Add image control to download and print map

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add snapshot control to download and print map. #202
+
 ## [v2.2.2] - 2023-09-02
 
 ### Fixed

examples/simple-html-consumer/static/index.html

@@ -36,6 +36,7 @@
       myMap.addBehavior("sidePanel");
       myMap.addBehavior("layerSwitcherInSidePanel");
       myMap.addBehavior("snappingGrid");
+      myMap.addBehavior("snapshot");
 
       // Display popup with coordinates when not clicking a feature.
       myMap.addPopup(function (event) {

package.json

@@ -37,6 +37,7 @@
     "ol-grid": "^1.1.7",
     "ol-layerswitcher": "^3.7.0",
     "ol-popup": "^4.0.0",
-    "ol-side-panel": "^1.0.6"
+    "ol-side-panel": "^1.0.6",
+    "print-js": "^1.6.0"
   }
 }

src/behavior/index.js

@@ -17,4 +17,5 @@ export default {
   rememberLayer: lazyLoadedBehavior('rememberLayer'),
   sidePanel: lazyLoadedBehavior('sidePanel'),
   snappingGrid: lazyLoadedBehavior('snappingGrid'),
+  snapshot: lazyLoadedBehavior('snapshot'),
 };

src/behavior/snapshot.js

@@ -0,0 +1,10 @@
+import Snapshot from '../control/Snapshot/Snapshot';
+
+export default {
+  attach(instance) {
+
+    // Create the Snapshot control and add it to the map.
+    const control = new Snapshot();
+    instance.map.addControl(control);
+  },
+};

src/control/Snapshot/Snapshot.css

@@ -0,0 +1,18 @@
+.ol-snapshot.ol-control {
+  top: 0.5em;
+  right: 6.5em;
+}
+
+.ol-snapshot.ol-control .download,
+.ol-snapshot.ol-control .print {
+  display: none;
+}
+
+.ol-snapshot.ol-control.active .download,
+.ol-snapshot.ol-control.active .print {
+  display: block;
+}
+
+.ol-snapshot.ol-control button {
+  display: inline-block;
+}

