diff --git a/libs/ui/flake/kis_shape_layer.cc b/libs/ui/flake/kis_shape_layer.cc
index a52ab7b08e..8f2cecdb0c 100644
--- a/libs/ui/flake/kis_shape_layer.cc
+++ b/libs/ui/flake/kis_shape_layer.cc
@@ -1,698 +1,701 @@
 /*
  *  Copyright (c) 2006-2008 Boudewijn Rempt <boud@valdyas.org>
  *  Copyright (c) 2007 Thomas Zander <zander@kde.org>
  *  Copyright (c) 2009 Cyrille Berger <cberger@cberger.net>
  *  Copyright (c) 2011 Jan Hambrecht <jaham@gmx.net>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
 #include "kis_shape_layer.h"
 
 #include <QPainter>
 #include <QPainterPath>
 #include <QRect>
 #include <QDomElement>
 #include <QDomDocument>
 #include <QString>
 #include <QList>
 #include <QMap>
 #include <kis_debug.h>
 #include <kundo2command.h>
 #include <commands_new/kis_node_move_command2.h>
 #include <QMimeData>
 
 #include <QTemporaryFile>
 #include <kis_debug.h>
 
 #include <kis_icon.h>
 #include <KoColorSpace.h>
 #include <KoCompositeOp.h>
 #include <KisDocument.h>
 #include <KoUnit.h>
 #include <KoOdf.h>
 #include <KoOdfReadStore.h>
 #include <KoOdfStylesReader.h>
 #include <KoOdfLoadingContext.h>
 #include <KoPageLayout.h>
 #include <KoShapeContainer.h>
 #include <KoShapeLayer.h>
 #include <KoShapeGroup.h>
 #include <KoShapeLoadingContext.h>
 #include <KoShapeManager.h>
 #include <KoSelectedShapesProxy.h>
 #include <KoShapeRegistry.h>
 #include <KoShapeSavingContext.h>
 #include <KoStore.h>
 #include <KoShapeBasedDocumentBase.h>
 #include <KoStoreDevice.h>
 #include <KoViewConverter.h>
 #include <KoXmlNS.h>
 #include <KoXmlReader.h>
 #include <KoXmlWriter.h>
 #include <KoSelection.h>
 #include <KoShapeMoveCommand.h>
 #include <KoShapeTransformCommand.h>
 #include <KoShapeShadow.h>
 #include <KoShapeShadowCommand.h>
 
 #include "SvgWriter.h"
 #include "SvgParser.h"
 
 #include <kis_types.h>
 #include <kis_image.h>
 #include "kis_default_bounds.h"
 #include <kis_paint_device.h>
 #include "kis_shape_layer_canvas.h"
 #include "kis_image_view_converter.h"
 #include <kis_painter.h>
 #include "kis_node_visitor.h"
 #include "kis_processing_visitor.h"
 #include "kis_effect_mask.h"
 #include "commands/KoShapeReorderCommand.h"
 
 #include <SimpleShapeContainerModel.h>
 class ShapeLayerContainerModel : public SimpleShapeContainerModel
 {
 public:
     ShapeLayerContainerModel(KisShapeLayer *parent)
         : q(parent)
 {}
 
     void add(KoShape *child) override {
         SimpleShapeContainerModel::add(child);
 
         /**
          * The shape is always added with the absolute transformation set appropriately.
          * Here we should just squeeze it into the layer's transformation.
          */
         KIS_SAFE_ASSERT_RECOVER_NOOP(inheritsTransform(child));
         if (inheritsTransform(child)) {
             QTransform parentTransform = q->absoluteTransformation(0);
             child->applyAbsoluteTransformation(parentTransform.inverted());
         }
     }
 
     void remove(KoShape *child) override {
         KIS_SAFE_ASSERT_RECOVER_NOOP(inheritsTransform(child));
         if (inheritsTransform(child)) {
             QTransform parentTransform = q->absoluteTransformation(0);
             child->applyAbsoluteTransformation(parentTransform);
         }
 
         SimpleShapeContainerModel::remove(child);
     }
 
     void shapeHasBeenAddedToHierarchy(KoShape *shape, KoShapeContainer *addedToSubtree) override {
         q->shapeManager()->addShape(shape);
         SimpleShapeContainerModel::shapeHasBeenAddedToHierarchy(shape, addedToSubtree);
     }
 
     void shapeToBeRemovedFromHierarchy(KoShape *shape, KoShapeContainer *removedFromSubtree) override {
         q->shapeManager()->remove(shape);
         SimpleShapeContainerModel::shapeToBeRemovedFromHierarchy(shape, removedFromSubtree);
     }
 
 private:
     KisShapeLayer *q;
 };
 
 
 struct KisShapeLayer::Private
 {
 public:
     Private()
         : canvas(0)
         , controller(0)
         , x(0)
         , y(0)
          {}
 
     KisPaintDeviceSP paintDevice;
     KisShapeLayerCanvas * canvas;
     KoShapeBasedDocumentBase* controller;
     int x;
     int y;
 };
 
