From 8a7c1f3d0de8009e71454bac445c410b9ef6837d Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Thu, 24 Aug 2023 21:25:57 -0400
Subject: [PATCH] add support for add a highlight for the currently active
 input line to the line number display

---
 tools/lammps-gui/codeeditor.cpp | 27 ++++++++++++++++++++-------
 tools/lammps-gui/codeeditor.h   |  2 ++
 tools/lammps-gui/lammpsgui.cpp  |  8 ++++++++
 3 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/tools/lammps-gui/codeeditor.cpp b/tools/lammps-gui/codeeditor.cpp
index a1e120517d..71d9cfd370 100644
--- a/tools/lammps-gui/codeeditor.cpp
+++ b/tools/lammps-gui/codeeditor.cpp
@@ -28,7 +28,7 @@
 #include <QTextBlock>
 #include <QUrl>
 
-CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent)
+CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent), highlight(-1)
 {
     help_action = new QShortcut(QKeySequence::fromString("Ctrl+?"), parent);
     connect(help_action, &QShortcut::activated, this, &CodeEditor::get_help);
@@ -83,7 +83,7 @@ int CodeEditor::lineNumberAreaWidth()
         ++digits;
     }
 
-    int space = 3 + fontMetrics().horizontalAdvance(QLatin1Char('9')) * digits;
+    int space = 3 + fontMetrics().horizontalAdvance(QLatin1Char('9')) * (digits + 2);
 
     return space;
 }
@@ -94,6 +94,12 @@ void CodeEditor::setFont(const QFont &newfont)
     document()->setDefaultFont(newfont);
 }
 
+void CodeEditor::setHighlight(int block)
+{
+    highlight = block;
+    repaint();
+}
+
 void CodeEditor::updateLineNumberAreaWidth(int /* newBlockCount */)
 {
     setViewportMargins(lineNumberAreaWidth(), 0, 0, 0);
@@ -167,15 +173,22 @@ void CodeEditor::highlightCurrentLine()
 void CodeEditor::lineNumberAreaPaintEvent(QPaintEvent *event)
 {
     QPainter painter(lineNumberArea);
-    painter.fillRect(event->rect(), Qt::lightGray);
     QTextBlock block = firstVisibleBlock();
     int blockNumber  = block.blockNumber();
-    int top          = qRound(blockBoundingGeometry(block).translated(contentOffset()).top());
-    int bottom       = top + qRound(blockBoundingRect(block).height());
+
+    int top    = qRound(blockBoundingGeometry(block).translated(contentOffset()).top());
+    int bottom = top + qRound(blockBoundingRect(block).height());
     while (block.isValid() && top <= event->rect().bottom()) {
         if (block.isVisible() && bottom >= event->rect().top()) {
-            QString number = QString::number(blockNumber + 1);
-            painter.setPen(Qt::black);
+            QString number = QString::number(blockNumber + 1) + " ";
+            if ((highlight < 0) || (blockNumber != highlight)) {
+                painter.setPen(Qt::black);
+            } else {
+                number = QString(">") + QString::number(blockNumber + 1) + "<";
+                painter.fillRect(0, top, lineNumberArea->width(), fontMetrics().height(),
+                                 Qt::darkRed);
+                painter.setPen(Qt::white);
+            }
             painter.drawText(0, top, lineNumberArea->width(), fontMetrics().height(),
                              Qt::AlignRight, number);
         }
diff --git a/tools/lammps-gui/codeeditor.h b/tools/lammps-gui/codeeditor.h
index a6c49ed9db..2ecf8b8f24 100644
--- a/tools/lammps-gui/codeeditor.h
+++ b/tools/lammps-gui/codeeditor.h
@@ -29,6 +29,7 @@ public:
     void lineNumberAreaPaintEvent(QPaintEvent *event);
     int lineNumberAreaWidth();
     void setFont(const QFont &newfont);
+    void setHighlight(int block);
 
 protected:
     void resizeEvent(QResizeEvent *event) override;
@@ -48,6 +49,7 @@ private slots:
 private:
     QWidget *lineNumberArea;
     QShortcut *help_action;
+    int highlight;
 
     QMap<QString, QString> cmd_map;
     QMap<QString, QString> fix_map;
diff --git a/tools/lammps-gui/lammpsgui.cpp b/tools/lammps-gui/lammpsgui.cpp
index 5f1f1e1dda..2fe612817e 100644
--- a/tools/lammps-gui/lammpsgui.cpp
+++ b/tools/lammps-gui/lammpsgui.cpp
@@ -659,6 +659,13 @@ void LammpsGui::logupdate()
         t_remain  = lammps.get_thermo("cpuremain");
         t_total   = t_elapsed + t_remain + 1.0e-10;
         completed = t_elapsed / t_total * 1000.0;
+
+        int nline = -1;
+        void *ptr = lammps.last_thermo("line", 0);
+        if (ptr) {
+            nline = *((int *)ptr);
+            ui->textEdit->setHighlight(nline);
+        }
     }
 
     progress->setValue(completed);
@@ -747,6 +754,7 @@ void LammpsGui::run_done()
     delete logupdater;
     logupdater = nullptr;
     progress->setValue(1000);
+    ui->textEdit->setHighlight(-1);
 
     capturer->EndCapture();
     auto log = capturer->GetCapture();