Basic model/view action works

15 files changed, 438 insertions, 132 deletions

diff --git a/numberator.cpp b/numberator.cpp
index 912c5e3..29c0d6b 100644
--- a/numberator.cpp
+++ b/numberator.cpp
@@ -29,6 +29,8 @@ Numberator::Numberator(QWidget *parent)
     connect(ui->actionReload_Image, &QAction::triggered,

             &proj, &SQLiteSaveFile::reloadImageFromDisk);

 

+    ui->graphicsView->setProject(&proj);

+

     tagsDockUi->tagList->setModel(&tagListModel);

     tagsDockUi->propertyTable->setModel(&tagPropTableModel);

 

@@ -78,11 +80,15 @@ Numberator::Numberator(QWidget *parent)
     });

     connect(ui->actionAbout, &QAction::triggered, &aboutDialog, &AboutDialog::open);

 

-    connect(tagsDockUi->tagList->selectionModel(), &QItemSelectionModel::currentChanged,

-            [=](const QModelIndex &current, const QModelIndex &previous) {

-        Q_UNUSED(previous);

-        tagPropTableModel.showTag(tagListModel.getTag(current));

+    connect(tagsDockUi->tagList->selectionModel(), &QItemSelectionModel::selectionChanged,

+            [=](const QItemSelection &selected, const QItemSelection &deselected) {

+        Q_UNUSED(deselected);

+        tagPropTableModel.showTag(tagListModel.getTag(selected.indexes().first()));

     });

+

+    connect(ui->actionZoom_to_fit, &QAction::triggered, ui->graphicsView, &TagView::zoomToFit);

+    connect(ui->actionZoom_in, &QAction::triggered, ui->graphicsView, &TagView::zoomIn);

+    connect(ui->actionZoom_out, &QAction::triggered, ui->graphicsView, &TagView::zoomOut);

 }

 

 Numberator::~Numberator()

diff --git a/numberator.h b/numberator.h
index bf661db..4192196 100644
--- a/numberator.h
+++ b/numberator.h
@@ -5,6 +5,7 @@
 #include "sqlitebackend.h"

 #include "taglistmodel.h"

 #include "tagproptablemodel.h"

+#include "tagview.h"

 

 #include <QFileDialog>

 #include <QMainWindow>

@@ -41,5 +42,6 @@ private:
     SQLiteSaveFile proj;

     TagListModel tagListModel;

     TagPropTableModel tagPropTableModel;

+    TagView m_tagView;

 };

 #endif // NUMBERATOR_H

diff --git a/numberator.ui b/numberator.ui
index 8bf3371..70b9e14 100644
--- a/numberator.ui
+++ b/numberator.ui
@@ -16,7 +16,7 @@
   <widget class="QWidget" name="centralwidget">