 
 KisShapeLayer::KisShapeLayer(KoShapeBasedDocumentBase* controller,
                              KisImageWSP image,
                              const QString &name,
                              quint8 opacity)
     : KisExternalLayer(image, name, opacity),
       KoShapeLayer(new ShapeLayerContainerModel(this)),
       m_d(new Private())
 {
     initShapeLayer(controller);
 }
 
 KisShapeLayer::KisShapeLayer(const KisShapeLayer& rhs)
     : KisShapeLayer(rhs, rhs.m_d->controller)
 {
 }
 
 KisShapeLayer::KisShapeLayer(const KisShapeLayer& _rhs, KoShapeBasedDocumentBase* controller)
         : KisExternalLayer(_rhs)
         , KoShapeLayer(new ShapeLayerContainerModel(this)) //no _rhs here otherwise both layer have the same KoShapeContainerModel
         , m_d(new Private())
 {
     // copy the projection to avoid extra round of updates!
     initShapeLayer(controller, _rhs.m_d->paintDevice);
 
     /**
      * The transformaitons of the added shapes are automatically merged into the transformation
      * of the layer, so we should apply this extra transform separately
      */
     const QTransform thisInvertedTransform = this->absoluteTransformation(0).inverted();
 
     Q_FOREACH (KoShape *shape, _rhs.shapes()) {
         KoShape *clonedShape = shape->cloneShape();
         KIS_SAFE_ASSERT_RECOVER(clonedShape) { continue; }
         clonedShape->setTransformation(shape->absoluteTransformation(0) * thisInvertedTransform);
         addShape(clonedShape);
     }
 }
 
 KisShapeLayer::KisShapeLayer(const KisShapeLayer& _rhs, const KisShapeLayer &_addShapes)
         : KisExternalLayer(_rhs)
         , KoShapeLayer(new ShapeLayerContainerModel(this)) //no _merge here otherwise both layer have the same KoShapeContainerModel
         , m_d(new Private())
 {
     // Make sure our new layer is visible otherwise the shapes cannot be painted.
     setVisible(true);
 
     initShapeLayer(_rhs.m_d->controller);
 
     /**
      * With current implementation this matrix will always be an identity, because
      * we do not copy the transformation from any of the source layers. But we should
      * handle this anyway, to not be caught by this in the future.
      */
     const QTransform thisInvertedTransform = this->absoluteTransformation(0).inverted();
 
     QList<KoShape *> shapesAbove;
     QList<KoShape *> shapesBelow;
 
     // copy in _rhs's shapes
     Q_FOREACH (KoShape *shape, _rhs.shapes()) {
         KoShape *clonedShape = shape->cloneShape();
         KIS_SAFE_ASSERT_RECOVER(clonedShape) { continue; }
         clonedShape->setTransformation(shape->absoluteTransformation(0) * thisInvertedTransform);
         shapesBelow.append(clonedShape);
     }
 
     // copy in _addShapes's shapes
     Q_FOREACH (KoShape *shape, _addShapes.shapes()) {
         KoShape *clonedShape = shape->cloneShape();
         KIS_SAFE_ASSERT_RECOVER(clonedShape) { continue; }
         clonedShape->setTransformation(shape->absoluteTransformation(0) * thisInvertedTransform);
         shapesAbove.append(clonedShape);
     }
 
     QList<KoShapeReorderCommand::IndexedShape> shapes =
         KoShapeReorderCommand::mergeDownShapes(shapesBelow, shapesAbove);
     KoShapeReorderCommand cmd(shapes);
     cmd.redo();
 
     Q_FOREACH (KoShape *shape, shapesBelow + shapesAbove) {
         addShape(shape);
     }
 }
 
 KisShapeLayer::~KisShapeLayer()
 {
     /**
      * Small hack alert: we should avoid updates on shape deletion
      */
     m_d->canvas->prepareForDestroying();
 
     Q_FOREACH (KoShape *shape, shapes()) {
         shape->setParent(0);
         delete shape;
     }
 
     delete m_d->canvas;
     delete m_d;
 }
 
 void KisShapeLayer::initShapeLayer(KoShapeBasedDocumentBase* controller, KisPaintDeviceSP copyFromProjection)
 {
     setSupportsLodMoves(false);
     setShapeId(KIS_SHAPE_LAYER_ID);
 
