[pim/mimetreeparser] src/quick: Add basic wheel interceptor

Git commit 8d2b3512eb2e5b9276b0f3f760274f5fa9abc912 by Claudio Cambra.
Committed on 16/08/2026 at 16:51.
Pushed by clau-cambra into branch 'master'.

Add basic wheel interceptor

a

M  +4    -0    src/quick/CMakeLists.txt
A  +88   -0    src/quick/wheelinterceptor.cpp     [License: LGPL(v2.1+)]
A  +35   -0    src/quick/wheelinterceptor.h     [License: LGPL(v2.1+)]

https://invent.kde.org/pim/mimetreeparser/-/commit/8d2b3512eb2e5b9276b0f3f760274f5fa9abc912

diff --git a/src/quick/CMakeLists.txt b/src/quick/CMakeLists.txt
index 0c8ae6e..86062a1 100644
--- a/src/quick/CMakeLists.txt
+++ b/src/quick/CMakeLists.txt
@@ -16,12 +16,16 @@ target_sources(
         itinerarymodel.cpp
         itinerarymodel.h
         types.h
+        wheelinterceptor.h
+        wheelinterceptor.cpp
 )
 
 target_link_libraries(
     mimetreeparser_plugin
     PRIVATE
         Qt::Qml
+        Qt::Quick
+        Qt::Gui
         ${DBUS_LIB}
         KPim6::MimeTreeParserCore
         KF6::KIOGui
diff --git a/src/quick/wheelinterceptor.cpp b/src/quick/wheelinterceptor.cpp
new file mode 100644
index 0000000..8be10fb
--- /dev/null
+++ b/src/quick/wheelinterceptor.cpp
@@ -0,0 +1,88 @@
+// SPDX-FileCopyrightText: 2025 Claudio Cambra <[email protected]>
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include "wheelinterceptor.h"
+
+#include <QCoreApplication>
+#include <QGuiApplication>
+#include <QStyleHints>
+#include <QWheelEvent>
+
+WheelInterceptor::WheelInterceptor(QObject *parent)
+    : QObject(parent)
+{
+}
+
+QQuickItem *WheelInterceptor::source() const
+{
+    return m_source;
+}
+
+void WheelInterceptor::setSource(QQuickItem *source)
+{
+    if (m_source == source) {
+        return;
+    }
+    if (m_source) {
+        QCoreApplication::instance()->removeEventFilter(this);
+    }
+    m_source = source;
+    if (m_source) {
+        QCoreApplication::instance()->installEventFilter(this);
+    }
+    Q_EMIT sourceChanged();
+}
+
+QQuickItem *WheelInterceptor::target() const
+{
+    return m_target;
+}
+
+void WheelInterceptor::setTarget(QQuickItem *target)
+{
+    if (m_target == target) {
+        return;
+    }
+    m_target = target;
+    Q_EMIT targetChanged();
+}
+
+static QQuickItem *findTopmostFlickable(QQuickItem *item)
+{
+    QQuickItem *topmost = nullptr;
+    auto current = item;
+    while (current) {
+        if (current->inherits("QQuickFlickable")) {
+            topmost = current;
+        }
+        current = current->parentItem();
+    }
+    return topmost;
+}
+
+bool WheelInterceptor::eventFilter(QObject *obj, QEvent *event)
+{
+    Q_UNUSED(obj);
+    if (event->type() == QEvent::Wheel && m_source && m_target) {
+        auto wheelEvent = static_cast<QWheelEvent *>(event);
+        const auto localPos = m_source->mapFromGlobal(wheelEvent->globalPosition().toPoint());
+        if (m_source->contains(localPos)) {
+            auto flickable = findTopmostFlickable(m_source);
+            if (!flickable) {
+                flickable = findTopmostFlickable(m_target);
+            }
+            if (flickable) {
+                const auto viewH = flickable->height();
+                const auto contentH = flickable->property("contentHeight").toReal();
+                const auto currentY = flickable->property("contentY").toReal();
+                const auto maxScroll = qMax(0.0, contentH - viewH);
+                const auto delta = wheelEvent->angleDelta().y();
+                const auto scrollLines = QGuiApplication::styleHints()->wheelScrollLines();
+                const auto pixels = -(delta / 120.0) * scrollLines * 20.0;
+                flickable->setProperty("contentY", qBound(0.0, currentY + pixels, maxScroll));
+                return true;
+            }
+        }
+    }
+    return false;
+}
diff --git a/src/quick/wheelinterceptor.h b/src/quick/wheelinterceptor.h
new file mode 100644
index 0000000..fa9006d
--- /dev/null
+++ b/src/quick/wheelinterceptor.h
@@ -0,0 +1,35 @@
+// SPDX-FileCopyrightText: 2025 Claudio Cambra <[email protected]>
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#pragma once
+
+#include <QObject>
+#include <QQuickItem>
+
+class WheelInterceptor : public QObject
+{
+    Q_OBJECT
+    QML_ELEMENT
+    Q_PROPERTY(QQuickItem *source READ source WRITE setSource NOTIFY sourceChanged)
+    Q_PROPERTY(QQuickItem *target READ target WRITE setTarget NOTIFY targetChanged)
+
+public:
+    explicit WheelInterceptor(QObject *parent = nullptr);
+
+    QQuickItem *source() const;
+    void setSource(QQuickItem *source);
+
+    QQuickItem *target() const;
+    void setTarget(QQuickItem *target);
+
+protected:
+    bool eventFilter(QObject *obj, QEvent *event) override;
+
+Q_SIGNALS:
+    void sourceChanged();
+    void targetChanged();
+
+private:
+    QQuickItem *m_source = nullptr;
+    QQuickItem *m_target = nullptr;
+};