    <layout class="QVBoxLayout" name="verticalLayout">

     <item>

-     <widget class="QGraphicsView" name="graphicsView"/>

+     <widget class="TagView" name="graphicsView"/>

     </item>

    </layout>

   </widget>

@@ -69,6 +69,9 @@
     <property name="title">

      <string>View</string>

     </property>

+    <addaction name="actionZoom_to_fit"/>

+    <addaction name="actionZoom_in"/>

+    <addaction name="actionZoom_out"/>

    </widget>

    <addaction name="menuFile"/>

    <addaction name="menuEdit"/>

@@ -85,11 +88,17 @@
    <property name="text">

     <string>Undo</string>

    </property>

+   <property name="shortcut">

+    <string>Ctrl+Z</string>

+   </property>

   </action>

   <action name="actionRedo">

    <property name="text">

     <string>Redo</string>

    </property>

+   <property name="shortcut">

+    <string>Ctrl+R</string>

+   </property>

   </action>

   <action name="actionCopy">

    <property name="text">

@@ -100,46 +109,73 @@
    <property name="text">

     <string>Cut</string>

    </property>

+   <property name="shortcut">

+    <string>Ctrl+X</string>

+   </property>

   </action>

   <action name="actionPaste">

    <property name="text">

     <string>Paste</string>

    </property>

+   <property name="shortcut">

+    <string>Ctrl+V</string>

+   </property>

   </action>

   <action name="actionNew_Tag">

    <property name="text">

     <string>New Tag</string>

    </property>

+   <property name="shortcut">

+    <string>Ctrl+A</string>

+   </property>

   </action>

   <action name="actionNew_Project">

    <property name="text">

     <string>New Project</string>

    </property>

+   <property name="shortcut">

+    <string>Ctrl+N</string>

+   </property>

   </action>

   <action name="actionOpen_Project">

    <property name="text">

     <string>Open Project</string>

    </property>

+   <property name="shortcut">

+    <string>Ctrl+O</string>

+   </property>

   </action>

   <action name="actionImport_Image">

    <property name="text">

     <string>Import Image</string>

    </property>

+   <property name="shortcut">

+    <string>Ctrl+I</string>

+   </property>

   </action>

   <action name="actionReload_Image">

    <property name="text">

     <string>Reload Image</string>

    </property>

+   <property name="shortcut">

+    <string>F5</string>

+   </property>

   </action>

   <action name="actionSave_Project">

    <property name="text">

-    <string>Save Project</string>

+    <string>Save Project as...</string>

+   </property>

+   <property name="shortcut">

+    <string>Ctrl+Shift+S</string>

    </property>

   </action>

   <action name="actionExport_PDF">

    <property name="text">

     <string>Export PDF</string>

    </property>

+   <property name="shortcut">

+    <string>Ctrl+E</string>

+   </property>

   </action>

   <action name="actionExport_PNG">

    <property name="text">

@@ -150,8 +186,36 @@
    <property name="text">

     <string>Exit</string>

    </property>

+   <property name="shortcut">

+    <string>Ctrl+Q</string>

+   </property>

+  </action>

+  <action name="actionZoom_to_fit">

+   <property name="text">

+    <string>Zoom to fit</string>

+   </property>

+   <property name="shortcut">

+    <string>Ctrl+0</string>

+   </property>

+  </action>

+  <action name="actionZoom_in">

+   <property name="text">

+    <string>Zoom in</string>

+   </property>

+  </action>

+  <action name="actionZoom_out">

+   <property name="text">

+    <string>Zoom out</string>

+   </property>

   </action>

  </widget>

+ <customwidgets>

+  <customwidget>

+   <class>TagView</class>

+   <extends>QGraphicsView</extends>

+   <header>tagview.h</header>

+  </customwidget>

+ </customwidgets>

  <resources/>

  <connections/>

 </ui>

diff --git a/sqlitebackend.cpp b/sqlitebackend.cpp
index 89b7b07..4a9f8b9 100644
--- a/sqlitebackend.cpp
+++ b/sqlitebackend.cpp
@@ -14,8 +14,8 @@ SQLiteSaveFile::SQLiteSaveFile(QObject *parent) :
 

 bool SQLiteSaveFile::open(const QString &filename)

 {

-    qDebug() << "open";

-    {

+    auto dbg = qDebug() << "open";

+    { /* Emit signals only after unlocking mutex to allow accesses by receivers */

         QMutexLocker l(&m_dbMut);

         QFile f(filename);

         if (!f.exists()) {

@@ -44,15 +44,16 @@ bool SQLiteSaveFile::open(const QString &filename)
         m_dirty = false;

         m_open = true;

         m_image = q.value(0).toByteArray();

+        dbg << QString("Loaded %1 byte image").arg(m_image.size());

     }

-    fileReload(); /* Call after unlocking mutex to allow accesses by receivers */

+    fileReload();

     return true;

 }

 

 bool SQLiteSaveFile::clearNew()

 {

     qDebug() << "clearNew";

-    {

+    { /* Emit signals only after unlocking mutex to allow accesses by receivers */

         QMutexLocker l(&m_dbMut);

 

         QSqlDatabase new_db(QSqlDatabase::addDatabase("QSQLITE", QUuid::createUuid().toString()));

@@ -148,7 +149,7 @@ bool SQLiteSaveFile::saveAs(const QString &filename)
 

 QList<Tag> SQLiteSaveFile::getAllTags()

 {

-    qDebug() << "getAllTags";

+    auto dbg = qDebug() << "getAllTags()";

     QMutexLocker l(&m_dbMut);

     resetError();

     QList<Tag> rv;

@@ -170,56 +171,134 @@ QList<Tag> SQLiteSaveFile::getAllTags()
     if (!setDatabaseError(q))

         return QList<Tag>();

 

+    dbg << QString("%1 tags").arg(rv.size());

     return rv;

 }

 

 bool SQLiteSaveFile::updateTag(Tag tag)

 {

-    QMutexLocker l(&m_dbMut);

-    if (!runSql("UPDATE tags SET name=?, anchor_x=?, anchor_y=?, meta=? WHERE id=?", {

-               tag.name, tag.anchor.x(), tag.anchor.y(), QJsonDocument::fromVariant(tag.metadata).toJson(), tag.id

-           }))

-        return false;

+    auto dbg = qDebug() << "updating tag" << tag.id << tag.name;

+    {

+        QMutexLocker l(&m_dbMut);

+        QSqlQuery q(m_db);

+        q.prepare("SELECT 1 FROM tags WHERE id=? AND name=?");

+        q.addBindValue(tag.id);

+        q.addBindValue(tag.name);

+        if (!q.exec()) {

+            setDatabaseError(q);

+            return false;

+        }

+        bool nameChanged = !q.next();

+        if (!setDatabaseError(q))

+                return false;

 

-    m_dirty = true;

+        if (nameChanged)

+            setMetaLocked("lastTagName", tag.name);

+

+        if (!runSql("UPDATE tags SET name=?, anchor_x=?, anchor_y=?, meta=? WHERE id=?", {

+                   tag.name, tag.anchor.x(), tag.anchor.y(), QJsonDocument::fromVariant(tag.metadata).toJson(), tag.id

+               })) {

+            return false;

+        }

+

+        m_dirty = true;

+    }

+    dbg << "calling handlers";

     tagChange(TagChange::CHANGED, tag);

     return true;

 }

 

 bool SQLiteSaveFile::deleteTag(Tag tag)

 {

-    QMutexLocker l(&m_dbMut);

-    if (!runSql("DELETE FROM tags WHERE id=?", {tag.id}))

-        return false;

+    {

+        QMutexLocker l(&m_dbMut);

+        if (!runSql("DELETE FROM tags WHERE id=?", {tag.id}))

+            return false;

 

-    m_dirty = true;

+        m_dirty = true;

+    }

     tagChange(TagChange::DELETED, tag);

     return true;

 }

 

 bool SQLiteSaveFile::createTag(Tag tag)

 {

-    qDebug() << "createTag";

+    QSqlQuery q(m_db);

+    auto dbg = qDebug() << "createTag";