     KIS_ASSERT_RECOVER_NOOP(this->image());
 
     if (!copyFromProjection) {
         m_d->paintDevice = new KisPaintDevice(image()->colorSpace());
         m_d->paintDevice->setDefaultBounds(new KisDefaultBounds(this->image()));
         m_d->paintDevice->setParentNode(this);
     } else {
         m_d->paintDevice = new KisPaintDevice(*copyFromProjection);
     }
 
     m_d->canvas = new KisShapeLayerCanvas(this, image());
     m_d->canvas->setProjection(m_d->paintDevice);
     m_d->canvas->moveToThread(this->thread());
     m_d->controller = controller;
 
     m_d->canvas->shapeManager()->selection()->disconnect(this);
 
     connect(m_d->canvas->selectedShapesProxy(), SIGNAL(selectionChanged()), this, SIGNAL(selectionChanged()));
     connect(m_d->canvas->selectedShapesProxy(), SIGNAL(currentLayerChanged(const KoShapeLayer*)),
             this, SIGNAL(currentLayerChanged(const KoShapeLayer*)));
 
     connect(this, SIGNAL(sigMoveShapes(const QPointF&)), SLOT(slotMoveShapes(const QPointF&)));
 }
 
 bool KisShapeLayer::allowAsChild(KisNodeSP node) const
 {
     return node->inherits("KisMask");
 }
 
 void KisShapeLayer::setImage(KisImageWSP _image)
 {
     KisLayer::setImage(_image);
     m_d->canvas->setImage(_image);
     m_d->paintDevice->convertTo(_image->colorSpace());
     m_d->paintDevice->setDefaultBounds(new KisDefaultBounds(_image));
 }
 
 KisLayerSP KisShapeLayer::createMergedLayerTemplate(KisLayerSP prevLayer)
 {
     KisShapeLayer *prevShape = dynamic_cast<KisShapeLayer*>(prevLayer.data());
 
     if (prevShape)
         return new KisShapeLayer(*prevShape, *this);
     else
         return KisExternalLayer::createMergedLayerTemplate(prevLayer);
 }
 
 void KisShapeLayer::fillMergedLayerTemplate(KisLayerSP dstLayer, KisLayerSP prevLayer)
 {
     if (!dynamic_cast<KisShapeLayer*>(dstLayer.data())) {
         KisLayer::fillMergedLayerTemplate(dstLayer, prevLayer);
     }
 }
 
 void KisShapeLayer::setParent(KoShapeContainer *parent)
 {
     Q_UNUSED(parent)
     KIS_ASSERT_RECOVER_RETURN(0)
 }
 
 QIcon KisShapeLayer::icon() const
 {
     return KisIconUtils::loadIcon("vectorLayer");
 }
 
 KisPaintDeviceSP KisShapeLayer::original() const
 {
     return m_d->paintDevice;
 }
 
 KisPaintDeviceSP KisShapeLayer::paintDevice() const
 {
     return 0;
 }
 
 qint32 KisShapeLayer::x() const
 {
     return m_d->x;
 }
 
 qint32 KisShapeLayer::y() const
 {
     return m_d->y;
 }
 
 void KisShapeLayer::setX(qint32 x)
 {
     qint32 delta = x - this->x();
     QPointF diff = QPointF(m_d->canvas->viewConverter()->viewToDocumentX(delta), 0);
     emit sigMoveShapes(diff);
 
     // Save new value to satisfy LSP
     m_d->x = x;
 }
 
 void KisShapeLayer::setY(qint32 y)
 {
     qint32 delta = y - this->y();
     QPointF diff = QPointF(0, m_d->canvas->viewConverter()->viewToDocumentY(delta));
     emit sigMoveShapes(diff);
 
     // Save new value to satisfy LSP
     m_d->y = y;
 }
 namespace {
 void filterTransformableShapes(QList<KoShape*> &shapes)
 {
     auto it = shapes.begin();
     while (it != shapes.end()) {
         if (shapes.size() == 1) break;
 
         if ((*it)->inheritsTransformFromAny(shapes)) {
             it = shapes.erase(it);
         } else {
             ++it;
         }
     }
 }
 }
 
 QList<KoShape *> KisShapeLayer::shapesToBeTransformed()
 {
     QList<KoShape*> shapes = shapeManager()->shapes();
 
     // We expect that **all** the shapes inherit the transform from its parent
 
     // SANITY_CHECK: we expect all the shapes inside the
     //               shape layer to inherit transform!
     Q_FOREACH (KoShape *shape, shapes) {
         if (shape->parent()) {
             KIS_SAFE_ASSERT_RECOVER(shape->parent()->inheritsTransform(shape)) {
                 break;
             }
         }
     }
 
     shapes << this;
     filterTransformableShapes(shapes);
     return shapes;
 }
 
 void KisShapeLayer::slotMoveShapes(const QPointF &diff)
 {
     QList<KoShape*> shapes = shapesToBeTransformed();
     if (shapes.isEmpty()) return;
 
     KoShapeMoveCommand cmd(shapes, diff);
     cmd.redo();
 }
 
 bool KisShapeLayer::accept(KisNodeVisitor& visitor)
 {
     return visitor.visit(this);
 }
 
 void KisShapeLayer::accept(KisProcessingVisitor &visitor, KisUndoAdapter *undoAdapter)
 {
     return visitor.visit(this, undoAdapter);
 }
 
 KoShapeManager* KisShapeLayer::shapeManager() const
 {
     return m_d->canvas->shapeManager();
 }
 
