1 files changed, 96 insertions, 0 deletions
diff --git a/tagview.cpp b/tagview.cpp
new file mode 100644
index 0000000..abaefcb
--- /dev/null
+++ b/tagview.cpp
@@ -0,0 +1,96 @@
+#include "tagview.h"
+
+#include <QWheelEvent>
+#include <QScrollBar>
+#include <cmath>
+
+TagView::TagView(SQLiteSaveFile &proj)
+    : proj(proj)
+    , saveCenterTimer()
+{
+    setDragMode(QGraphicsView::ScrollHandDrag);
+    setScene(&scene);
+
+    saveCenterTimer.setSingleShot(true);
+    saveCenterTimer.setInterval(500);
+    connect(&saveCenterTimer, &QTimer::timeout,
+            this, &TagView::saveCenter);
+}
+
+void TagView::zoomToFit()
+{
+    QTransform tx = QTransform().rotate(-rotation);
+    QRectF rect = tx.mapRect(scene.itemsBoundingRect());
+    QRectF vp = viewport()->rect();
+
+    setZoom(qMin(vp.width()/rect.width(), vp.height()/rect.height()));
+}
+
+void TagView::setZoom(qreal zoom)
+{
+    this->zoom = zoom;
+    proj.setMeta("view_zoom", zoom);
+    setTransform(QTransform::fromScale(zoom, zoom).rotate(rotation));
+}
+
+void TagView::zoomIn(qreal delta)
+{
+    setZoom(qMax(1.0/16, qMin(4.0, zoom * qPow(1.2, delta/120))));
+}
+
+void TagView::rotate(int angle)
+{
+    QGraphicsView::rotate(angle);
+    int tmp = (rotation + angle) % 360;
+    if (tmp < 0)
+        tmp += 360;
+    rotation = tmp;
+    proj.setMeta("view_rotation", rotation);
+}
+
+void TagView::wheelEvent(QWheelEvent *evt)
+{
+    if (evt->modifiers() == Qt::ControlModifier) {
+        zoomIn(evt->angleDelta().y());
+    } else {
+        if (qAbs(evt->angleDelta().x()) > qAbs(evt->angleDelta().y())) {
+            QCoreApplication::sendEvent(horizontalScrollBar(), evt);
+        } else {
+            QCoreApplication::sendEvent(verticalScrollBar(), evt);
+        }
+    }
+}
+
+void TagView::saveCenter()
+{
+    QPointF p = mapToScene(viewport()->rect().center());
+    proj.setMeta("view_center", QJsonDocument(QJsonArray({p.x(), p.y()})).toJson());
+}
+
+void TagView::restoreViewport()
+{
+    QVariant v_rot = proj.getMeta("view_rotation");
+    if (v_rot.isValid()) {
+        rotation = v_rot.toInt();
+    } else {
+        rotation = 0;
+    }
+
+    QVariant v_zoom = proj.getMeta("view_zoom");
+    if (v_zoom.isValid()) {
+        zoom = v_zoom.toDouble();
+        setTransform(QTransform::fromScale(zoom, zoom).rotate(rotation));
+    } else {
+        zoomToFit();
+    }
+
+    QVariant v_center = 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());
+    }
+}