From f4cf464ddb54ef0ebdb5eefa5a7cc8aa73ee64a4 Mon Sep 17 00:00:00 2001
From: fourtf <tf.four@gmail.com>
Date: Sun, 21 Oct 2018 13:03:26 +0200
Subject: [PATCH] fixed issues with surrogate pairs in text selection and
 rendering

---
 src/messages/MessageElement.cpp               | 30 ++++++++++++-------
 src/messages/layouts/MessageLayoutElement.cpp | 13 ++++++--
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/src/messages/MessageElement.cpp b/src/messages/MessageElement.cpp
index 1fd224e64..4412f9de4 100644
--- a/src/messages/MessageElement.cpp
+++ b/src/messages/MessageElement.cpp
@@ -159,7 +159,7 @@ void TextElement::addToContainer(MessageLayoutContainer &container,
         for (Word &word : this->words_) {
             auto getTextLayoutElement = [&](QString text, int width,
                                             bool trailingSpace) {
-                QColor color = this->color_.getColor(*app->themes);
+                auto color = this->color_.getColor(*app->themes);
                 app->themes->normalizeColor(color);
 
                 auto e = (new TextLayoutElement(
@@ -205,26 +205,34 @@ void TextElement::addToContainer(MessageLayoutContainer &container,
             QString text = word.text;
             int textLength = text.length();
             int wordStart = 0;
-            int width = metrics.width(text[0]);
+            int width = 0;
 
-            for (int i = 1; i < textLength; i++) {
-                int charWidth = metrics.width(text[i]);
+            // QChar::isHighSurrogate(text[0].unicode()) ? 2 : 1
 
-                if (!container.fitsInLine(width + charWidth)) {
+            for (int i = 0; i < textLength; i++)  //
+            {
+                auto isSurrogate = text.size() > i + 1 &&
+                                   QChar::isHighSurrogate(text[i].unicode());
+
+                auto charWidth = isSurrogate ? metrics.width(text.mid(i, 2))
+                                             : metrics.width(text[i]);
+
+                if (!container.fitsInLine(width + charWidth))  //
+                {
                     container.addElementNoLineBreak(getTextLayoutElement(
                         text.mid(wordStart, i - wordStart), width, false));
                     container.breakLine();
 
                     wordStart = i;
-                    width = 0;
-                    if (textLength > i + 2) {
-                        width += metrics.width(text[i]);
-                        width += metrics.width(text[i + 1]);
-                        i += 1;
-                    }
+                    width = charWidth;
+
+                    if (isSurrogate) i++;
                     continue;
                 }
+
                 width += charWidth;
+
+                if (isSurrogate) i++;
             }
 
             container.addElement(getTextLayoutElement(
diff --git a/src/messages/layouts/MessageLayoutElement.cpp b/src/messages/layouts/MessageLayoutElement.cpp
index 3b9bfc4e4..b9324aee0 100644
--- a/src/messages/layouts/MessageLayoutElement.cpp
+++ b/src/messages/layouts/MessageLayoutElement.cpp
@@ -214,13 +214,20 @@ int TextLayoutElement::getMouseOverIndex(const QPoint &abs) const
     int x = this->getRect().left();
 
     for (int i = 0; i < this->getText().size(); i++) {
-        int w = metrics.width(this->getText()[i]);
+        auto &text = this->getText();
+        auto width = metrics.width(this->getText()[i]);
+
+        if (x + width > abs.x()) {
+            if (text.size() > i + 1 &&
+                QChar::isLowSurrogate(text[i].unicode()))  //
+            {
+                i++;
+            }
 
-        if (x + w > abs.x()) {
             return i;
         }
 
-        x += w;
+        x += width;
     }
 
     return this->getSelectionIndexCount();