 KoViewConverter* KisShapeLayer::converter() const
 {
     return m_d->canvas->viewConverter();
 }
 
 bool KisShapeLayer::visible(bool recursive) const
 {
     return KisExternalLayer::visible(recursive);
 }
 
 void KisShapeLayer::setVisible(bool visible, bool isLoading)
 {
+    const bool oldVisible = this->visible(false);
+
     KoShapeLayer::setVisible(visible);
     KisExternalLayer::setVisible(visible, isLoading);
+
+    if (visible && !oldVisible &&
+        m_d->canvas->hasChangedWhileBeingInvisible()) {
+
+        m_d->canvas->rerenderAfterBeingInvisible();
+    }
 }
 
 void KisShapeLayer::setUserLocked(bool value)
 {
     KoShapeLayer::setGeometryProtected(value);
     KisExternalLayer::setUserLocked(value);
 }
 
 bool KisShapeLayer::isShapeEditable(bool recursive) const
 {
     return KoShapeLayer::isShapeEditable(recursive) && isEditable(true);
 }
 
 // we do not override KoShape::setGeometryProtected() as we consider
 // the user not being able to access the layer shape from Krita UI!
 
 void KisShapeLayer::forceUpdateTimedNode()
 {
     m_d->canvas->forceRepaint();
 }
 
 #include "SvgWriter.h"
 #include "SvgParser.h"
 
 bool KisShapeLayer::saveShapesToStore(KoStore *store, QList<KoShape *> shapes, const QSizeF &sizeInPt)
 {
     if (!store->open("content.svg")) {
         return false;
     }
 
     KoStoreDevice storeDev(store);
     storeDev.open(QIODevice::WriteOnly);
 
     std::sort(shapes.begin(), shapes.end(), KoShape::compareShapeZIndex);
 
     SvgWriter writer(shapes);
     writer.save(storeDev, sizeInPt);
 
     if (!store->close()) {
         return false;
     }
 
     return true;
 }
 
 QList<KoShape *> KisShapeLayer::createShapesFromSvg(QIODevice *device, const QString &baseXmlDir, const QRectF &rectInPixels, qreal resolutionPPI, KoDocumentResourceManager *resourceManager, QSizeF *fragmentSize)
 {
 
     QString errorMsg;
     int errorLine = 0;
     int errorColumn;
 
     KoXmlDocument doc;
     bool ok = doc.setContent(device, false, &errorMsg, &errorLine, &errorColumn);
     if (!ok) {
         errKrita << "Parsing error in " << "contents.svg" << "! Aborting!" << endl
         << " In line: " << errorLine << ", column: " << errorColumn << endl
         << " Error message: " << errorMsg << endl;
         errKrita << i18n("Parsing error in the main document at line %1, column %2\nError message: %3"
                          , errorLine , errorColumn , errorMsg);
     }
 
     SvgParser parser(resourceManager);
     parser.setXmlBaseDir(baseXmlDir);
     parser.setResolution(rectInPixels /* px */, resolutionPPI /* ppi */);
     return parser.parseSvg(doc.documentElement(), fragmentSize);
 }
 
 
 bool KisShapeLayer::saveLayer(KoStore * store) const
 {
     // FIXME: we handle xRes() only!
 
     const QSizeF sizeInPx = image()->bounds().size();
     const QSizeF sizeInPt(sizeInPx.width() / image()->xRes(), sizeInPx.height() / image()->yRes());
 
     return saveShapesToStore(store, this->shapes(), sizeInPt);
 }
 
 bool KisShapeLayer::loadSvg(QIODevice *device, const QString &baseXmlDir)
 {
     QSizeF fragmentSize; // unused!
     KisImageSP image = this->image();
 
     // FIXME: we handle xRes() only!
     KIS_SAFE_ASSERT_RECOVER_NOOP(qFuzzyCompare(image->xRes(), image->yRes()));
     const qreal resolutionPPI = 72.0 * image->xRes();
 
     QList<KoShape*> shapes =
         createShapesFromSvg(device, baseXmlDir,
                             image->bounds(), resolutionPPI,
                             m_d->controller->resourceManager(),
                             &fragmentSize);
 
     Q_FOREACH (KoShape *shape, shapes) {
         addShape(shape);
     }
 
     return true;
 }
 
 bool KisShapeLayer::loadLayer(KoStore* store)
 {
     if (!store) {
         warnKrita << i18n("No store backend");
         return false;
     }
 
     if (store->open("content.svg")) {
         KoStoreDevice storeDev(store);
         storeDev.open(QIODevice::ReadOnly);
 
         loadSvg(&storeDev, "");
 
         store->close();
 
         return true;
     }
 
     KoOdfReadStore odfStore(store);
     QString errorMessage;
 
     odfStore.loadAndParse(errorMessage);
 
     if (!errorMessage.isEmpty()) {
         warnKrita << errorMessage;
         return false;
     }
 