+    {

+        QMutexLocker l(&m_dbMut);

+        resetError();

+        if (!runSql("INSERT INTO tags(name, anchor_x, anchor_y, meta) VALUES (?, ?, ?, ?)", {

+                   tag.name,

+                   tag.anchor.x(),

+                   tag.anchor.y(),

+                   QJsonDocument::fromVariant(tag.metadata).toJson()

+               })) {

+            return false;

+        }

+        m_dirty = true;

+    }

+    auto id = q.lastInsertId().toLongLong();

+    dbg << "id" << id;

+    tagChange(TagChange::CREATED, Tag(id, tag));

+    return true;

+}

+

+QString SQLiteSaveFile::getNextAutoTagName()

+{

+    QVariant lookupResult = getMeta("lastTagName");

+    QString lastTagName = "U0";

+    if (lookupResult.isValid() && !lookupResult.toString().isNull())

+        lastTagName = lookupResult.toString();

+    QString newName = "U1";

+

+    QRegularExpression name_re("^(.*?)(\\d+)$");

+    auto res = name_re.match(lastTagName);

+    if (res.hasMatch()) {

+        bool ok = false;

+        int numericSuffix = res.captured(2).toInt(&ok);

+        QString stringPrefix = res.captured(1);

+        qDebug() << "Name has match" << stringPrefix << numericSuffix;

+

+        if (ok) {

+            do {

+                numericSuffix ++;

+                newName = QString("%1%2").arg(stringPrefix).arg(numericSuffix);

+            } while (numericSuffix<10000 && !tagNameIsFree(newName));

+        }

+    }

+    return newName;

+}

+

+bool SQLiteSaveFile::createTagAt(const QPointF &anchor)

+{

+    QString newName = getNextAutoTagName();

+    if (!setMeta("lastTagName", newName))

+        return false;

+    return createTag(Tag(newName, anchor));

+}

+

+bool SQLiteSaveFile::tagNameIsFree(const QString &name)

+{

     QMutexLocker l(&m_dbMut);

-    resetError();

     QSqlQuery q(m_db);

-    q.prepare("INSERT INTO tags(name, anchor_x, anchor_y, meta) VALUES (?, ?, ?, ?)");

-    q.addBindValue(tag.name);

-    q.addBindValue(tag.anchor.x());

-    q.addBindValue(tag.anchor.y());

-    q.addBindValue(QJsonDocument::fromVariant(tag.metadata).toJson());

+    q.prepare("SELECT name FROM tags WHERE name=?");

+    q.addBindValue(name);

+    if (!q.exec()) {

+        setDatabaseError(q);

+        return true;

+    }

 

-    if (!setDatabaseError(q))

+    if (q.next())

         return false;

 

-    Tag created_tag(q.lastInsertId().toLongLong(), tag);

-    m_dirty = true;

-    tagChange(TagChange::CREATED, created_tag);

+    setDatabaseError(q);

     return true;

 }

 

 bool SQLiteSaveFile::setMetaLocked(const QString &key, const QVariant &value)

 {

+    qDebug() << QString("setMeta: %1=%2").arg(key).arg(value.toString());

     return runSql("INSERT OR REPLACE INTO metadata(key, value) VALUES (?, ?)", {key, value});

 }

 

@@ -232,15 +311,15 @@ bool SQLiteSaveFile::setMetaLocked(std::initializer_list<QPair<QString, QVariant
     return true;

 }

 

-bool SQLiteSaveFile::setMeta(const QString &key, const QVariant &value) {

+bool SQLiteSaveFile::setMeta(const QString &key, const QVariant &value, bool setDirty) {

     QMutexLocker l(&m_dbMut);

-    m_dirty = true;

+    m_dirty = m_dirty || setDirty;

     return setMetaLocked(key, value);

 }

 

-bool SQLiteSaveFile::setMeta(std::initializer_list<QPair<QString, QVariant>> metas) {

+bool SQLiteSaveFile::setMeta(std::initializer_list<QPair<QString, QVariant>> metas, bool setDirty) {

     QMutexLocker l(&m_dbMut);

-    m_dirty = true;

+    m_dirty = m_dirty || setDirty;

     return setMetaLocked(metas);

 }

 

@@ -251,7 +330,6 @@ const QVariant SQLiteSaveFile::getMeta(const QString &key) const {
 

 const QVariant SQLiteSaveFile::getMetaLocked(const QString &key) const

 {

-    qDebug() << "getMeta " << key;

     resetError();

     QSqlQuery q(m_db);

     q.prepare("SELECT value FROM metadata WHERE key=?");

@@ -267,6 +345,7 @@ const QVariant SQLiteSaveFile::getMetaLocked(const QString &key) const
         return QVariant();

     }

 

+    qDebug() << QString("getMeta: %1=%2").arg(key).arg(q.value(0).toString());

     return q.value(0);

 }

 

@@ -288,29 +367,35 @@ bool SQLiteSaveFile::runSql(QString query, std::initializer_list<QVariant> bindi
 

 bool SQLiteSaveFile::loadImageFromDisk(const QString &filename)

 {

-    QMutexLocker l(&m_dbMut);

-    QFile f(filename);

-    resetError();

-

-    if (!f.open(QIODevice::ReadOnly)) {

-        setError(ImageOpenError, QString("Failed to open image: %1").arg(f.errorString()));

-        return false;

-    }

-

-    m_image = f.readAll();

