Dactyloidae iOS initial commit

mobile/ios/Client/Assets/NightModeHelper.js

@@ -0,0 +1,132 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+(function() {
+"use strict";
+
+if (!window.__firefox__) {
+  Object.defineProperty(window, '__firefox__', {
+    enumerable: false,
+    configurable: false,
+    writable: false,
+    value: {}
+  });
+}
+
+Object.defineProperty(window.__firefox__, 'NightMode', {
+  enumerable: false,
+  configurable: false,
+  writable: false,
+  value: { enabled: false }
+});
+
+const NIGHT_MODE_INVERT_FILTER_CSS = 'brightness(80%) invert(100%) hue-rotate(180deg)';
+
+const NIGHT_MODE_STYLESHEET = `html {
+  -webkit-filter: hue-rotate(180deg) invert(100%) !important;
+}
+img,video {
+  -webkit-filter: ${NIGHT_MODE_INVERT_FILTER_CSS} !important;
+}`;
+
+var styleElement;
+
+function getStyleElement() {
+  if (styleElement) {
+    return styleElement;
+  }
+
+  styleElement = document.createElement('style');
+  styleElement.type = 'text/css';
+  styleElement.appendChild(document.createTextNode(NIGHT_MODE_STYLESHEET));
+
+  return styleElement;
+}
+
+function applyInvertFilterToChildBackgroundImageElements(parentNode) {
+  parentNode.querySelectorAll('[style*="background"]').forEach(function(el) {
+    if ((el.style.backgroundImage || '').startsWith('url')) {
+      applyInvertFilterToElement(el);
+    }
+  });
+}
+
+function applyInvertFilterToElement(el) {
+  invertedBackgroundImageElements.push(el);
+  el.__firefox__NightMode_originalFilter = el.style.webkitFilter;
+  el.style.webkitFilter = NIGHT_MODE_INVERT_FILTER_CSS;
+}
+
+function removeInvertFilterFromElement(el) {
+  el.style.webkitFilter = el.__firefox__NightMode_originalFilter;
+  delete el.__firefox__NightMode_originalFilter;
+}
+
+var invertedBackgroundImageElements = null;
+
+// Create a `MutationObserver` that checks for new elements
+// added that have a `background-image` in their `style`
+// property/attribute.
+var observer = new MutationObserver(function(mutations) {
+  mutations.forEach(function(mutation) {
+    mutation.addedNodes.forEach(function(node) {
+      if (node.nodeType === Node.ELEMENT_NODE) {
+        applyInvertFilterToChildBackgroundImageElements(node);
+      }
+    });
+  });
+});
+
+Object.defineProperty(window.__firefox__.NightMode, 'setEnabled', {
+  enumerable: false,
+  configurable: false,
+  writable: false,
+  value: function(enabled) {
+    if (enabled === window.__firefox__.NightMode.enabled) {
+      return;
+    }
+
+    window.__firefox__.NightMode.enabled = enabled;
+
+    var styleElement = getStyleElement();
+
+    if (enabled) {
+      invertedBackgroundImageElements = [];
+
+      // Apply the NightMode CSS to the document.
+      document.documentElement.appendChild(styleElement);
+
+      // Add the "invert" CSS class name to all elements with a
+      // `background-image` in their `style` property/attribute.
+      applyInvertFilterToChildBackgroundImageElements(document);
+
+      // Observe for future elements in the document containing
+      // `background-image` in their `style` property/attribute
+      // so that we can also apply the "invert" CSS class name
+      // to them as they are added.
+      observer.observe(document.documentElement, {
+        childList: true,
+        subtree: true
+      });
+      return;
+    }
+
+    // Stop observing for future elements in the document.
+    observer.disconnect();
+
+    // Remove the "invert" CSS class name from all elements
+    // it was previously applied to.
+    invertedBackgroundImageElements.forEach(removeInvertFilterFromElement);
+
+    // Remove the NightMode CSS from the document.
+    var styleElementParentNode = styleElement.parentNode;
+    if (styleElementParentNode) {
+      styleElementParentNode.removeChild(styleElement);
+    }
+
+    invertedBackgroundImageElements = null;
+  }
+});
+
+})();