src/control/Snapshot/Snapshot.js

@@ -0,0 +1,140 @@
+import Control from 'ol/control/Control';
+import { CLASS_CONTROL, CLASS_UNSELECTABLE } from 'ol/css';
+import EventType from 'ol/events/EventType';
+import MapEventType from 'ol/MapEventType';
+import './Snapshot.css';
+import printJS from 'print-js';
+
+/**
+ * @classdesc
+ * OpenLayers Snapshot Control.
+ *
+ * @api
+ */
+class Snapshot extends Control {
+
+  /**
+   * @param {Options=} opts Snapshot options.
+   */
+  constructor(opts) {
+    const options = opts || {};
+
+    // Call the parent control constructor.
+    super({
+      element: document.createElement('div'),
+      target: options.target,
+    });
+
+    // Create the snapshot button element.
+    const className = options.className || 'ol-snapshot';
+    const button = document.createElement('button');
+    button.innerHTML = options.label || '<svg id="Layer_1" style="enable-background:new 0 0 30 30;" version="1.1" viewBox="0 0 30 30" xml:space="preserve" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g><path d="M6,19V17c0-0.552-0.448-1-1-1H5c-0.552,0-1,0.448-1,1V19c0,0.552,0.448,1,1,1H5C5.552,20,6,19.552,6,19z"/><path d="M10,5L10,5c0,0.553,0.448,1,1,1H13c0.552,0,1-0.448,1-1V5c0-0.552-0.448-1-1-1H11C10.448,4,10,4.448,10,5z"/><path d="M5,14L5,14c0.553,0,1-0.448,1-1V11c0-0.552-0.448-1-1-1H5c-0.552,0-1,0.448-1,1V13C4,13.552,4.448,14,5,14z"/><path d="M23,6h1l0,1c0,0.552,0.448,1,1,1h0c0.552,0,1-0.448,1-1V6c0-1.105-0.895-2-2-2h-1c-0.552,0-1,0.448-1,1v0   C22,5.552,22.448,6,23,6z"/><path d="M16,5L16,5c0,0.552,0.448,1,1,1h2c0.552,0,1-0.448,1-1v0c0-0.552-0.448-1-1-1h-2C16.448,4,16,4.448,16,5z"/><path d="M7,24H6v-1c0-0.552-0.448-1-1-1H5c-0.552,0-1,0.448-1,1v1c0,1.105,0.895,2,2,2h1c0.552,0,1-0.448,1-1V25   C8,24.448,7.552,24,7,24z"/><path d="M6,7V6h1c0.552,0,1-0.448,1-1V5c0-0.552-0.448-1-1-1H6C4.895,4,4,4.895,4,6v1c0,0.552,0.448,1,1,1H5C5.552,8,6,7.552,6,7z"/><path d="M24,11l0,2.001c0,0.552,0.448,1,1,1h0c0.552,0,1-0.448,1-1V11c0-0.552-0.448-1-1-1h0C24.448,10,24,10.448,24,11z"/></g><g><path d="M25,16h-1.764c-0.758,0-1.45-0.428-1.789-1.106l-0.171-0.342C21.107,14.214,20.761,14,20.382,14h-4.764   c-0.379,0-0.725,0.214-0.894,0.553l-0.171,0.342C14.214,15.572,13.521,16,12.764,16H11c-0.552,0-1,0.448-1,1v8c0,0.552,0.448,1,1,1   h14c0.552,0,1-0.448,1-1v-8C26,16.448,25.552,16,25,16z M18,25c-2.209,0-4-1.791-4-4c0-2.209,1.791-4,4-4s4,1.791,4,4   C22,23.209,20.209,25,18,25z"/><circle cx="18" cy="21" r="2"/></g></svg>';
+    button.title = options.tooltip || 'Snapshot';
+    button.className = className;
+    button.type = 'button';
+
+    // Register a click event on the button.
+    button.addEventListener(EventType.CLICK, this.captureImage.bind(this), false);
+
+    // Add the button and CSS classes to the control element.
+    const { element } = this;
+    element.className = `${className} ${CLASS_UNSELECTABLE} ${CLASS_CONTROL}`;
+    element.appendChild(button);
+
+    // Create a download button with link.
+    const link = document.createElement('a');
+    link.setAttribute('download', document.title);
