move pan input into an InputMapper

src/ui/InputMapper.cpp

@@ -0,0 +1,70 @@
+#include "InputMapper.h"
+
+#include <memory>
+
+#include <QKeyEvent>
+
+#include "EventManager.h"
+#include "PanDirectionChangedEvent.h"
+
+bool InputMapper::handleKeyPress(QKeyEvent* event)
+{
+    // Auto-repeat says nothing new about which keys are down, and a held action is
+    // already held.
+    if (event->isAutoRepeat()) { return false; }
+
+    switch (event->key())
+    {
+    case Qt::Key_A:
+        m_panLeftHeld = true;
+        updatePanDirection();
+        return true;
+    case Qt::Key_D:
+        m_panRightHeld = true;
+        updatePanDirection();
+        return true;
+    default:
+        return false;
+    }
+}
+
+bool InputMapper::handleKeyRelease(QKeyEvent* event)
+{
+    if (event->isAutoRepeat()) { return false; }
+
+    switch (event->key())
+    {
+    case Qt::Key_A:
+        m_panLeftHeld = false;
+        updatePanDirection();
+        return true;
+    case Qt::Key_D:
+        m_panRightHeld = false;
+        updatePanDirection();
+        return true;
+    default:
+        return false;
+    }
+}
+
+void InputMapper::releaseAll()
+{
+    m_panLeftHeld  = false;
+    m_panRightHeld = false;
+    updatePanDirection();
+}
+
+void InputMapper::updatePanDirection()
+{
+    // Holding both keys cancels out rather than favouring one.
+    PanDirection direction = PanDirection::None;
+    if (m_panLeftHeld != m_panRightHeld)
+    {
+        direction = m_panLeftHeld ? PanDirection::Left : PanDirection::Right;
+    }
+
+    if (direction == m_panDirection) { return; }
+    m_panDirection = direction;
+    EventManager::getInstance()->sendEventImmediately(
+        std::make_shared<PanDirectionChangedEvent>(direction));
+}