-    if (f.error() != QFileDevice::NoError) {

-        setError(ImageReadError, QString("Failed to read image: %1").arg(f.errorString()));

-        return false;

+    {

+        QMutexLocker l(&m_dbMut);

+        QFile f(filename);

+        resetError();

+    

+        if (!f.open(QIODevice::ReadOnly)) {

+            setError(ImageOpenError, QString("Failed to open image: %1").arg(f.errorString()));

+            return false;

+        }

+    

+        m_image = f.readAll();

+        if (f.error() != QFileDevice::NoError) {

+            setError(ImageReadError, QString("Failed to read image: %1").arg(f.errorString()));

+            return false;

+        }

+    

+        if (!setMetaLocked({

+                     {"imagePathOriginal", f.fileName()},

+                     {"imagePathAbsolute", QFileInfo(f).absoluteFilePath()},

+                     {"imageLoadedTime", QDateTime::currentDateTimeUtc().toMSecsSinceEpoch()}}))

+            return false;

+    

+        m_dirty = true;

+        if (!runSql("INSERT OR REPLACE INTO blobs(name, data) VALUES ('image', ?)", {m_image}))

+            return false;

     }

-

-    if (!setMetaLocked({

-                 {"imagePathOriginal", f.fileName()},

-                 {"imagePathAbsolute", QFileInfo(f).absoluteFilePath()},

-                 {"imageLoadedTime", QDateTime::currentDateTimeUtc().toMSecsSinceEpoch()}}))

-        return false;

-

-    m_dirty = true;

-    return runSql("INSERT OR REPLACE INTO blobs(name, data) VALUES ('image', ?)", {m_image});

+    /* Emit signal with mutex unlocked */

+    imageLoaded(m_image);

+    return true;

 }

 

 bool SQLiteSaveFile::reloadImageFromDisk()

@@ -344,6 +429,15 @@ Tag::Tag(long long id, const Tag &other)
 {

 }

 

+Tag::Tag(QString name, const QPointF &anchor, const QVariantMap metadata)

+    : id(-1)

+    , name(name)

+    , anchor(anchor)

+    , metadata(metadata)

+    , valid(false)

+{

+}

+

 bool SQLiteSaveFile::setDatabaseError(const QSqlQuery &q) const

 {

     if (!q.lastError().isValid())

diff --git a/sqlitebackend.h b/sqlitebackend.h
index 8bfce00..0e7d339 100644
--- a/sqlitebackend.h
+++ b/sqlitebackend.h
@@ -19,6 +19,7 @@ public:
     Tag() : valid(false) {}

     Tag(long long int id, QString name, qreal anchor_x, qreal anchor_y, QByteArray metadata);

     Tag(long long int id, const Tag &other);

+    Tag(QString name, const QPointF &anchor, const QVariantMap metadata=QVariantMap());

 

     bool isValid() { return valid; }

 

@@ -44,13 +45,17 @@ public:
     bool updateTag(Tag tag);

     bool deleteTag(Tag tag);

     bool createTag(Tag tag);

+    bool createTagAt(const QPointF &anchor);

+    QString getNextAutoTagName();

+

+    bool tagNameIsFree(const QString &name);

 

     bool isMemory() { return m_memory; } /* backend db points to temporary memory db */

     bool isDirty() { return m_dirty; } /* backend db was changed since opening */

     bool isOpen() { return m_open; } /* backend db is open */

 

-    bool setMeta(const QString &key, const QVariant &value);

-    bool setMeta(std::initializer_list<QPair<QString, QVariant>> metas);

+    bool setMeta(const QString &key, const QVariant &value, bool setDirty=false);

+    bool setMeta(std::initializer_list<QPair<QString, QVariant>> metas, bool setDirty=false);

     const QVariant getMeta(const QString &key) const;

 

     const QString &errorString() const { return m_lastErrorString; }

@@ -87,6 +92,7 @@ signals:
     void tagChange(TagChange change, const Tag &tag);

     void fileReload();

     void fileIOError(Error e, QString errorName, QString description) const;

+    void imageLoaded(const QByteArray &image);

 

 private:

     bool connect();

diff --git a/tagitem.cpp b/tagitem.cpp
index d251428..e493b81 100644
--- a/tagitem.cpp
+++ b/tagitem.cpp
@@ -1,25 +1,86 @@
 #include "tagitem.h"

 

+#include <QPainter>

+#include <QGuiApplication>

+

 TagItem::TagItem(const Tag &tag)

     : valid(true)

 {

     setFlags(QGraphicsItem::ItemIsMovable

              | QGraphicsItem::ItemIsSelectable

-             | QGraphicsItem::ItemIsFocusable);

-    /* TODO text_it.setFlags(QGraphicsItem::ItemIgnoresTransformations);

-     */

+             | QGraphicsItem::ItemIsFocusable

+             | QGraphicsItem::ItemIgnoresTransformations

+             | QGraphicsItem::ItemSendsGeometryChanges);

+    QFont font(QGuiApplication::font());

+    font.setPointSize(18);

+    setFont(font);

     tagUpdated(tag);

 }

 

 void TagItem::tagUpdated(const Tag &tag)

 {

     m_tag = tag;

+    qDebug() << "TagItem updated" << tag.name << tag.anchor;

     setText(tag.name);

     setPos(tag.anchor);

 }

 

+QRectF TagItem::boundingRect() const

+{

+    QRectF parentRect(QGraphicsSimpleTextItem::boundingRect());

