Temporarly disable Scintilla's layout cache if word wrap is on and ta…

…b positions are changed. Resolves issue #20.

Update version info and change log.

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Columns++ for Notepad++ -- Releases
 
+## Version 1.0.6 -- March 26th, 2024
+
+* Avoid display errors that could occur when editing a wrapped line containing elastic tabstops. Under certain circumstances, an empty magenta line might appear following the edited line, or text at the end of the line might not be wrapped properly.
+
 ## Version 1.0.5 -- February 29th, 2024
 
 * Correction to support for the new notification planned in Notepad++ 8.6.5.

src/ColumnsPlusPlus.cpp

@@ -40,13 +40,17 @@ struct ElasticProgressInfo {
 
     static constexpr int stepSize = 100;
 
+    Scintilla::LineCache lineCache;
+    enum { LineCacheIgnore, LineCacheRemove, LineCacheRestore } lineCacheStatus;
+
     ElasticProgressInfo(ColumnsPlusPlusData& data, DocumentData& dd) : data(data), dd(dd) {}
 
     Scintilla::Line processed() const { return step * stepSize + (secondTime ? lastNeeded - firstNeeded + 1 : 0); }
     Scintilla::Line objective() const { return lastNeeded - firstNeeded + (lastMonospaceFail < 0 ? 0 : lastMonospaceFail - firstNeeded + 1); }
 
     bool analyzeTabstops();
     bool setTabstops(bool stepless = false);
+
 };
 
 
@@ -126,6 +130,7 @@ void ColumnsPlusPlusData::setTabstops(DocumentData& dd, Scintilla::Line firstNee
     ElasticProgressInfo epi(*this, dd);
     const Scintilla::Line lineCount     = sci.LineCount();
     const Scintilla::Line linesOnScreen = sci.LinesOnScreen();
+    epi.lineCacheStatus = sci.WrapMode() == Scintilla::Wrap::None ? ElasticProgressInfo::LineCacheIgnore : ElasticProgressInfo::LineCacheRemove;
     if (firstNeeded == -1) {
         epi.firstNeeded = sci.FirstVisibleLine();
         epi.lastNeeded  = std::min(epi.firstNeeded + linesOnScreen, lineCount - 1);
@@ -154,6 +159,7 @@ void ColumnsPlusPlusData::setTabstops(DocumentData& dd, Scintilla::Line firstNee
     }
     sci.PointXFromPosition(0);  // This appears to clear a cache from which Scintilla may read a stale value for ChooseCaretX
     sci.ChooseCaretX();
+    if (epi.lineCacheStatus == ElasticProgressInfo::LineCacheRestore) sci.SetLayoutCache(epi.lineCache);
 }
 
 
@@ -209,6 +215,11 @@ bool ElasticProgressInfo::setTabstops(bool stepless) {
                 }
             }
             if (!unchanged) {
+                if (lineCacheStatus == LineCacheRemove) {
+                    lineCache       = sci.LayoutCache();
+                    lineCacheStatus = LineCacheRestore;
+                    sci.SetLayoutCache(Scintilla::LineCache::None);
+                }
                 sci.ClearTabStops(lineNum);
                 for (size_t i = 0; i < tabs.size(); ++i) sci.AddTabStop(lineNum, tabs[i]);
             }