From 1c13e4841d76e96b7a3da12bc629202e9fd71c5d Mon Sep 17 00:00:00 2001
From: "Martin T. H. Sandsmark" <martin.sandsmark@kde.org>
Date: Sun, 15 Jan 2017 16:48:24 +0100
Subject: [PATCH] Handle surrogate utf16 characters

For our own sanity we (falsely) assume that all surrogate characters are
double width, otherwise we have to go back and reflow the line.

This makes it work better with emojis in vim at least.

REVIEW: 129841
---
 src/Screen.cpp          | 2 +-
 src/konsole_wcwidth.cpp | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/Screen.cpp b/src/Screen.cpp
index d674017b..5438e83b 100644
--- a/src/Screen.cpp
+++ b/src/Screen.cpp
@@ -636,7 +636,7 @@ void Screen::displayCharacter(unsigned short c)
         return;
     } else if (w == 0) {
         const QChar::Category category = QChar(c).category();
-        if (category != QChar::Mark_NonSpacing && category != QChar::Letter_Other) {
+        if (category != QChar::Mark_NonSpacing && category != QChar::Letter_Other && !QChar::isLowSurrogate(c)) {
             return;
         }
         // Find previous "real character" to try to combine with
diff --git a/src/konsole_wcwidth.cpp b/src/konsole_wcwidth.cpp
index 39c23076..212bc1b5 100644
--- a/src/konsole_wcwidth.cpp
+++ b/src/konsole_wcwidth.cpp
@@ -186,8 +186,14 @@ int KONSOLEPRIVATE_EXPORT konsole_wcwidth(quint16 oucs)
     };
 
     /* test for 8-bit control characters */
-    if (ucs == 0)
+    if (ucs == 0 || QChar::isLowSurrogate(ucs))
         return 0;
+
+    /* Always assume double width, otherwise we have to go back and move characters */
+    if (QChar::isHighSurrogate(ucs)) {
+        return 2;
+    }
+
     if (ucs < 32 || (ucs >= 0x7f && ucs < 0xa0))
         return -1;