Support tablet devices

Process QTabletEvents and forward them to Chromium in order to
support pressure, tilting, rotation, eraser and similar
features of tablet devices.

Change-Id: I763d9e6e7036c29715a0b5531d3c6363eb4fcd8c
Reviewed-by: Michael Brüning <michael.bruning@qt.io>

5 files changed, 179 insertions, 46 deletions

diff --git a/src/core/render_widget_host_view_qt.cpp b/src/core/render_widget_host_view_qt.cpp
index 9be5bd498..7ce71a81d 100644
--- a/src/core/render_widget_host_view_qt.cpp
+++ b/src/core/render_widget_host_view_qt.cpp
@@ -957,6 +957,12 @@ bool RenderWidgetHostViewQt::forwardEvent(QEvent *event)
     case QEvent::TouchCancel:
         handleTouchEvent(static_cast<QTouchEvent*>(event));
         break;
+    case QEvent::TabletPress:
+        Focus(); // Fall through.
+    case QEvent::TabletRelease:
+    case QEvent::TabletMove:
+        handleTabletEvent(static_cast<QTabletEvent*>(event));
+        break;
 #ifndef QT_NO_GESTURES
     case QEvent::NativeGesture:
         handleGestureEvent(static_cast<QNativeGestureEvent *>(event));
@@ -1089,49 +1095,7 @@ void RenderWidgetHostViewQt::handleMouseEvent(QMouseEvent* event)
     // transformation done by Chromium.
     if (event->source() == Qt::MouseEventSynthesizedBySystem)
         return;
-
-    blink::WebMouseEvent webEvent = WebEventFactory::toWebMouseEvent(event, dpiScale());
-    if ((webEvent.GetType() == blink::WebInputEvent::kMouseDown || webEvent.GetType() == blink::WebInputEvent::kMouseUp)
-            && webEvent.button == blink::WebMouseEvent::Button::kNoButton) {
-        // Blink can only handle the 3 main mouse-buttons and may assert when processing mouse-down for no button.
-        return;
-    }
-
-
-    if (event->type() == QMouseEvent::MouseButtonPress) {
-        if (event->button() != m_clickHelper.lastPressButton
-            || (event->timestamp() - m_clickHelper.lastPressTimestamp > static_cast<ulong>(qGuiApp->styleHints()->mouseDoubleClickInterval()))
-            || (event->pos() - m_clickHelper.lastPressPosition).manhattanLength() > qGuiApp->styleHints()->startDragDistance())
-            m_clickHelper.clickCounter = 0;
-
-        m_clickHelper.lastPressTimestamp = event->timestamp();
-        webEvent.click_count = ++m_clickHelper.clickCounter;
-        m_clickHelper.lastPressButton = event->button();
-        m_clickHelper.lastPressPosition = QPointF(event->pos()).toPoint();
-    }
-
-    webEvent.movement_x = event->globalX() - m_previousMousePosition.x();
-    webEvent.movement_y = event->globalY() - m_previousMousePosition.y();
-
-    if (IsMouseLocked())
-        QCursor::setPos(m_previousMousePosition);
-    else
-        m_previousMousePosition = event->globalPos();
-
-    if (m_imeInProgress && event->type() == QMouseEvent::MouseButtonPress) {
-        m_imeInProgress = false;
-        // Tell input method to commit the pre-edit string entered so far, and finish the
-        // composition operation.
-#ifdef Q_OS_WIN
-        // Yes the function name is counter-intuitive, but commit isn't actually implemented
-        // by the Windows QPA, and reset does exactly what is necessary in this case.
-        qApp->inputMethod()->reset();
-#else
-        qApp->inputMethod()->commit();
-#endif
-    }
-
-    m_host->ForwardMouseEvent(webEvent);
+    handlePointerEvent<QMouseEvent>(event);
 }
 
 void RenderWidgetHostViewQt::handleKeyEvent(QKeyEvent *ev)
@@ -1483,6 +1447,59 @@ void RenderWidgetHostViewQt::handleTouchEvent(QTouchEvent *ev)
     }
 }
 