+    parentRect.translate(-(parentRect.bottomRight() - parentRect.topLeft()) * 0.5);

+    return parentRect.marginsAdded(QMargins(5, 5, 5, 5));

+}

+

+/* For some reason this is not exposed through the public API so we have to copy-paste it here m( */

+static void paintSelectionHighlightBorder(QPainter *painter, const QStyleOptionGraphicsItem *option, TagItem *item)

+{

+        const QRectF mbrect = painter->transform().mapRect(item->boundingRect());

+        if (qMin(mbrect.width(), mbrect.height()) < qreal(1.0))

+            return;

+

+        const qreal pad = item->pen().widthF() / 2;

+        const qreal penWidth = 0; // cosmetic pen

+        const QColor fgcolor = option->palette.windowText().color();

+        const QColor bgcolor( // ensure good contrast against fgcolor

+            fgcolor.red()   > 127 ? 0 : 255,

+            fgcolor.green() > 127 ? 0 : 255,

+            fgcolor.blue()  > 127 ? 0 : 255);

+        painter->setPen(QPen(bgcolor, penWidth, Qt::SolidLine));

+        painter->setBrush(Qt::NoBrush);

+        painter->drawRect(item->boundingRect().adjusted(pad, pad, -pad, -pad));

+        painter->setPen(QPen(option->palette.windowText(), 0, Qt::DashLine));

+        painter->setBrush(Qt::NoBrush);

+        painter->drawRect(item->boundingRect().adjusted(pad, pad, -pad, -pad));

+}

+

+void TagItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)

+{

+    painter->setBrush(Qt::white);

+    painter->drawRect(boundingRect());

+

+    QRectF parentRect(QGraphicsSimpleTextItem::boundingRect());

+    QPointF pos = (parentRect.bottomRight() - parentRect.topLeft()) * 0.5;

+    painter->translate(-pos);

+

+    QStyleOptionGraphicsItem newOption(*option);

+    newOption.state = ~(QStyle::State_Selected |QStyle::State_HasFocus);

+    QGraphicsSimpleTextItem::paint(painter, &newOption, widget);

+

+    painter->translate(pos);

+    if (option->state & (QStyle::State_Selected | QStyle::State_HasFocus))

+        paintSelectionHighlightBorder(painter, option, this);

+}

+

+QPainterPath TagItem::shape() const

+{

+    QPainterPath path;

+    return QGraphicsItem::shape();

+}

+

 QVariant TagItem::itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value)

 {

+    qDebug() << "itemChange" << m_tag.name << this->boundingRect() << change;

     if (change == ItemPositionChange) {

         /* https://gist.github.com/csukuangfj/c2a06416062bec9ed99eddd705c21275#file-qgraphicsscenetest-cpp-L90

          *

diff --git a/tagitem.h b/tagitem.h
index a248243..3863d40 100644
--- a/tagitem.h
+++ b/tagitem.h
@@ -14,13 +14,14 @@ public:
 

     enum { TagItemType = UserType + 1 };

     int type() const override { return TagItemType; }

-

     bool isValid() { return valid; }

-

     void tagUpdated(const Tag &tag);

-

     Tag tag() { return m_tag; }

 

+    virtual QRectF boundingRect() const override;

+    virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) override;

+    virtual QPainterPath shape() const override;

+

 protected:

     QVariant itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value) override;

 

diff --git a/taglistmodel.cpp b/taglistmodel.cpp
index e3ba006..d68fc57 100644
--- a/taglistmodel.cpp
+++ b/taglistmodel.cpp
@@ -4,6 +4,7 @@ TagListModel::TagListModel(SQLiteSaveFile &backend)
     : backend(backend)

     , cached_tags(backend.getAllTags())

 {

+    qDebug() << "connecting TagListModel" << &backend;

     connect(&backend, &SQLiteSaveFile::tagChange,

             [=](TagChange change, const Tag &tag) { Q_UNUSED(change); Q_UNUSED(tag); reloadTags(); });

     connect(&backend, &SQLiteSaveFile::fileReload,

@@ -28,10 +29,11 @@ QVariant TagListModel::data(const QModelIndex &index, int role) const
     if (!index.isValid())

         return QVariant();

 

-    if (role != Qt::DisplayRole)

+    if (role != Qt::DisplayRole && role != Qt::EditRole)

         return QVariant();

 

-    return cached_tags.at(index.row()).name;

+    auto rv = cached_tags.at(index.row()).name;

+    return rv;

 }

 

 QVariant TagListModel::headerData(int section, Qt::Orientation orientation, int role) const

diff --git a/taglistmodel.h b/taglistmodel.h
index 41fa520..d4bd5df 100644
--- a/taglistmodel.h
+++ b/taglistmodel.h
@@ -7,6 +7,8 @@
 

 class TagListModel : public QAbstractListModel

 {

+    Q_OBJECT

+

 public:

     TagListModel(SQLiteSaveFile &backend);

 

diff --git a/tagproptablemodel.cpp b/tagproptablemodel.cpp
index 711494d..4dc5e6b 100644
--- a/tagproptablemodel.cpp
+++ b/tagproptablemodel.cpp
@@ -1,26 +1,24 @@
 #include "tagproptablemodel.h"

 

 TagPropTableModel::TagPropTableModel(SQLiteSaveFile &backend, const Tag tag)

-    : backend(backend)

-    , tag_cached(tag)

-    , tagIsValid(true)

+    : TagPropTableModel(backend, true)