+    link.innerHTML = '<svg height="24" viewBox="0 0 24 24" width="24" xmlns="http://www.w3.org/2000/svg"><path d="M22,16 L22,20 C22,21.1045695 21.1045695,22 20,22 L4,22 C2.8954305,22 2,21.1045695 2,20 L2,16 L4,16 L4,20 L20,20 L20,16 L22,16 Z M13,12.5857864 L16.2928932,9.29289322 L17.7071068,10.7071068 L12,16.4142136 L6.29289322,10.7071068 L7.70710678,9.29289322 L11,12.5857864 L11,2 L13,2 L13,12.5857864 Z" fill-rule="evenodd"/></svg>';
+    this.link = link;
+    const download = document.createElement('button');
+    download.title = 'Download snapshot';
+    download.className = 'download';
+    download.appendChild(link);
+    element.appendChild(download);
+
+    // Create a print button.
+    const print = document.createElement('button');
+    print.innerHTML = '<svg viewBox="0 0 512 512" xmlns="http://www.w3.org/2000/svg"><title/><g><path d="M359,184H147a15,15,0,0,1-15-15V63a15,15,0,0,1,15-15H359a15,15,0,0,1,15,15V169A15,15,0,0,1,359,184ZM162,154H344V78H162Z"/><path d="M359,450H147a15,15,0,0,1-15-15V272.09a15,15,0,0,1,15-15H359a15,15,0,0,1,15,15V435A15,15,0,0,1,359,450ZM162,420H344V287.09H162Z"/><path d="M407.25,379H359a15,15,0,0,1,0-30h48.25a18.9,18.9,0,0,0,18.88-18.88V202.89A18.9,18.9,0,0,0,407.25,184H98.75a18.9,18.9,0,0,0-18.88,18.89V330.12A18.9,18.9,0,0,0,98.75,349H147a15,15,0,0,1,0,30H98.75a48.94,48.94,0,0,1-48.88-48.88V202.89A48.94,48.94,0,0,1,98.75,154h308.5a48.94,48.94,0,0,1,48.88,48.89V330.12A48.94,48.94,0,0,1,407.25,379Z"/><path d="M131,236a14.66,14.66,0,0,1-1.48-.07c-.48-.05-1-.13-1.45-.22s-1-.22-1.43-.36-.93-.31-1.38-.5-.89-.4-1.32-.63a12.45,12.45,0,0,1-1.27-.75c-.4-.27-.8-.56-1.18-.87s-.75-.65-1.1-1-.68-.72-1-1.1a14.34,14.34,0,0,1-.87-1.18q-.41-.62-.75-1.26c-.23-.43-.44-.88-.63-1.33s-.35-.92-.5-1.38-.26-1-.36-1.43-.17-1-.22-1.45a15.68,15.68,0,0,1,0-3c.05-.48.13-1,.22-1.45s.22-1,.36-1.43.31-.93.5-1.38.4-.9.63-1.33.48-.85.75-1.26a14.34,14.34,0,0,1,.87-1.18c.31-.38.65-.75,1-1.1s.72-.68,1.1-1,.78-.6,1.18-.87a12.45,12.45,0,0,1,1.27-.75q.65-.34,1.32-.63c.45-.19.92-.35,1.38-.5s1-.26,1.43-.36,1-.17,1.45-.22a16.15,16.15,0,0,1,2.95,0c.49.05,1,.13,1.46.22s1,.22,1.42.36.94.31,1.39.5.89.4,1.32.63a13.63,13.63,0,0,1,1.27.75c.4.27.8.56,1.18.87s.75.65,1.1,1,.67.72,1,1.1.6.78.87,1.18.52.83.75,1.26.44.88.63,1.33.35.92.5,1.38.26,1,.36,1.43.17,1,.22,1.45a15.68,15.68,0,0,1,0,3c-.05.48-.13,1-.22,1.45s-.22,1-.36,1.43-.31.93-.5,1.38-.4.9-.63,1.33-.48.85-.75,1.26-.57.8-.87,1.18-.65.75-1,1.1-.72.68-1.1,1-.78.6-1.18.87a13.63,13.63,0,0,1-1.27.75q-.65.34-1.32.63c-.45.19-.92.35-1.39.5s-.94.26-1.42.36-1,.17-1.46.22A14.46,14.46,0,0,1,131,236Z"/><path d="M175,236c-.49,0-1,0-1.48-.07s-1-.13-1.45-.22-1-.22-1.43-.36-.93-.31-1.38-.5-.9-.4-1.33-.63-.85-.48-1.26-.75a14.34,14.34,0,0,1-1.18-.87c-.38-.31-.75-.65-1.1-1s-.68-.72-1-1.1-.6-.78-.87-1.18a14.69,14.69,0,0,1-.76-1.27c-.22-.43-.43-.87-.62-1.32s-.35-.92-.5-1.38-.26-1-.36-1.43-.17-1-.22-1.45a15.68,15.68,0,0,1,0-3c.05-.48.13-1,.22-1.45s.22-1,.36-1.43.31-.93.5-1.38.4-.89.62-1.32a14.69,14.69,0,0,1,.76-1.27c.27-.4.56-.8.87-1.18s.65-.75,1-1.1.72-.68,1.1-1a14.34,14.34,0,0,1,1.18-.87q.62-.41,1.26-.75c.43-.23.88-.44,1.33-.63s.92-.35,1.38-.5,1-.26,1.43-.36,1-.17,1.45-.22a16.26,16.26,0,0,1,3,0c.48.05,1,.13,1.45.22s1,.22,1.43.36.93.31,1.38.5.89.4,1.32.63.86.48,1.27.75.8.56,1.18.87.75.65,1.1,1,.67.72,1,1.1.6.78.87,1.18a14.6,14.6,0,0,1,.75,1.27q.34.65.63,1.32c.19.45.35.92.5,1.38s.26,1,.36,1.43.17,1,.22,1.45a15.68,15.68,0,0,1,0,3c-.05.48-.13,1-.22,1.45s-.22,1-.36,1.43-.31.93-.5,1.38-.4.89-.63,1.32a14.6,14.6,0,0,1-.75,1.27c-.27.4-.57.8-.87,1.18s-.65.75-1,1.1-.72.68-1.1,1-.78.6-1.18.87-.84.52-1.27.75-.87.44-1.32.63-.92.35-1.38.5-1,.26-1.43.36-1,.17-1.45.22S175.49,236,175,236Z"/><path d="M312,344H194a15,15,0,0,1,0-30H312a15,15,0,0,1,0,30Z"/><path d="M312,397H194a15,15,0,0,1,0-30H312a15,15,0,0,1,0,30Z"/></g></svg>';
