From 256beee031efef70f4ee750044d9e697d66868bd Mon Sep 17 00:00:00 2001
From: Stephen Blott
Date: Thu, 22 Jan 2015 16:50:58 +0000
Subject: Visual/edit modes: develop edit mode.

- implement "i", "a".
- fix "w" for edit mode.
- try out "e" for enter edit mode.
- initial implementation "o", "O"
- Suppress backspace and delete.
- Scroll in text areas.
---
 lib/dom_utils.coffee | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)

(limited to 'lib/dom_utils.coffee')

diff --git a/lib/dom_utils.coffee b/lib/dom_utils.coffee
index 4f36e395..477abef2 100644
--- a/lib/dom_utils.coffee
+++ b/lib/dom_utils.coffee
@@ -231,5 +231,99 @@ DomUtils =
         @remove()
         false
 
+extend DomUtils,
+  # From: https://github.com/component/textarea-caret-position/blob/master/index.js
+  getCaretCoordinates: do ->
+    # The properties that we copy into a mirrored div.
+    # Note that some browsers, such as Firefox,
+    # do not concatenate properties, i.e. padding-top, bottom etc. -> padding,
+    # so we have to do every single property specifically.
+    properties = [
+      'direction',  # RTL support
+      'boxSizing',
+      'width',  # on Chrome and IE, exclude the scrollbar, so the mirror div wraps exactly as the textarea does
+      'height',
+      'overflowX',
+      'overflowY',  # copy the scrollbar for IE
+
+      'borderTopWidth',
+      'borderRightWidth',
+      'borderBottomWidth',
+      'borderLeftWidth',
+
+      'paddingTop',
+      'paddingRight',
+      'paddingBottom',
+      'paddingLeft',
+
+      # https://developer.mozilla.org/en-US/docs/Web/CSS/font
+      'fontStyle',
+      'fontVariant',
+      'fontWeight',
+      'fontStretch',
+      'fontSize',
+      'fontSizeAdjust',
+      'lineHeight',
+      'fontFamily',
+
+      'textAlign',
+      'textTransform',
+      'textIndent',
+      'textDecoration',  # might not make a difference, but better be safe
+
+      'letterSpacing',
+      'wordSpacing'
+    ]
+
+    `function (element, position, recalculate) {
+      // mirrored div
+      var div = document.createElement('div');
+      div.id = 'input-textarea-caret-position-mirror-div';
+      document.body.appendChild(div);
+
+      var style = div.style;
+      var computed = window.getComputedStyle? getComputedStyle(element) : element.currentStyle;  // currentStyle for IE < 9
+
+      // default textarea styles
+      style.whiteSpace = 'pre-wrap';
+      if (element.nodeName !== 'INPUT')
+        style.wordWrap = 'break-word';  // only for textarea-s
+
+      // position off-screen
+      style.position = 'absolute';  // required to return coordinates properly
+      style.visibility = 'hidden';  // not 'display: none' because we want rendering
+
+      // transfer the element's properties to the div
+      properties.forEach(function (prop) {
+        style[prop] = computed[prop];
+      });
+
+      style.overflow = 'hidden';  // for Chrome to not render a scrollbar; IE keeps overflowY = 'scroll'
+
+      div.textContent = element.value.substring(0, position);
+      // the second special handling for input type="text" vs textarea: spaces need to be replaced with non-breaking spaces - http://stackoverflow.com/a/13402035/1269037
+      if (element.nodeName === 'INPUT')
+        div.textContent = div.textContent.replace(/\s/g, "\u00a0");
+
+      var span = document.createElement('span');
+      // Wrapping must be replicated *exactly*, including when a long word gets
+      // onto the next line, with whitespace at the end of the line before (#7).
+      // The  *only* reliable way to do that is to copy the *entire* rest of the
+      // textarea's content into the <span> created at the caret position.
+      // for inputs, just '.' would be enough, but why bother?
+      span.textContent = element.value.substring(position) || '.';  // || because a completely empty faux span doesn't render at all
+      div.appendChild(span);
+
+      var coordinates = {
+        top: span.offsetTop + parseInt(computed['borderTopWidth']),
+        left: span.offsetLeft + parseInt(computed['borderLeftWidth'])
+      };
+
+      document.body.removeChild(div);
+
+      return coordinates;
+    }
+    `
+
 root = exports ? window
 root.DomUtils = DomUtils
-- 
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