     KoXmlElement contents = odfStore.contentDoc().documentElement();
 
     //    dbgKrita <<"Start loading OASIS document..." << contents.text();
     //    dbgKrita <<"Start loading OASIS contents..." << contents.lastChild().localName();
     //    dbgKrita <<"Start loading OASIS contents..." << contents.lastChild().namespaceURI();
     //    dbgKrita <<"Start loading OASIS contents..." << contents.lastChild().isElement();
 
     KoXmlElement body(KoXml::namedItemNS(contents, KoXmlNS::office, "body"));
 
     if (body.isNull()) {
         //setErrorMessage( i18n( "Invalid OASIS document. No office:body tag found." ) );
         return false;
     }
 
     body = KoXml::namedItemNS(body, KoXmlNS::office, "drawing");
     if (body.isNull()) {
         //setErrorMessage( i18n( "Invalid OASIS document. No office:drawing tag found." ) );
         return false;
     }
 
     KoXmlElement page(KoXml::namedItemNS(body, KoXmlNS::draw, "page"));
     if (page.isNull()) {
         //setErrorMessage( i18n( "Invalid OASIS document. No draw:page tag found." ) );
         return false;
     }
 
     KoXmlElement * master = 0;
     if (odfStore.styles().masterPages().contains("Standard"))
         master = odfStore.styles().masterPages().value("Standard");
     else if (odfStore.styles().masterPages().contains("Default"))
         master = odfStore.styles().masterPages().value("Default");
     else if (! odfStore.styles().masterPages().empty())
         master = odfStore.styles().masterPages().begin().value();
 
     if (master) {
         const KoXmlElement *style = odfStore.styles().findStyle(
                                         master->attributeNS(KoXmlNS::style, "page-layout-name", QString()));
         KoPageLayout pageLayout;
         pageLayout.loadOdf(*style);
         setSize(QSizeF(pageLayout.width, pageLayout.height));
     }
     // We work fine without a master page
 
     KoOdfLoadingContext context(odfStore.styles(), odfStore.store());
     context.setManifestFile(QString("tar:/") + odfStore.store()->currentPath() + "META-INF/manifest.xml");
     KoShapeLoadingContext shapeContext(context, m_d->controller->resourceManager());
 
 
     KoXmlElement layerElement;
     forEachElement(layerElement, context.stylesReader().layerSet()) {
         // FIXME: investigate what is this
         //        KoShapeLayer * l = new KoShapeLayer();
         if (!loadOdf(layerElement, shapeContext)) {
             dbgKrita << "Could not load vector layer!";
             return false;
         }
     }
 
     KoXmlElement child;
     forEachElement(child, page) {
         KoShape * shape = KoShapeRegistry::instance()->createShapeFromOdf(child, shapeContext);
         if (shape) {
             addShape(shape);
         }
     }
 
     return true;
 
 }
 
 void KisShapeLayer::resetCache()
 {
-    m_d->paintDevice->clear();
-
-    QList<KoShape*> shapes = m_d->canvas->shapeManager()->shapes();
-    Q_FOREACH (const KoShape* shape, shapes) {
-        shape->update();
-    }
+    m_d->canvas->resetCache();
 }
 
 KUndo2Command* KisShapeLayer::crop(const QRect & rect)
 {
     QPoint oldPos(x(), y());
     QPoint newPos = oldPos - rect.topLeft();
 
     return new KisNodeMoveCommand2(this, oldPos, newPos);
 }
 
 KUndo2Command* KisShapeLayer::transform(const QTransform &transform) {
     QList<KoShape*> shapes = shapesToBeTransformed();
     if (shapes.isEmpty()) return 0;
 
     KisImageViewConverter *converter = dynamic_cast<KisImageViewConverter*>(this->converter());
     QTransform realTransform = converter->documentToView() *
         transform * converter->viewToDocument();
 
     QList<QTransform> oldTransformations;
     QList<QTransform> newTransformations;
 
     QList<KoShapeShadow*> newShadows;
     const qreal transformBaseScale = KoUnit::approxTransformScale(transform);
 
     Q_FOREACH (const KoShape* shape, shapes) {
         QTransform oldTransform = shape->transformation();
         oldTransformations.append(oldTransform);
 
         QTransform globalTransform = shape->absoluteTransformation(0);
         QTransform localTransform = globalTransform * realTransform * globalTransform.inverted();
         newTransformations.append(localTransform * oldTransform);
 
         KoShapeShadow *shadow = 0;
 
         if (shape->shadow()) {
             shadow = new KoShapeShadow(*shape->shadow());
             shadow->setOffset(transformBaseScale * shadow->offset());
             shadow->setBlur(transformBaseScale * shadow->blur());
         }
 
         newShadows.append(shadow);
 
