first steps for a refactoring overlay system.

As side effect we can now play a bit with visualizing extra selections

src/plugins/texteditor/texteditoroverlay.cpp

@@ -0,0 +1,255 @@
+#include <QtGui/QPainter>
+#include "texteditoroverlay.h"
+#include <QDebug>
+
+using namespace TextEditor;
+using namespace TextEditor::Internal;
+
+
+
+TextEditorOverlay::TextEditorOverlay(BaseTextEditor *editor)
+    :QObject(editor) {
+    m_visible = false;
+    m_borderWidth = 1;
+    m_editor = editor;
+    m_viewport = editor->viewport();
+}
+
+void TextEditorOverlay::update()
+{
+    if (m_visible)
+        m_viewport->update();
+}
+
+
+void TextEditorOverlay::setVisible(bool b)
+{
+    if (m_visible == b)
+        return;
+    m_visible = b;
+    update();
+}
+
+void TextEditorOverlay::clear()
+{
+    m_selections.clear();
+    update();
+}
+
+void TextEditorOverlay::addOverlaySelection(int begin, int end, const QColor &color)
+{
+    if (end <= begin)
+        return;
+
+    QTextDocument *document = m_editor->document();
+
+    OverlaySelection selection;
+    selection.m_color = color;
+
+    selection.m_cursor_begin = QTextCursor(document);
+    selection.m_cursor_begin.setPosition(begin);
+
+    selection.m_cursor_end = QTextCursor(document);
+    selection.m_cursor_end.setPosition(end);
+
+    m_selections += selection;
+    update();
+}
+
+
+void TextEditorOverlay::addOverlaySelection(const QTextCursor &cursor, const QColor &color)
+{
+    if (!cursor.hasSelection())
+        return;
+    addOverlaySelection(cursor.selectionStart(), cursor.selectionEnd(), color);
+}
+
+QRect TextEditorOverlay::rect() const
+{
+    return m_viewport->rect();
+}
+
+void TextEditorOverlay::paintSelection(QPainter *painter, const QTextCursor &begin, const QTextCursor &end, const QColor &color)
+{
+    if (begin.isNull() || end.isNull() || begin.position() > end.position())
+        return;
+
+
+    QPointF offset = m_editor->contentOffset();
+    QRect viewportRect = rect();
+    QTextDocument *document = m_editor->document();
+
+    if (m_editor->blockBoundingGeometry(begin.block()).translated(offset).top() > viewportRect.bottom() + 10
+        || m_editor->blockBoundingGeometry(end.block()).translated(offset).bottom() < viewportRect.top() - 10
+        )
+        return; // nothing of the selection is visible
+
+    QTextBlock block = begin.block();
+
+    bool inSelection = false;
+
+    QVector<QRectF> selection;
+
+    for (; block.isValid() && block.blockNumber() <= end.blockNumber(); block = block.next()) {
+        if (! block.isVisible())
+            continue;
+
+        const QRectF blockGeometry = m_editor->blockBoundingGeometry(block);
+        QTextLayout *blockLayout = block.layout();
+
+        QTextLine line = blockLayout->lineAt(0);
+
+        int beginChar = 0;
+        if (!inSelection) {
+            beginChar = begin.position() - begin.block().position();
+            line = blockLayout->lineForTextPosition(beginChar);
+            inSelection = true;
+        } else {
+            while (beginChar < block.length() && document->characterAt(block.position() + beginChar).isSpace())
+                ++beginChar;
+            if (beginChar == block.length())
+                beginChar = 0;
+        }
+
+        int lastLine = blockLayout->lineCount()-1;
+        int endChar = -1;
+        if (block == end.block()) {
+            endChar = end.position()  - end.block().position();
+            lastLine = blockLayout->lineForTextPosition(endChar).lineNumber();
+            inSelection = false;
+        } else {
+            endChar = block.length();
+            while (endChar > beginChar && document->characterAt(block.position() + endChar - 1).isSpace())
+                --endChar;
+        }
+
+        QRectF lineRect = line.naturalTextRect();
+        if (beginChar < endChar) {
+            lineRect.setLeft(line.cursorToX(beginChar));
+            if (line.lineNumber() == lastLine)
+                lineRect.setRight(line.cursorToX(endChar));
+            selection += lineRect.translated(blockGeometry.topLeft());
+
+            for (int lineIndex = line.lineNumber()+1; lineIndex <= lastLine; ++lineIndex) {
