fix textarea for full unicode.

lib/widget.js

@@ -1215,15 +1215,15 @@ Screen.prototype.draw = function(start, end) {
               // If we're at the end, we don't have enough space for a
               // double-width. Overwrite it with a space and ignore.
               ch = ' ';
-              o[x][1] = ' ';
+              o[x][1] = '\0';
             } else {
               // ALWAYS refresh double-width chars because this special cursor
               // behavior is needed. There may be a more efficient way of doing
               // this. See above.
-              o[x][1] = ' ';
+              o[x][1] = '\0';
               // Eat the next character by moving forward and marking as a
               // space (which it is).
-              o[++x][1] = ' ';
+              o[++x][1] = '\0';
             }
           }
         }
@@ -5878,8 +5878,17 @@ Textarea.prototype._listener = function(ch, key) {
     done(null, null);
   } else if (key.name === 'backspace') {
     if (this.value.length) {
+      if (this.screen.fullUnicode) {
+        if (this.value[this.value.length - 2]
+            && unicode.isSurrogate(this.value[this.value.length - 2])) {
+          this.value = this.value.slice(0, -2);
+        } else {
           this.value = this.value.slice(0, -1);
         }
+      } else {
+        this.value = this.value.slice(0, -1);
+      }
+    }
   } else if (ch) {
     if (!/^[\x00-\x08\x0b-\x0c\x0e-\x1f\x7f]$/.test(ch)) {
       this.value += ch;

test/widget-eaw.js

@@ -17,6 +17,7 @@ screen = blessed.screen({
 // screen.tput.strings.enter_alt_charset_mode = false;
 
 // var DOUBLE = '杜';
+// '杜'
 var DOUBLE = String.fromCodePoint
   ? String.fromCodePoint(0x675c)
   : String.fromCharCode(0x675c);

test/widget-textarea.js

@@ -2,7 +2,8 @@ var blessed = require('../')
   , screen;
 
 screen = blessed.screen({
-  dump: __dirname + '/logs/textarea.log'
+  dump: __dirname + '/logs/textarea.log',
+  fullUnicode: true
 });
 
 var box = blessed.textarea({