     }
 
     KUndo2Command *parentCommand = new KUndo2Command();
     new KoShapeTransformCommand(shapes,
                                 oldTransformations,
                                 newTransformations,
                                 parentCommand);
 
     new KoShapeShadowCommand(shapes,
                              newShadows,
                              parentCommand);
 
     return parentCommand;
 }
 
diff --git a/libs/ui/flake/kis_shape_layer_canvas.cpp b/libs/ui/flake/kis_shape_layer_canvas.cpp
index 3a70916e77..9778713a45 100644
--- a/libs/ui/flake/kis_shape_layer_canvas.cpp
+++ b/libs/ui/flake/kis_shape_layer_canvas.cpp
@@ -1,311 +1,336 @@
 /*
  *  Copyright (c) 2007 Boudewijn Rempt <boud@valdyas.org>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
 #include "kis_shape_layer_canvas.h"
 
 #include <QPainter>
 #include <QMutexLocker>
 
 #include <KoShapeManager.h>
 #include <KoSelectedShapesProxySimple.h>
 #include <KoViewConverter.h>
 #include <KoColorSpace.h>
 
 #include <kis_paint_device.h>
 #include <kis_image.h>
 #include <kis_layer.h>
 #include <kis_painter.h>
 #include <flake/kis_shape_layer.h>
 #include <KoCompositeOpRegistry.h>
 #include <KoSelection.h>
 #include <KoUnit.h>
 #include "kis_image_view_converter.h"
 
 #include <kis_debug.h>
 
 #include <QThread>
 #include <QApplication>
 
 #include <kis_spontaneous_job.h>
 #include "kis_image.h"
 #include "kis_global.h"
 
 //#define DEBUG_REPAINT
 
 KisShapeLayerCanvas::KisShapeLayerCanvas(KisShapeLayer *parent, KisImageWSP image)
         : KoCanvasBase(0)
         , m_isDestroying(false)
         , m_viewConverter(new KisImageViewConverter(image))
         , m_shapeManager(new KoShapeManager(this))
         , m_selectedShapesProxy(new KoSelectedShapesProxySimple(m_shapeManager.data()))
         , m_projection(0)
         , m_parentLayer(parent)
         , m_asyncUpdateSignalCompressor(100, KisSignalCompressor::FIRST_INACTIVE)
         , m_image(image)
 {
     /**
      * The layour should also add itself to its own shape manager, so that the canvas
      * would track its changes/transformations
      */
     m_shapeManager->addShape(parent, KoShapeManager::AddWithoutRepaint);
     m_shapeManager->selection()->setActiveLayer(parent);
 
     connect(this, SIGNAL(forwardRepaint()), SLOT(repaint()), Qt::QueuedConnection);
     connect(&m_asyncUpdateSignalCompressor, SIGNAL(timeout()), SLOT(slotStartAsyncRepaint()));
 
     connect(m_image, SIGNAL(sigSizeChanged(const QPointF &, const QPointF &)), SLOT(slotImageSizeChanged()));
     m_cachedImageRect = m_image->bounds();
 }
 
 KisShapeLayerCanvas::~KisShapeLayerCanvas()
 {
     m_shapeManager->remove(m_parentLayer);
 }
 
 void KisShapeLayerCanvas::setImage(KisImageWSP image)
 {
     m_viewConverter->setImage(image);
 }
 
 void KisShapeLayerCanvas::prepareForDestroying()
 {
     m_isDestroying = true;
 }
 
 void KisShapeLayerCanvas::gridSize(QPointF *offset, QSizeF *spacing) const
 {
     Q_ASSERT(false); // This should never be called as this canvas should have no tools.
     Q_UNUSED(offset);
     Q_UNUSED(spacing);
 }
 
 bool KisShapeLayerCanvas::snapToGrid() const
 {
     Q_ASSERT(false); // This should never be called as this canvas should have no tools.
     return false;
 }
 
 void KisShapeLayerCanvas::addCommand(KUndo2Command *)
 {
     Q_ASSERT(false); // This should never be called as this canvas should have no tools.
 }
 
 KoShapeManager *KisShapeLayerCanvas::shapeManager() const
 {
     return m_shapeManager.data();
 }
 
 KoSelectedShapesProxy *KisShapeLayerCanvas::selectedShapesProxy() const
 {
     return m_selectedShapesProxy.data();
 }
 
 #ifdef DEBUG_REPAINT
 # include <stdlib.h>
 #endif
 
 
 class KisRepaintShapeLayerLayerJob : public KisSpontaneousJob
 {
 public:
     KisRepaintShapeLayerLayerJob(KisShapeLayerSP layer, KisShapeLayerCanvas *canvas)
         : m_layer(layer),
           m_canvas(canvas)
     {
     }
 
     bool overrides(const KisSpontaneousJob *_otherJob) override {
         const KisRepaintShapeLayerLayerJob *otherJob =
             dynamic_cast<const KisRepaintShapeLayerLayerJob*>(_otherJob);
 
         return otherJob && otherJob->m_canvas == m_canvas;
     }
 
     void run() override {
         m_canvas->repaint();
     }
 
     int levelOfDetail() const override {
         return 0;
     }
 
 private:
 