 {

+    tag_cached = tag;

     tag_keys = tag_cached.metadata.keys();

     tag_keys.sort();

-    connect(&backend, &SQLiteSaveFile::tagChange,

-            this, &TagPropTableModel::tagChange);

-    connect(&backend, &SQLiteSaveFile::fileReload,

-            [=]() {

-        beginResetModel();

-        tagIsValid = false;

-        endResetModel();

-    });

+    qDebug() << "connecting TagPropTableModel" << &backend;

 }

 

-TagPropTableModel::TagPropTableModel(SQLiteSaveFile &backend)

+TagPropTableModel::TagPropTableModel(SQLiteSaveFile &backend, bool tagIsValid)

     : backend(backend)

-    , tagIsValid(false)

+    , tagIsValid(tagIsValid)

 {

+    connect(&backend, &SQLiteSaveFile::tagChange, this, &TagPropTableModel::tagChange);

+    connect(&backend, &SQLiteSaveFile::fileReload, [=]() {

+        beginResetModel();

+        this->tagIsValid = false;

+        endResetModel();

+    });

 }

 

 int TagPropTableModel::rowCount(const QModelIndex &parent) const

@@ -42,7 +40,7 @@ QVariant TagPropTableModel::data(const QModelIndex &index, int role) const
     if (!index.isValid())

         return QVariant();

 

-    if (role != Qt::DisplayRole)

+    if (role != Qt::DisplayRole && role != Qt::EditRole)

         return QVariant();

 

     bool label = index.column() == 0;

@@ -50,7 +48,7 @@ QVariant TagPropTableModel::data(const QModelIndex &index, int role) const
     switch (index.row()) {

     case 0: return label ? QVariant("Database ID")    : tag_cached.id;   break;

     case 1: return label ? QVariant("Label")          : tag_cached.name; break;

-    case 2: return label ? QVariant("Anchor")         : tag_cached.anchor; break;

+    case 2: return label ? QVariant("Anchor")         : QString("%1, %2").arg(tag_cached.anchor.x()).arg(tag_cached.anchor.y()); break;

     }

 

     int idx = index.row() - 3;

@@ -100,18 +98,19 @@ bool TagPropTableModel::setData(const QModelIndex &index, const QVariant &value,
     if (role != Qt::EditRole)

         return false;

 

-    if (index.row() == 1)

+    if (index.row() == 1) {

         tag_cached.name = value.toString();

-    else if (index.row() < 3)

+    } else if (index.row() < 3) {

         return false;

-

-    int idx = index.row() - 3;

-    if (index.column() == 0) { /* key changed */

-        /* move value to new key and delete old key */

-        tag_cached.metadata[value.toString()] = tag_cached.metadata[tag_keys[idx]];

-        tag_cached.metadata.remove(tag_keys[idx]);

     } else {

-        tag_cached.metadata[tag_keys[idx]] = value.toString();

+        int idx = index.row() - 3;

+        if (index.column() == 0) { /* key changed */

+            /* move value to new key and delete old key */

+            tag_cached.metadata[value.toString()] = tag_cached.metadata[tag_keys[idx]];

+            tag_cached.metadata.remove(tag_keys[idx]);

+        } else {

+            tag_cached.metadata[tag_keys[idx]] = value.toString();

+        }

     }

 

     backend.updateTag(tag_cached);

@@ -120,13 +119,17 @@ bool TagPropTableModel::setData(const QModelIndex &index, const QVariant &value,
 

 void TagPropTableModel::tagChange(TagChange change, const Tag &tag)

 {

+    auto dbg = qDebug() << QString("TagPropTableModel::tagChange(%1, %2 \"%3\")").arg(change).arg(tag.id).arg(tag.name);

     if (tag.id != tag_cached.id)

         return;

 

     assert(change != TagChange::CREATED);

     if (change == TagChange::CHANGED) {

+        dbg << "changed";

         showTag(tag);

+

     } else if (change == TagChange::DELETED) {

+        dbg << "deleted";

         beginResetModel();

         tagIsValid = false;

         endResetModel();

@@ -140,5 +143,6 @@ void TagPropTableModel::showTag(const Tag &tag)
     tag_cached = tag;

     tag_keys = tag_cached.metadata.keys();

     tag_keys.sort();

+    tagIsValid = true;

     endResetModel();

 }

diff --git a/tagproptablemodel.h b/tagproptablemodel.h
index b127f90..09ab8b4 100644
--- a/tagproptablemodel.h
+++ b/tagproptablemodel.h
@@ -9,8 +9,10 @@
 

 class TagPropTableModel : public QAbstractTableModel

 {

+    Q_OBJECT

+

 public:

-    TagPropTableModel(SQLiteSaveFile &backend);

+    TagPropTableModel(SQLiteSaveFile &backend) : TagPropTableModel(backend, false) {};

     TagPropTableModel(SQLiteSaveFile &backend, const Tag tag);

 

     int rowCount(const QModelIndex &parent=QModelIndex()) const override;

@@ -27,6 +29,8 @@ private slots:
     void tagChange(TagChange change, const Tag &tag);

 

 private:

+    TagPropTableModel(SQLiteSaveFile &backend, bool tagIsValid);

+

     SQLiteSaveFile &backend;

     Tag tag_cached;

     QStringList tag_keys;

diff --git a/tagscene.cpp b/tagscene.cpp
index fb52574..a6efd17 100644
--- a/tagscene.cpp
+++ b/tagscene.cpp
@@ -2,15 +2,16 @@
 