+    print.title = 'Print snapshot';
+    print.className = 'print';
+    print.addEventListener('click', this.printSnapshot.bind(this));
+    element.appendChild(print);
+  }
+
+  /**
+   * Callback to deactivate the snapshot control.
+   * @private
+   */
+  deactivate() {
+    this.element.classList.remove('active');
+  }
+
+  /**
+   * Callback for the snapshot button click event.
+   * @param {MouseEvent} event The event to handle
+   * @private
+   */
+  captureImage(event) {
+    event.preventDefault();
+
+    // Create a new canvas element to combine multiple map canvas data to.
+    const outputCanvas = document.createElement('canvas');
+    const [width, height] = this.getMap().getSize();
+    outputCanvas.width = width;
+    outputCanvas.height = height;
+    const outputContext = outputCanvas.getContext('2d');
+
+    // Draw each canvas from this map into the new canvas.
+    // Logic for transforming and drawing canvases derived from ol export-pdf example.
+    // https://github.com/openlayers/openlayers/blob/6f2ca3b9635f273f6fbddab834bd9126c7d48964/examples/export-pdf.js#L61-L85
+    Array.from(this.getMap().getTargetElement().querySelectorAll('.ol-layer canvas'))
+      .filter(canvas => canvas.width > 0)
+      .forEach((canvas) => {
+        const { opacity } = canvas.parentNode.style;
+        outputContext.globalAlpha = opacity === '' ? 1 : Number(opacity);
+
+        // Get the transform parameters from the style's transform matrix.
+        // This is necessary so that vectors align with raster layers.
+        const { transform } = canvas.style;
+        const matrix = transform
+          .match(/^matrix\(([^(]*)\)$/)[1]
+          .split(',')
+          .map(Number);
+
+        // Apply the transform to the export map context.
+        CanvasRenderingContext2D.prototype.setTransform.apply(
+          outputContext,
+          matrix,
+        );
+        outputContext.drawImage(canvas, 0, 0);
+      });
+
+    // Build a jpeg data url and update link.
+    const url = outputCanvas.toDataURL('image/jpeg');
+    this.link.href = url;
+
+    // Remove the output canvas.
+    outputCanvas.remove();
+
+    // Enable the snapshot actions.
+    this.element.classList.add('active');
+
+    // Subscribe to events to deactivate snapshot actions.
+    this.getMap().on(EventType.CLICK, this.deactivate.bind(this));
+    this.getMap().on(EventType.CHANGE, this.deactivate.bind(this));
+    this.getMap().on(MapEventType.MOVESTART, this.deactivate.bind(this));
+  }
+
+  /**
+   * Callback for the snapshot button click event.
+   * @private
+   */
+  printSnapshot() {
+    if (this.link.href.length) {
+      printJS(this.link.href, 'image');
+    }
+  }
+
+}
+
+export default Snapshot;