     // we store a pointer to the layer just
     // to keep the lifetime of the canvas!
     KisShapeLayerSP m_layer;
 
     KisShapeLayerCanvas *m_canvas;
 };
 
 
 void KisShapeLayerCanvas::updateCanvas(const QVector<QRectF> &region)
 {
     if (!m_parentLayer->image() || m_isDestroying) {
         return;
     }
 
     {
         QMutexLocker locker(&m_dirtyRegionMutex);
         Q_FOREACH (const QRectF &rc, region) {
             // grow for antialiasing
             const QRect imageRect = kisGrowRect(m_viewConverter->documentToView(rc).toAlignedRect(), 2);
             m_dirtyRegion += imageRect;
         }
     }
 
     /**
      * HACK ALERT!
      *
      * The shapes may be accessed from both, GUI and worker threads! And we have no real
      * guard against this until the vector tools will be ported to the strokes framework.
      *
      * Here we just avoid the most obvious conflict of threads:
      *
      * 1) If the layer if modified by a non-gui (worker) thread, use a spontaneous jobs
      *    to rerender the canvas. The job will be executed (almost) exclusively and it is
      *    the responsibility of the worker thread to add a barrier to wait until this job is
      *    completed, and not try to access the shapes concurrently.
      *
      * 2) If the layer is modified by a gui thread, it means that we are being accessed by
      *    a legacy vector tool. It this case just emit a queued signal to make sure the updates
      *    are compressed a little bit (TODO: add a compressor?)
      */
 
     if (qApp->thread() == QThread::currentThread()) {
         emit forwardRepaint();
     } else {
         m_asyncUpdateSignalCompressor.start();
         m_hasUpdateInCompressor = true;
     }
 }
 
 
 void KisShapeLayerCanvas::updateCanvas(const QRectF& rc)
 {
     updateCanvas(QVector<QRectF>({rc}));
 }
 
 void KisShapeLayerCanvas::slotStartAsyncRepaint()
 {
     m_hasUpdateInCompressor = false;
     m_image->addSpontaneousJob(new KisRepaintShapeLayerLayerJob(m_parentLayer, this));
 }
 
 void KisShapeLayerCanvas::slotImageSizeChanged()
 {
     QRegion dirtyCacheRegion;
     dirtyCacheRegion += m_image->bounds();
     dirtyCacheRegion += m_cachedImageRect;
     dirtyCacheRegion -= m_image->bounds() & m_cachedImageRect;
 
     QVector<QRectF> dirtyRects;
     Q_FOREACH (const QRect &rc, dirtyCacheRegion.rects()) {
         dirtyRects.append(m_viewConverter->viewToDocument(rc));
     }
     updateCanvas(dirtyRects);
 
     m_cachedImageRect = m_image->bounds();
 }
 
 void KisShapeLayerCanvas::repaint()
 {
 
     QRect r;
 
     {
         QMutexLocker locker(&m_dirtyRegionMutex);
         r = m_dirtyRegion.boundingRect();
         m_dirtyRegion = QRegion();
     }
 
     if (r.isEmpty()) return;
 
     // Crop the update rect by the image bounds. We keep the cache consistent
     // by tracking the size of the image in slotImageSizeChanged()
     r = r.intersected(m_parentLayer->image()->bounds());
 
     QImage image(r.width(), r.height(), QImage::Format_ARGB32);
     image.fill(0);
     QPainter p(&image);
 
     p.setRenderHint(QPainter::Antialiasing);
     p.setRenderHint(QPainter::TextAntialiasing);
     p.translate(-r.x(), -r.y());
     p.setClipRect(r);
 #ifdef DEBUG_REPAINT
     QColor color = QColor(random() % 255, random() % 255, random() % 255);
     p.fillRect(r, color);
 #endif
 
     m_shapeManager->paint(p, *m_viewConverter, false);
     p.end();
 
     KisPaintDeviceSP dev = new KisPaintDevice(m_projection->colorSpace());
     dev->convertFromQImage(image, 0);
 
     KisPainter::copyAreaOptimized(r.topLeft(), dev, m_projection, QRect(QPoint(), r.size()));
 
     m_parentLayer->setDirty(r);
+
+    m_hasChangedWhileBeingInvisible |= !m_parentLayer->visible(true);
 }
 
 KoToolProxy * KisShapeLayerCanvas::toolProxy() const
 {
 //     Q_ASSERT(false); // This should never be called as this canvas should have no tools.
     return 0;
 }
 
 KoViewConverter* KisShapeLayerCanvas::viewConverter() const
 {
     return m_viewConverter.data();
 }
 
