CodeEditor improvements

- Block (un)indent (works for tabs and or spaces)
- Block indent inserts spaces when m_useTabs == false
- Tabsize based on number of chars (instead of pixels) default size is now 4 chars
- Change fontsize with Ctrl + [-|+|=] (= is same key as +)

pglab/CodeEditor.cpp

@@ -2,6 +2,7 @@
 #include "EditorGutter.h"
 #include <QPainter>
 #include <QTextBlock>
+#include <QDebug>
 //
 // Adapted from codeeditor example
 // http://doc.qt.io/qt-5/qtwidgets-widgets-codeeditor-example.html
@@ -22,6 +23,7 @@ CodeEditor::CodeEditor(QWidget *parent)
 	setWordWrapMode(QTextOption::NoWrap);
 
 	updateGutterAreaWidth(0);
+	setTabSize(4);
 	highlightCurrentLine();
 }
 
@@ -34,7 +36,7 @@ int CodeEditor::gutterAreaWidth()
 		++digits;
 	}
 
-	int space = 3 + fontMetrics().width(QLatin1Char('9')) * (digits + 2);
+	int space = 3 + fontMetrics().horizontalAdvance(QLatin1Char('9')) * (digits + 2);
 
 	return space;
 }
@@ -154,3 +156,118 @@ void CodeEditor::gutterAreaPaintEvent(QPaintEvent *event)
 		++blockNumber;
 	}
 }
+
+void CodeEditor::keyPressEvent(QKeyEvent *e)
+{
+	auto k = e->key();
+	qDebug() << QString("%1").arg(k, 0, 16);
+	if (k == Qt::Key_Tab) {
+		// Function returns false if there was no selection to indent
+		if (indentSelection(true))
+			return;
+	}
+	else if (k == Qt::Key_Backtab) {
+		// Function returns false if there was no selection to indent
+		if (indentSelection(false))
+			return;
+	}
+	else if (k == Qt::Key_Equal || k == Qt::Key_Plus) {
+		if (e->modifiers().testFlag(Qt::ControlModifier)) {
+			auto f = font();
+			f.setPointSize(f.pointSize() + 1);
+			setFont(f);
+		}
+	}
+	else if (k == Qt::Key_Minus) {
+		if (e->modifiers().testFlag(Qt::ControlModifier)) {
+			auto f = font();
+			f.setPointSize(f.pointSize() - 1);
+			setFont(f);
+		}
+	}
+	QPlainTextEdit::keyPressEvent(e);
+}
+
+bool CodeEditor::indentSelection(bool indent)
+{
+	auto cursor = textCursor();
+
+	if(!cursor.hasSelection())
+		return false;
+
+	auto first_pos = cursor.anchor();
+	auto end_pos   = cursor.position();
+
+	if(first_pos > end_pos)
+		std::swap(first_pos, end_pos);
+
+	cursor.setPosition(first_pos, QTextCursor::MoveAnchor);
+	auto start_block = cursor.block().blockNumber();
+
+	cursor.setPosition(end_pos, QTextCursor::MoveAnchor);
+	auto end_block = cursor.block().blockNumber();
+	if (end_block == start_block)
+		return false;
+
+	cursor.beginEditBlock();
+	cursor.setPosition(first_pos, QTextCursor::MoveAnchor);
+	const auto block_count = end_block - start_block;
+	for(int block = 0; block <= block_count; ++block) {
+		cursor.movePosition(QTextCursor::StartOfBlock, QTextCursor::MoveAnchor);
+		if (indent) {
+			if (m_useTab)
+				cursor.insertText("\t");
+			else
+				cursor.insertText(QString(m_tabSize, ' '));
+		}
+		else {
+			// remove tab if there is a tab
+			cursor.movePosition(QTextCursor::EndOfLine, QTextCursor::KeepAnchor);
+			const QString text = cursor.selectedText();
+			int index = 0;
+			int pos = 0;
+			while (pos < m_tabSize && index < text.length()) {
+				QChar c = text[index++];
+				if (c == ' ')
+					++pos;
+				else if (c == '\t')
+					pos = ((pos + m_tabSize) / m_tabSize) * m_tabSize;
+				else {
+					--index;
+					break;
+				}
+			}
+			cursor.movePosition(QTextCursor::StartOfBlock, QTextCursor::MoveAnchor);
+			for (int i = 0; i < index; ++i)
+				cursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor);
+			cursor.removeSelectedText();
+		}
+		cursor.movePosition(QTextCursor::NextBlock, QTextCursor::MoveAnchor);
+	}
+	cursor.endEditBlock();
+
+	cursor.setPosition(first_pos, QTextCursor::MoveAnchor);
+	cursor.movePosition(QTextCursor::StartOfBlock, QTextCursor::MoveAnchor);
+	while(cursor.block().blockNumber() < end_block)
+		cursor.movePosition(QTextCursor::NextBlock, QTextCursor::KeepAnchor);
+
+	cursor.movePosition(QTextCursor::EndOfBlock, QTextCursor::KeepAnchor);
+
+	setTextCursor(cursor);
+	return true;
+}
+
+void CodeEditor::setFont(const QFont &f)
+{
+	QWidget::setFont(f);
+	auto orig_tab = m_tabSize;
+	m_tabSize = 0;
+	setTabSize(orig_tab);
+}
+
+void CodeEditor::setTabSize(int chars)
+{
+	m_tabSize = chars;
+	int pixels = fontMetrics().horizontalAdvance(QString(chars, '0'));
+	this->setTabStopDistance(pixels);
+}