1 files changed, 70 insertions, 0 deletions
diff --git a/ext/fg/js/util.js b/ext/fg/js/util.js
new file mode 100644
index 00000000..eb153e9b
--- /dev/null
+++ b/ext/fg/js/util.js
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2016  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+function getRangeAtPoint(point, lookAhead) {
+    const range = document.caretRangeFromPoint(point.x, point.y);
+    if (range === null) {
+        return null;
+    }
+
+    const node = range.startContainer;
+    if (node.nodeType !== 3 /* TEXT_NODE */) {
+        return null;
+    }
+
+    const offset = range.startOffset;
+    const length = Math.min(node.length - offset, lookAhead);
+    if (length === 0) {
+        return null;
+    }
+
+    range.setEnd(node, offset + length);
+    return range;
+}
+
+function getRangePaddedRect(range) {
+    const node        = range.startContainer;
+    const startOffset = range.startOffset;
+    const endOffset   = range.endOffset;
+
+    range.setStart(node, Math.max(0, startOffset - 1));
+    range.setEnd(node, Math.min(node.length, endOffset + 1));
+    const rect = range.getBoundingClientRect();
+    range.setStart(node, startOffset);
+    range.setEnd(node, endOffset);
+
+    return rect;
+}
+
+function getPopupPositionForRange(popup, range, offset) {
+    const rangeRect = range.getBoundingClientRect();
+    const popupRect = popup.getBoundingClientRect();
+
+    let posX = rangeRect.left;
+    if (posX + popupRect.width >= window.innerWidth) {
+        posX = window.innerWidth - popupRect.width;
+    }
+
+    let posY = rangeRect.bottom + offset;
+    if (posY + popupRect.height >= window.innerHeight) {
+        posY = rangeRect.top - popupRect.height - offset;
+    }
+
+    return {x: posX, y: posY};
+}