+                line = blockLayout->lineAt(lineIndex);
+                lineRect = line.naturalTextRect();
+                if (lineIndex == lastLine)
+                    lineRect.setRight(line.cursorToX(endChar));
+                selection += lineRect.translated(blockGeometry.topLeft());
+            }
+        } else { // empty lines
+            if (!selection.isEmpty())
+                lineRect.setLeft(selection.last().left());
+            lineRect.setRight(lineRect.left() + 16);
+            selection += lineRect.translated(blockGeometry.topLeft());
+        }
+
+        if (!inSelection)
+            break;
+
+        if (blockGeometry.translated(offset).y() > 2*viewportRect.height())
+            break;
+    }
+
+
+    if (selection.isEmpty())
+        return;
+
+    QVector<QPointF> points;
+
+    const int margin = m_borderWidth/2;
+
+    points += (selection.at(0).topLeft() + selection.at(0).topRight()) / 2 + QPointF(0, -margin);
+    points += selection.at(0).topRight() + QPointF(margin+1, -margin);
+    points += selection.at(0).bottomRight() + QPointF(margin+1, 0);
+
+
+    for(int i = 1; i < selection.count()-1; ++i) {
+
+#define MAX3(a,b,c) qMax(a, qMax(b,c))
+        qreal x = MAX3(selection.at(i-1).right(),
+                       selection.at(i).right(),
+                       selection.at(i+1).right()) + margin;
+
+        points += QPointF(x+1, selection.at(i).top());
+        points += QPointF(x+1, selection.at(i).bottom()+1);
+
+    }
+
+    points += selection.at(selection.count()-1).topRight() + QPointF(margin+1, 0);
+    points += selection.at(selection.count()-1).bottomRight() + QPointF(margin+1, margin+1);
+    points += selection.at(selection.count()-1).bottomLeft() + QPointF(-margin, margin+1);
+    points += selection.at(selection.count()-1).topLeft() + QPointF(-margin, 0);
+
+    for(int i = selection.count()-2; i > 0; --i) {
+#define MIN3(a,b,c) qMin(a, qMin(b,c))
+        qreal x = MIN3(selection.at(i-1).left(),
+                       selection.at(i).left(),
+                       selection.at(i+1).left()) - margin;
+
+        points += QPointF(x, selection.at(i).bottom()+1);
+        points += QPointF(x, selection.at(i).top());
+    }
+
+    points += selection.at(0).bottomLeft() + QPointF(-margin, 1);
+    points += selection.at(0).topLeft() + QPointF(-margin, -margin);
+
+
+    QPainterPath path;
+    const int corner = 4;
+    path.moveTo(points.at(0));
+    points += points.at(0);
+    QPointF previous = points.at(0);
+    for (int i = 1; i < points.size(); ++i) {
+        QPointF point = points.at(i);
+        if (point.y() == previous.y() && qAbs(point.x() - previous.x()) > 2*corner) {
+            QPointF tmp = QPointF(previous.x() + corner * ((point.x() > previous.x())?1:-1), previous.y());
+            path.quadTo(previous, tmp);
+            previous = tmp;
+            i--;
+            continue;
+        } else if (point.x() == previous.x() && qAbs(point.y() - previous.y()) > 2*corner) {
+            QPointF tmp = QPointF(previous.x(), previous.y() + corner * ((point.y() > previous.y())?1:-1));
+            path.quadTo(previous, tmp);
+            previous = tmp;
+            i--;
+            continue;
+        }
+
+
+        QPointF target = (previous + point) / 2;
+        path.quadTo(previous, target);
+        previous = points.at(i);
+    }
+    path.closeSubpath();
+
+    painter->save();
+    QPen pen(color, m_borderWidth);
+    painter->translate(-.5, -.5);
+    QColor brush = color;
+    brush.setAlpha(30);
+    painter->setRenderHint(QPainter::Antialiasing);
+    pen.setJoinStyle(Qt::RoundJoin);
+    painter->setPen(pen);
+    painter->setBrush(brush);
+    path.translate(offset);
+    painter->drawPath(path);
+    painter->restore();
+}
+
+
+void TextEditorOverlay::paint(QPainter *painter, const QRect &clip)
+{
+    Q_UNUSED(clip);
+    for (int i = 0; i < m_selections.size(); ++i) {
+        const OverlaySelection &selection = m_selections.at(i);
+        paintSelection(painter,
+                       selection.m_cursor_begin,
+                       selection.m_cursor_end,
+                       selection.m_color
+                       );
+    }
+}
+
+
+