Allow pen input

src/eventfilter.cpp

@@ -0,0 +1,151 @@
+#include "eventfilter.h"
+
+#include <QTimer>
+#include <QMouseEvent>
+#include <QTabletEvent>
+#include <QScreen>
+#include <QGuiApplication>
+
+#define DISPLAYWIDTH 1404
+#define DISPLAYHEIGHT 1872.0
+#define WACOM_X_SCALAR (float(DISPLAYWIDTH) / float(DISPLAYHEIGHT))
+#define WACOM_Y_SCALAR (float(DISPLAYHEIGHT) / float(DISPLAYWIDTH))
+#define DEBUG_EVENTS
+#ifdef DEBUG_EVENTS
+#define O_DEBUG_EVENT(msg) qDebug() << msg
+#else
+#define O_DEBUG_EVENT(msg)
+#endif
+
+EventFilter::EventFilter(QObject *parent) : QObject(parent), root(nullptr){}
+
+QPointF swap(QPointF pointF){
+    return QPointF(pointF.y(), pointF.x());
+}
+
+QPointF transpose(QPointF pointF){
+    pointF = swap(pointF);
+    // Handle scaling from wacom to screensize
+    pointF.setX(pointF.x() * WACOM_X_SCALAR);
+    pointF.setY((DISPLAYWIDTH - pointF.y()) * WACOM_Y_SCALAR);
+    return pointF;
+}
+QPointF globalPos(QQuickItem* obj){
+    qreal x = obj->x();
+    qreal y = obj->y();
+    while(obj->parentItem() != nullptr){
+        obj = obj->parentItem();
+        x += obj->x();
+        y += obj->y();
+    }
+    return QPointF(x, y);
+}
+QMouseEvent* toMouseEvent(QEvent::Type type, QEvent* ev){
+    auto tabletEvent = static_cast<QTabletEvent*>(ev);
+    return new QMouseEvent(
+        type,
+        transpose(tabletEvent->posF()),
+        transpose(tabletEvent->globalPosF()),
+        transpose(tabletEvent->globalPosF()),
+        tabletEvent->button(),
+        tabletEvent->buttons(),
+        tabletEvent->modifiers()
+    );
+}
+bool isAt(QQuickItem* item, QPointF pos){
+    auto itemPos = globalPos(item);
+    auto otherItemPos = QPointF(itemPos.x() + item->width(), itemPos.y() + item->height());
+    return pos.x() >= itemPos.x() && pos.x() <= otherItemPos.x() && pos.y() >= itemPos.y() && pos.y() <= otherItemPos.y();
+}
+QList<QObject*> widgetsAt(QQuickItem* root, QPointF pos){
+    QList<QObject*> result;
+    auto children = root->findChildren<QQuickItem*>();
+    for(auto child : children){
+        if(result.contains(child)){
+            continue;
+        }
+        if(!child->isVisible() || !child->isEnabled()){
+            continue;
+        }
+        if(child->acceptedMouseButtons() & Qt::LeftButton && isAt(child, pos)){
+            result.append((QObject*)child);
+            for(auto item : widgetsAt(child, pos)){
+                if(!result.contains(item)){
+                    result.append(item);
+                }
+            }
+            continue;
+        }
+        if(!child->clip()){
+            for(auto item : widgetsAt(child, pos)){
+                if(!result.contains(item)){
+                    result.append(item);
+                }
+            }
+        }
+    }
+    return result;
+}
+int parentCount(QQuickItem* obj){
+    int count = 0;
+    while(obj->parentItem()){
+        count++;
+        obj = obj->parentItem();
+    }
+    return count;
+}
+void postEvent(QEvent::Type type, QEvent* ev, QQuickItem* root){
+    auto mouseEvent = toMouseEvent(type, ev);
+    auto pos = mouseEvent->globalPos();
+    for(auto postWidget : widgetsAt(root, pos)){
+        if(parentCount((QQuickItem*)postWidget)){
+            O_DEBUG_EVENT("postWidget: " << postWidget);
+            auto event = new QMouseEvent(
+                mouseEvent->type(), mouseEvent->localPos(), mouseEvent->windowPos(),
+                mouseEvent->screenPos(), mouseEvent->button(), mouseEvent->buttons(),
+                mouseEvent->modifiers()
+            );
+            auto widgetPos = globalPos((QQuickItem*)postWidget);
+            auto localPos = event->localPos();
+            localPos.setX(pos.x() - widgetPos.x());
+            localPos.setY((pos.y()) - widgetPos.y());
+            event->setLocalPos(localPos);
+            QGuiApplication::postEvent(postWidget, event);
+        }
+    }
+    delete mouseEvent;
+}
+
+bool EventFilter::eventFilter(QObject* obj, QEvent* ev){
+    auto type = ev->type();
+    bool filtered = QObject::eventFilter(obj, ev);
+    if(!filtered){
+        if(type == QEvent::TabletPress){
+            O_DEBUG_EVENT(ev << ev->isAccepted());
+            postEvent(QMouseEvent::MouseButtonPress, ev, root);
+        }else if(type == QEvent::TabletRelease){
+            O_DEBUG_EVENT(ev << ev->isAccepted());
+            postEvent(QMouseEvent::MouseButtonRelease, ev, root);
+        }else if(type == QEvent::TabletMove){
+            O_DEBUG_EVENT(ev << ev->isAccepted());
+            postEvent(QMouseEvent::MouseMove, ev, root);
+        }
+#ifdef DEBUG_EVENTS
+        else if(
+            type != QEvent::MetaCall
+            && type != QEvent::SockAct
+            && type != QEvent::SockClose
+            && type != QEvent::ChildAdded
+            && type != QEvent::ChildPolished
+            && type != QEvent::ChildRemoved
+            && type != QEvent::Timer
+            && type != QEvent::UpdateRequest
+        ){
+            O_DEBUG_EVENT(ev << ev->isAccepted() << obj);
+        }
+#endif
+    }
+    return filtered;
+}
+
+#include "moc_eventfilter.cpp"