 #include <QGraphicsSceneMouseEvent>
 
-TagScene::TagScene(SQLiteSaveFile &proj)
-    : proj(proj)
-{
-    reloadPicture();
-    reloadTags();
+void TagScene::setProject(SQLiteSaveFile *proj) {
+    if (m_proj)
+        disconnect(m_proj, nullptr, this, nullptr);
+    m_proj = proj;
+
+    reloadScene();
 
-    connect(&proj, &SQLiteSaveFile::tagChange, this, &TagScene::tagChanged);
-    connect(&proj, &SQLiteSaveFile::fileReload,
-            [=]() { reloadTags(); });
+    connect(m_proj, &SQLiteSaveFile::tagChange, this, &TagScene::tagChanged);
+    connect(m_proj, &SQLiteSaveFile::fileReload, this, &TagScene::reloadScene);
+    connect(m_proj, &SQLiteSaveFile::imageLoaded, this, &TagScene::reloadPicture);
 }
 
 void TagScene::tagChanged(TagChange change, const Tag &tag)
@@ -40,11 +41,22 @@ void TagScene::tagChanged(TagChange change, const Tag &tag)
 
 void TagScene::reloadPicture()
 {
-    pix.loadFromData(proj.getImage());
+    if (!m_proj)
+        return;
+
+    pix.loadFromData(m_proj->getImage());
     if (pix_it)
         removeItem(pix_it);
     pix_it = new QGraphicsPixmapItem(pix);
+    pix_it->setZValue(-1);
     addItem(pix_it);
+    QRectF imgBounds = pix_it->boundingRect();
+    imgBounds = imgBounds.marginsAdded(QMargins(imgBounds.width() * 0.5, imgBounds.height() * 0.5, imgBounds.width() * 0.5, imgBounds.height() * 0.5));
+    setSceneRect(itemsBoundingRect().united(imgBounds));
+    qDebug() << "TagScene: reloadPicture()" << pix_it->boundingRect() << pix_it << pix << pix_it->isActive();
+
+    invalidate();
+    imageLoaded();
 }
 
 void TagScene::addTag(const Tag tag) {
@@ -53,16 +65,20 @@ void TagScene::addTag(const Tag tag) {
     tags[tag.id] = it;
 }
 
-void TagScene::reloadTags()
+void TagScene::reloadScene()
 {
     clear();
-    for (auto *it : tags.values()) {
+    for (auto *it : tags.values())
         delete it;
-    }
+    pix_it = nullptr;
 
-    for (const Tag &tag : proj.getAllTags()) {
+    if (!m_proj)
+        return;
+
+    for (const Tag &tag : m_proj->getAllTags())
         addTag(tag);
-    }
+
+    reloadPicture(); /* calls invalidate() for us */
 }
 
 void TagScene::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
@@ -70,11 +86,18 @@ void TagScene::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
     QGraphicsItem *it = itemAt(event->scenePos(), QTransform());
     if (!it) {
         QGraphicsScene::mouseDoubleClickEvent(event);
+        return;
+    }
+
+    if (it == pix_it) {
+        m_proj->createTagAt(event->scenePos());
+        return;
     }
 
     TagItem *tagitem = qgraphicsitem_cast<TagItem *>(it);
     if (!tagitem) {
         QGraphicsScene::mouseDoubleClickEvent(event);
+        return;
     }
 
     tagDoubleClicked(tagitem->tag());
diff --git a/tagscene.h b/tagscene.h
index 006fffd..4c81fe5 100644
--- a/tagscene.h
+++ b/tagscene.h
@@ -14,14 +14,18 @@ class TagScene : public QGraphicsScene
     Q_OBJECT
 
 public:
-    TagScene(SQLiteSaveFile &proj);
+    TagScene() {}
+    const QGraphicsPixmapItem *backgroundPixmapItem() const { return pix_it; }
 
 public slots:
     void reloadPicture();
-    void reloadTags();
+    void reloadScene();
+
+    void setProject(SQLiteSaveFile *proj);
 
 signals:
     void tagDoubleClicked(const Tag &tag);
+    void imageLoaded();
 
 protected:
     void mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event) override;
@@ -32,9 +36,9 @@ private slots:
 private:
     void addTag(const Tag tag);
 
-    SQLiteSaveFile &proj;
+    SQLiteSaveFile *m_proj = nullptr;
 
-    QGraphicsPixmapItem *pix_it;
+    QGraphicsPixmapItem *pix_it = nullptr;
     QPixmap pix;
     QMap<long long int, TagItem*> tags;
 };
diff --git a/tagview.cpp b/tagview.cpp
index b4e83dd..9a9c9a0 100644
--- a/tagview.cpp
+++ b/tagview.cpp
@@ -4,34 +4,41 @@
 #include <QScrollBar>
 #include <cmath>
 
