From 8a630c9f7a01e24a2ae0d8aae8974d0b5509ad7d Mon Sep 17 00:00:00 2001
From: Manuel Nickschas <sputnick@quassel-irc.org>
Date: Tue, 8 Jul 2008 01:31:07 +0200
Subject: [PATCH] Use QTextLayout for computing word withs rather than a
 homebrew solution

According to my benchmarks, it's very slightly slower (on my machine, on the
order of 10 ms for 500 chatlines). It does make the code much nicer though.
Also we might catch details like kerning or ligatures where our own solution
might have failed.
---
 src/qtui/chatlinemodelitem.cpp | 43 ++++++++++++++--------------------
 src/qtui/chatlinemodelitem.h   |  3 +--
 2 files changed, 19 insertions(+), 27 deletions(-)

diff --git a/src/qtui/chatlinemodelitem.cpp b/src/qtui/chatlinemodelitem.cpp
index 38663bb0..aebde9dd 100644
--- a/src/qtui/chatlinemodelitem.cpp
+++ b/src/qtui/chatlinemodelitem.cpp
@@ -68,38 +68,29 @@ bool ChatLineModelItem::setData(int column, const QVariant &value, int role) {
   return false;
 }
 
-// compute the width of a text snippet
-qreal ChatLineModelItem::snippetWidth(int start, int end, QFontMetricsF *&metrics, int &formatListIdx, int &formatEnd) {
-  qreal width = 0;
-  while(start < end) {
-    if(formatEnd <= start) {
-      formatListIdx++;
-      formatEnd = _contents.formatList.count() > formatListIdx+1 ? _contents.formatList[formatListIdx+1].first
-                                                                 : _contents.plainText.length();
-      metrics = QtUi::style()->fontMetrics(_contents.formatList[formatListIdx].second);
-      Q_ASSERT(formatEnd > start);
-    }
-    int i = qMin(end, formatEnd);
-    width += metrics->width(_contents.plainText.mid(start, i - start));
-    start = i;
-  }
-  return width;
-}
-
 void ChatLineModelItem::computeWrapList() {
   enum Mode { SearchStart, SearchEnd };
 
   QList<ChatLineModel::Word> wplist;  // use a temp list which we'll later copy into a QVector for efficiency
   QTextBoundaryFinder finder(QTextBoundaryFinder::Word, _contents.plainText);
   int idx, oldidx;
-  qreal pxpos = 0;
-  int flistidx = -1;
-  int fmtend = -1;
   bool wordStart = false; bool wordEnd = false;
-  QFontMetricsF *metrics = 0;
   Mode mode = SearchEnd;
   ChatLineModel::Word word;
   word.start = 0;
+  int wordstartx = 0;
+
+  QTextLayout layout(_contents.plainText);
+  QTextOption option;
+  option.setWrapMode(QTextOption::NoWrap);
+  layout.setTextOption(option);
+
+  layout.setAdditionalFormats(QtUi::style()->toTextLayoutList(_contents.formatList, _contents.plainText.length()));
+  layout.beginLayout();
+  QTextLine line = layout.createLine();
+  line.setNumColumns(_contents.plainText.length());
+  layout.endLayout();
+
   do {
     idx = finder.toNextBoundary();
     if(idx < 0) idx = _contents.plainText.length();
@@ -114,9 +105,11 @@ void ChatLineModelItem::computeWrapList() {
       mode = SearchStart;
       continue;
     }
-    // mode == SearchStart
-    word.width = snippetWidth(word.start, oldidx, metrics, flistidx, fmtend);
-    word.trailing = snippetWidth(oldidx, idx, metrics, flistidx, fmtend);
+    int wordendx = line.cursorToX(oldidx);
+    int trailingendx = line.cursorToX(idx);
+    word.width = wordendx - wordstartx;
+    word.trailing = trailingendx - wordendx;
+    wordstartx = trailingendx;
     wplist.append(word);
 
     if(wordStart) {
diff --git a/src/qtui/chatlinemodelitem.h b/src/qtui/chatlinemodelitem.h
index b76ea68e..1018e99d 100644
--- a/src/qtui/chatlinemodelitem.h
+++ b/src/qtui/chatlinemodelitem.h
@@ -39,8 +39,7 @@ class ChatLineModelItem : public MessageModelItem {
 
   private:
     void computeWrapList();
-    qreal snippetWidth(int start, int end, QFontMetricsF *&metrics, int &formatListIdx, int &formatEnd);
-
+s
     struct ChatLinePart {
       QString plainText;
       UiStyle::FormatList formatList;
-- 
2.20.1