src/eventfilter.h

@@ -0,0 +1,37 @@
+#pragma once
+
+
+#include <QObject>
+#include <QEvent>
+#include <QQuickItem>
+
+/*!
+ * \brief An event filter that maps pen events to Qt touch events.
+ *
+ * It works by handling tablet events and translating them to mouse events.
+ * They are then sent to every enabled/visible widget at the x/y coordinate that have a parent widget, and accept left mouse button input.
+ * This doens't always work as some widgets aren't found with the current method of finding widgets at a location.
+ *
+ * The following is an example of adding it to an application:
+ * \snippet examples/oxide.cpp EventFilter
+ */
+class EventFilter : public QObject
+{
+    Q_OBJECT
+public:
+    /*!
+     * \brief The root element in the Qt application
+     *
+     * This is needed to find wigets to send mouse events when a pen touch is detected
+     */
+    QQuickItem* root;
+    /*!
+     * \brief Create a new EventFilter instance
+     * \param parent The parent object. Usually should be qApp
+     */
+    explicit EventFilter(QObject* parent = nullptr);
+signals:
+    void suspend();
+protected:
+    bool eventFilter(QObject* obj, QEvent* ev);
+};

src/main.cpp

@@ -6,6 +6,8 @@
 #include <cstdlib>
 #include <signal.h>
 
+#include "eventfilter.h"
+
 #ifdef EPAPER
 // This is required for Qt to display to the reMarkable's display
 Q_IMPORT_PLUGIN(QsgEpaperPlugin)
@@ -53,6 +55,8 @@ int main(int argc, char *argv[]){
     qDebug() << "Desktop detected...";
 #endif
     QGuiApplication app(argc, argv);
+    auto filter = new EventFilter(&app);
+    app.installEventFilter(filter);
     app.setApplicationName("gameboy");
     app.setApplicationDisplayName("Gameboy Emulator");
     app.setApplicationVersion(APP_VERSION);
@@ -64,6 +68,8 @@ int main(int argc, char *argv[]){
         qDebug() << "Nothing to display";
         return -1;
     }
+    auto root = engine.rootObjects().first();
+    filter->root = (QQuickItem*)root;
 
     // Setup some signal handlers to make sure to quit the application normally if these signals are recieved
     signal(SIGINT, sigHandler);

src/src.pro

@@ -22,6 +22,7 @@ DEFINES += QT_DEPRECATED_WARNINGS
 DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x051510
 
 SOURCES += \
+        eventfilter.cpp \
         main.cpp
 
 # This provides more context on crashes when built in debug mode
@@ -77,6 +78,7 @@ linux-oe-g++ {
 }
 
 HEADERS += \
+    eventfilter.h \
     gameboy.h \
     gameboythread.h