-TagView::TagView(SQLiteSaveFile &proj)
-    : scene(proj)
-    , proj(proj)
-    , saveCenterTimer()
+TagView::TagView(QWidget *parent)
+    : QGraphicsView(parent)
+    , saveCenterTimer(this)
 {
     setDragMode(QGraphicsView::ScrollHandDrag);
-    setScene(&scene);
-    connect(&scene, &TagScene::tagDoubleClicked, this, &TagView::tagDoubleClicked);
+    setScene(&m_scene);
+    connect(&m_scene, &TagScene::tagDoubleClicked, this, &TagView::tagDoubleClicked);
+    connect(&m_scene, &TagScene::imageLoaded, this, &TagView::zoomToFit);
 
     saveCenterTimer.setSingleShot(true);
     saveCenterTimer.setInterval(500);
-    connect(&saveCenterTimer, &QTimer::timeout,
-            this, &TagView::saveCenter);
+    connect(&saveCenterTimer, &QTimer::timeout, this, &TagView::saveCenter);
+}
+
+TagView::~TagView()
+{
+    were_done = true;
 }
 
 void TagView::zoomToFit()
 {
     QTransform tx = QTransform().rotate(-rotation);
-    QRectF rect = tx.mapRect(scene.itemsBoundingRect());
+    QRectF rect = tx.mapRect(m_scene.itemsBoundingRect());
     QRectF vp = viewport()->rect();
 
     setZoom(qMin(vp.width()/rect.width(), vp.height()/rect.height()));
+    centerOn(m_scene.backgroundPixmapItem());
+    qDebug() << "TagView::zoomToFit():" << sceneRect() << rect << viewport()->rect();
 }
 
 void TagView::setZoom(qreal zoom)
 {
     this->zoom = zoom;
-    proj.setMeta("view_zoom", zoom);
+    if (m_proj)
+        m_proj->setMeta("view_zoom", zoom);
     setTransform(QTransform::fromScale(zoom, zoom).rotate(rotation));
 }
 
@@ -47,7 +54,15 @@ void TagView::rotate(int angle)
     if (tmp < 0)
         tmp += 360;
     rotation = tmp;
-    proj.setMeta("view_rotation", rotation);
+    if (m_proj)
+        m_proj->setMeta("view_rotation", rotation);
+}
+
+void TagView::setProject(SQLiteSaveFile *proj)
+{
+    m_proj = proj;
+    m_scene.setProject(m_proj);
+    restoreViewport();
 }
 
 void TagView::wheelEvent(QWheelEvent *evt)
@@ -63,22 +78,34 @@ void TagView::wheelEvent(QWheelEvent *evt)
     }
 }
 
+void TagView::scrollContentsBy(int dx, int dy)
+{
+    QGraphicsView::scrollContentsBy(dx, dy);
+    /* Hackety hack: On object destruction this method is called downstream in the destructor chain. Prevent segfaults from calling an uninitialized timer. */
+    if (!were_done)
+        saveCenterTimer.start();
+}
+
 void TagView::saveCenter()
 {
     QPointF p = mapToScene(viewport()->rect().center());
-    proj.setMeta("view_center", QJsonDocument(QJsonArray({p.x(), p.y()})).toJson());
+    if (m_proj)
+        m_proj->setMeta("view_center", QJsonDocument(QJsonArray({p.x(), p.y()})).toJson());
 }
 
 void TagView::restoreViewport()
 {
-    QVariant v_rot = proj.getMeta("view_rotation");
+    if (!m_proj)
+        return;
+
+    QVariant v_rot = m_proj->getMeta("view_rotation");
     if (v_rot.isValid()) {
         rotation = v_rot.toInt();
     } else {
         rotation = 0;
     }
 
-    QVariant v_zoom = proj.getMeta("view_zoom");
+    QVariant v_zoom = m_proj->getMeta("view_zoom");
     if (v_zoom.isValid()) {
         zoom = v_zoom.toDouble();
         setTransform(QTransform::fromScale(zoom, zoom).rotate(rotation));
@@ -86,13 +113,13 @@ void TagView::restoreViewport()
         zoomToFit();
     }
 
-    QVariant v_center = proj.getMeta("view_center");
+    QVariant v_center = m_proj->getMeta("view_center");
     if (v_center.isValid()) {
         QJsonArray arr = QJsonDocument::fromJson(v_center.toByteArray()).toVariant().toJsonArray();
         assert(arr.size() == 2);
         assert(arr[0].isDouble() && arr[1].isDouble());
         centerOn(QPointF(arr[0].toDouble(), arr[1].toDouble()));
     } else {
-        centerOn(scene.itemsBoundingRect().center());
+        centerOn(m_scene.itemsBoundingRect().center());
     }
 }
diff --git a/tagview.h b/tagview.h
index 71b418c..edafcf4 100644
--- a/tagview.h
+++ b/tagview.h
@@ -13,19 +13,24 @@ class TagView : public QGraphicsView
     Q_OBJECT
 
 public:
-    TagView(SQLiteSaveFile &proj);
+    TagView(QWidget *parent=nullptr);
+    virtual ~TagView();
 
 public slots:
     void zoomToFit();
     void setZoom(qreal zoom);
-    void zoomIn(qreal delta);
+    void zoomIn(qreal delta=120);
+    void zoomOut(qreal delta=120) { zoomIn(-delta); }
     void rotate(int angle);
 
+    void setProject(SQLiteSaveFile *proj);
+
 signals:
     void tagDoubleClicked(const Tag &tag);
 
 protected:
     void wheelEvent(QWheelEvent *evt) override;
+    void scrollContentsBy(int dx, int dy) override;
 
 private slots:
     void saveCenter();
@@ -33,9 +38,10 @@ private slots:
 private:
     void restoreViewport();
 
-    TagScene scene;
-    SQLiteSaveFile &proj;
     QTimer saveCenterTimer;
+    bool were_done = false;
+    TagScene m_scene;
+    SQLiteSaveFile *m_proj = nullptr;
     int rotation;
     double zoom;
 };