Drawing works!

Closes #20. AnimationFrameView is pretty much functional right now.
Further modifications will be scheduled in different issues. Also it
fugures that Painter needs adjusting the bounding rect for pen size.

src/core/painter.cpp

@@ -105,7 +105,8 @@ void Painter::drawLine(const QPoint &p1, const QPoint &p2)
 void Painter::drawRect(const QRect &rect)
 {
     painter.drawRect(rect);
-    m_boundingBox |= rect;
+    int d = -pen().width() / 2;
+    m_boundingBox |= rect.adjusted(d, d, pen().width() + d, pen().width() + d);
 }
 
 /*!

src/core/painter.hpp

@@ -13,9 +13,11 @@ class Painter
 
     const QBrush &brush() const;
     const QPen &pen() const;
+    QPainter::CompositionMode compositionMode() const;
 
     void setBrush(const QBrush &brush);
     void setPen(const QPen &pen);
+    void setCompositionMode(QPainter::CompositionMode mode);
 
     void drawImage(QString fileName);
     void drawPoint(const QPoint &p);
@@ -46,6 +48,11 @@ inline const QPen &Painter::pen() const
     return painter.pen();
 }
 
+inline QPainter::CompositionMode Painter::compositionMode() const
+{
+    return painter.compositionMode();
+}
+
 inline void Painter::setBrush(const QBrush &brush)
 {
     painter.setBrush(brush);
@@ -56,6 +63,11 @@ inline void Painter::setPen(const QPen &pen)
     painter.setPen(pen);
 }
 
+inline void Painter::setCompositionMode(QPainter::CompositionMode mode)
+{
+    painter.setCompositionMode(mode);
+}
+
 inline void Painter::drawPoint(int x, int y)
 {
     drawPoint(QPoint(x, y));

src/tools/dragtool.cpp

@@ -2,6 +2,8 @@
 
 #include <QDebug>
 
+#include <cstdlib>
+
 DragTool::DragTool(QObject *parent) :
     Tool(parent)
 {
@@ -10,9 +12,15 @@ DragTool::DragTool(QObject *parent) :
 
 void DragTool::mouseMoveEvent(ToolMouseMoveEvent *event)
 {
-    if (event->buttons() & Qt::LeftButton) {
+    if (event->buttons() == Qt::LeftButton) {
         view()->translate(event->dViewPos());
         event->accept();
+    } else {
+        lastPoint = event->pos().toPoint();
+        if (event->buttons() == Qt::RightButton)
+            commit();
+        else
+            preview();
     }
 }
 
@@ -25,13 +33,18 @@ void DragTool::wheelEvent(ToolWheelEvent *event)
 
 void DragTool::mousePressEvent(ToolMouseEvent *event)
 {
-    lastPoint = event->pos().toPoint();
-    preview();
-    event->accept();
+    if (event->button() == Qt::RightButton) {
+        lastPoint = event->pos().toPoint();
+        commit();
+        event->accept();
+    }
 }
 
 void DragTool::paint(Painter *painter, bool preview)
 {
-    Q_UNUSED(preview)
-    painter->drawRect(lastPoint.x(), lastPoint.y(), 10, 10);
+    if (preview)
+        painter->setPen(QPen(Qt::black, 3));
+    else
+        painter->setPen(QPen(QColor(rand() % 256, rand() % 256, rand() % 256), 3));
+    painter->drawRect(lastPoint.x(), lastPoint.y(), 30, 30);
 }

src/view/animationframeview.cpp

@@ -78,8 +78,10 @@ AnimationFrameView::AnimationFrameView(QWidget *parent) :
     scene(new QGraphicsScene(this)),
     frameItem(new GraphicsAnimationFrameViewItem(this)),
     m_frame(nullptr),
-    m_activeLayer(nullptr)
+    m_activeLayer(nullptr),
+    m_tool(nullptr)
 {
+    this->setMouseTracking(true);
     scene->addItem(frameItem);
     graphicsView->setScene(scene);
     graphicsView->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
@@ -366,13 +368,14 @@ void AnimationFrameView::layOut()
 
 void AnimationFrameView::revertBackBuffer()
 {
-    qDebug() << lastBackBufferChange;
     Painter painter(backBuffer);
+    painter.setCompositionMode(QPainter::CompositionMode_Source);
     painter.drawCanvas(
         lastBackBufferChange.topLeft(),
         activeLayer()->canvas(),
         lastBackBufferChange
     );
+    frameItem->update(lastBackBufferChange);
     lastBackBufferChange = QRect();
 }
 
@@ -382,7 +385,7 @@ void AnimationFrameView::toolPreview()
     Painter painter(backBuffer);
     m_tool->paint(&painter, true);
     lastBackBufferChange = painter.boundingBox();
-    update();
+    frameItem->update(lastBackBufferChange);
 }
 
 void AnimationFrameView::toolCommit()
@@ -392,10 +395,15 @@ void AnimationFrameView::toolCommit()
     m_tool->paint(&backPainter, false);
 
     Painter *frontPainter = m_activeLayer->newPainter();
-    frontPainter->drawCanvas(lastBackBufferChange.topLeft(), backBuffer, backPainter.boundingBox());
+    frontPainter->drawCanvas(
+        backPainter.boundingBox().topLeft(),
+        backBuffer,
+        backPainter.boundingBox()
+    );
     delete frontPainter;
 
-    update();
+    lastBackBufferChange = QRect();
+    frameItem->update(backPainter.boundingBox());
 }
 
 GraphicsAnimationFrameViewItem::GraphicsAnimationFrameViewItem(
@@ -423,7 +431,8 @@ void GraphicsAnimationFrameViewItem::paint(
     Q_UNUSED(widget)
 
     if (view->frame() != nullptr) {
-        foreach (Layer *layer, view->frame()->layers()) {
+        for (int i = view->frame()->layerCount() - 1; i >= 0; --i) {
+            const Layer *layer = view->frame()->layer(i);
             const Canvas& canvas = (layer != view->activeLayer())
                 ? layer->canvas().pixmap()
                 : view->backBuffer;