 QWidget* KisShapeLayerCanvas::canvasWidget()
 {
     return 0;
 }
 
 const QWidget* KisShapeLayerCanvas::canvasWidget() const
 {
     return 0;
 }
 
 KoUnit KisShapeLayerCanvas::unit() const
 {
     Q_ASSERT(false); // This should never be called as this canvas should have no tools.
     return KoUnit(KoUnit::Point);
 }
 
 
 void KisShapeLayerCanvas::forceRepaint()
 {
     /**
      * WARNING! Although forceRepaint() may be called from different threads, it is
      * not entirely safe. If the user plays with shapes at the same time (vector tools are
      * not ported to strokes yet), the shapes my be accessed from two different places at
      * the same time, which will cause a crash.
      *
      * The only real solution to this is to port vector tools to strokes framework.
      */
 
     if (m_hasUpdateInCompressor) {
         m_asyncUpdateSignalCompressor.stop();
         slotStartAsyncRepaint();
     }
 }
 
+void KisShapeLayerCanvas::resetCache()
+{
+    m_projection->clear();
+
+    QList<KoShape*> shapes = m_shapeManager->shapes();
+    Q_FOREACH (const KoShape* shape, shapes) {
+        shape->update();
+    }
+}
+
+bool KisShapeLayerCanvas::hasChangedWhileBeingInvisible()
+{
+    return m_hasChangedWhileBeingInvisible;
+}
+
+void KisShapeLayerCanvas::rerenderAfterBeingInvisible()
+{
+    KIS_SAFE_ASSERT_RECOVER_RETURN(m_parentLayer->visible(true))
+
+    m_hasChangedWhileBeingInvisible = false;
+    resetCache();
+}
+
diff --git a/libs/ui/flake/kis_shape_layer_canvas.h b/libs/ui/flake/kis_shape_layer_canvas.h
index 1e44e9c2f2..a57771fad9 100644
--- a/libs/ui/flake/kis_shape_layer_canvas.h
+++ b/libs/ui/flake/kis_shape_layer_canvas.h
@@ -1,104 +1,110 @@
 /*
  *  Copyright (c) 2007 Boudewijn Rempt <boud@valdyas.org>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 #ifndef KIS_SHAPE_LAYER_CANVAS_H
 #define KIS_SHAPE_LAYER_CANVAS_H
 
 #include <QMutex>
 #include <QRegion>
 #include <KoCanvasBase.h>
 
 #include <kis_types.h>
 #include "kis_thread_safe_signal_compressor.h"
 
 class KoShapeManager;
 class KoToolProxy;
 class KoViewConverter;
 class KUndo2Command;
 class QWidget;
 class KoUnit;
 class KisImageViewConverter;
 
 /**
  * KisShapeLayerCanvas is a special canvas implementation that Krita
  * uses for non-krita shapes to request updates on.
  *
  * Do NOT give this canvas to tools or to the KoCanvasController, it's
  * not made for that.
  */
 class KisShapeLayerCanvas : public KoCanvasBase
 {
     Q_OBJECT
 public:
 
     KisShapeLayerCanvas(KisShapeLayer *parent, KisImageWSP image);
     ~KisShapeLayerCanvas() override;
 
     /// This canvas won't render onto a widget, but a projection
     void setProjection(KisPaintDeviceSP projection) {
         m_projection = projection;
     }
 
     void setImage(KisImageWSP image);
 
     void prepareForDestroying();
     void gridSize(QPointF *offset, QSizeF *spacing) const override;
     bool snapToGrid() const override;
     void addCommand(KUndo2Command *command) override;
     KoShapeManager *shapeManager() const override;
     KoSelectedShapesProxy *selectedShapesProxy() const override;
     void updateCanvas(const QRectF& rc) override;
     KoToolProxy * toolProxy() const override;
     KoViewConverter* viewConverter() const override;
     QWidget* canvasWidget() override;
     const QWidget* canvasWidget() const override;
     KoUnit unit() const override;
     void updateInputMethodInfo() override {}
     void setCursor(const QCursor &) override {}
 
     void updateCanvas(const QVector<QRectF> &region);
 
     void forceRepaint();
 
+    void resetCache();
+    bool hasChangedWhileBeingInvisible();
+    void rerenderAfterBeingInvisible();
+
 private Q_SLOTS:
     friend class KisRepaintShapeLayerLayerJob;
     void repaint();
     void slotStartAsyncRepaint();
     void slotImageSizeChanged();
 Q_SIGNALS:
     void forwardRepaint();
 private:
 
     bool m_isDestroying;
     QScopedPointer<KisImageViewConverter> m_viewConverter;
     QScopedPointer<KoShapeManager> m_shapeManager;
     QScopedPointer<KoSelectedShapesProxy> m_selectedShapesProxy;
     KisPaintDeviceSP m_projection;
     KisShapeLayer *m_parentLayer;
 
     KisThreadSafeSignalCompressor m_asyncUpdateSignalCompressor;
     volatile bool m_hasUpdateInCompressor = false;
 
+    bool m_hasChangedWhileBeingInvisible = false;
+
     QRegion m_dirtyRegion;
     QMutex m_dirtyRegionMutex;
 
     QRect m_cachedImageRect;
 
     KisImageWSP m_image;
 };
 
 #endif