className = "area-zoom-icon";
+  icon.src = "./assets/icons/area-zoom.svg";
+  icon.alt = "";
+  button.append(icon);
+
+  button.addEventListener("click", () => setAreaZoomMode(!areaZoomInteraction.getActive()));
+  element.append(button);
+  areaZoomButton = button;
+
+  return new ol.control.Control({ element });
+}
+
+function setAreaZoomMode(active) {
+  areaZoomInteraction.setActive(active);
+  map.getViewport().classList.toggle("area-zoom-is-active", active);
+  areaZoomButton?.setAttribute("aria-pressed", String(active));
+  areaZoomButton?.setAttribute(
+    "title",
+    active ? "Exit area zoom (Esc)" : "Zoom to area",
+  );
+
+  if (active) {
+    closeFeatureModal();
+  }
+}
+
+function zoomToSelectedArea() {
+  const extent = areaZoomInteraction.getGeometry()?.getExtent();
+
+  if (extent && extent.every(Number.isFinite)) {
+    map.getView().fit(extent, {
+      padding: [64, 64, 64, 64],
+      duration: 500,
+      maxZoom: 19,
+    });
+  }
+
+  setAreaZoomMode(false);
+}
+
 async function searchParcela(event) {
   event.preventDefault();
 
@@ -328,6 +402,10 @@ function syncSelectedLayers() {
 }
 
 async function showFeatureInformation(event) {
+  if (areaZoomInteraction.getActive()) {
+    return;
+  }
+
   const queryLayers = availableLayers
     .map((layer) => layer.name)
     .filter(
diff --git a/styles.css b/styles.css
index b44fec2..66314e9 100644
--- a/styles.css
+++ b/styles.css
@@ -442,6 +442,56 @@ button:disabled {
   font-size: 1.3rem;
 }
 
+.map-wrap .ol-area-zoom {
+  top: 140px;
+  right: 16px;
+  left: auto;
+  overflow: hidden;
+  background: var(--panel);
+  border: 1px solid var(--panel-border);
+  border-radius: 14px;
+  backdrop-filter: blur(16px);
+  box-shadow: var(--shadow);
+}
+
+.map-wrap .ol-area-zoom button {
+  display: grid;
+  width: 2.0625em;
+  height: 2.0625em;
+  margin: 0;
+  padding: 0;
+  place-items: center;
+  background: linear-gradient(135deg, var(--accent) 0%, #2b9a79 100%);
+  color: #fffefb;
+  font-size: 1.3rem;
+  line-height: 1;
+}
+
+.map-wrap .ol-area-zoom button:hover,
+.map-wrap .ol-area-zoom button:focus,
+.map-wrap .ol-area-zoom button[aria-pressed="true"] {
+  background: linear-gradient(135deg, var(--accent-strong) 0%, var(--accent) 100%);
+  color: #fff;
+  outline: 2px solid rgba(31, 122, 98, 0.35);
+  outline-offset: -2px;
+}
+
+.area-zoom-icon {
+  display: block;
+  width: 1.2em;
+  height: 1.2em;
+  filter: brightness(0) invert(1);
+}
+
+.map-wrap .ol-viewport.area-zoom-is-active {
+  cursor: crosshair;
+}
+
+.map-wrap .ol-area-zoom-box {
+  border-color: var(--accent);
+  background: rgba(31, 122, 98, 0.16);
+}
+
 /* OpenLayers hides this control while the view is north-up. */
 .map-wrap .ol-rotate {
   top: auto;
@@ -497,6 +547,11 @@ button:disabled {
     right: 12px;
   }
 
+  .map-wrap .ol-area-zoom {
+    top: 136px;
+    right: 12px;
+  }
+
   .map-wrap .ol-rotate {
     right: 12px;
     bottom: 12px;