+void RenderWidgetHostViewQt::handleTabletEvent(QTabletEvent *event)
+{
+    handlePointerEvent<QTabletEvent>(event);
+}
+
+template<class T>
+void RenderWidgetHostViewQt::handlePointerEvent(T *event)
+{
+    // Currently WebMouseEvent is a subclass of WebPointerProperties, so basically
+    // tablet events are mouse events with extra properties.
+    blink::WebMouseEvent webEvent = WebEventFactory::toWebMouseEvent(event, dpiScale());
+    if ((webEvent.GetType() == blink::WebInputEvent::kMouseDown || webEvent.GetType() == blink::WebInputEvent::kMouseUp)
+            && webEvent.button == blink::WebMouseEvent::Button::kNoButton) {
+        // Blink can only handle the 3 main mouse-buttons and may assert when processing mouse-down for no button.
+        return;
+    }
+
+    if (webEvent.GetType() == blink::WebInputEvent::kMouseDown) {
+        if (event->button() != m_clickHelper.lastPressButton
+            || (event->timestamp() - m_clickHelper.lastPressTimestamp > static_cast<ulong>(qGuiApp->styleHints()->mouseDoubleClickInterval()))
+            || (event->pos() - m_clickHelper.lastPressPosition).manhattanLength() > qGuiApp->styleHints()->startDragDistance())
+            m_clickHelper.clickCounter = 0;
+
+        m_clickHelper.lastPressTimestamp = event->timestamp();
+        webEvent.click_count = ++m_clickHelper.clickCounter;
+        m_clickHelper.lastPressButton = event->button();
+        m_clickHelper.lastPressPosition = QPointF(event->pos()).toPoint();
+    }
+
+    webEvent.movement_x = event->globalX() - m_previousMousePosition.x();
+    webEvent.movement_y = event->globalY() - m_previousMousePosition.y();
+
+    if (IsMouseLocked())
+        QCursor::setPos(m_previousMousePosition);
+    else
+        m_previousMousePosition = event->globalPos();
+
+    if (m_imeInProgress && webEvent.GetType() == blink::WebInputEvent::kMouseDown) {
+        m_imeInProgress = false;
+        // Tell input method to commit the pre-edit string entered so far, and finish the
+        // composition operation.
+#ifdef Q_OS_WIN
+        // Yes the function name is counter-intuitive, but commit isn't actually implemented
+        // by the Windows QPA, and reset does exactly what is necessary in this case.
+        qApp->inputMethod()->reset();
+#else
+        qApp->inputMethod()->commit();
+#endif
+    }
+
+    m_host->ForwardMouseEvent(webEvent);
+}
+
 void RenderWidgetHostViewQt::handleHoverEvent(QHoverEvent *ev)
 {
     m_host->ForwardMouseEvent(WebEventFactory::toWebMouseEvent(ev, dpiScale()));
diff --git a/src/core/render_widget_host_view_qt.h b/src/core/render_widget_host_view_qt.h
index 7d32cc645..74f14d0d4 100644
--- a/src/core/render_widget_host_view_qt.h
+++ b/src/core/render_widget_host_view_qt.h
@@ -186,6 +186,7 @@ public:
     void handleKeyEvent(QKeyEvent*);
     void handleWheelEvent(QWheelEvent*);
     void handleTouchEvent(QTouchEvent*);
+    void handleTabletEvent(QTabletEvent *ev);
 #ifndef QT_NO_GESTURES
     void handleGestureEvent(QNativeGestureEvent *);
 #endif
@@ -194,6 +195,8 @@ public:
     void handleInputMethodEvent(QInputMethodEvent*);
     void handleInputMethodQueryEvent(QInputMethodQueryEvent*);
 
+    template<class T> void handlePointerEvent(T*);
+
 #if defined(OS_MACOSX)
     void SetActive(bool active) override { QT_NOT_YET_IMPLEMENTED }
     bool IsSpeaking() const override { QT_NOT_YET_IMPLEMENTED; return false; }
diff --git a/src/core/web_event_factory.cpp b/src/core/web_event_factory.cpp
index 18f8d393f..b785adec0 100644
--- a/src/core/web_event_factory.cpp
+++ b/src/core/web_event_factory.cpp
@@ -76,6 +76,7 @@
 #include <QKeyEvent>
 #include <QMouseEvent>
 #include <QStyleHints>
+#include <QTabletEvent>
 #include <QWheelEvent>
 
 using namespace blink;
@@ -1032,7 +1033,8 @@ static inline double currentTimeForEvent(const QInputEvent* event)
     return static_cast<double>(timer.elapsed()) / 1000;
 }
 
-static WebMouseEvent::Button mouseButtonForEvent(QMouseEvent *event)
+template<class T>
+static WebMouseEvent::Button mouseButtonForEvent(T *event)
 {
     if (event->button() == Qt::LeftButton)
         return WebMouseEvent::Button::kLeft;
@@ -1041,7 +1043,7 @@ static WebMouseEvent::Button mouseButtonForEvent(QMouseEvent *event)
     else if (event->button() == Qt::MidButton)
         return WebMouseEvent::Button::kMiddle;
 
-    if (event->type() != QEvent::MouseMove)
+    if (event->type() != QEvent::MouseMove && event->type() != QEvent::TabletMove)
         return WebMouseEvent::Button::kNoButton;
 
     // This is technically wrong, mouse move should always have ButtonNone,
@@ -1147,14 +1149,17 @@ static WebInputEvent::Type webEventTypeForEvent(const QEvent* event)
 {
     switch (event->type()) {
     case QEvent::MouseButtonPress:
+    case QEvent::TabletPress:
         return WebInputEvent::kMouseDown;
     case QEvent::MouseButtonRelease:
+    case QEvent::TabletRelease:
         return WebInputEvent::kMouseUp;
     case QEvent::Enter:
         return WebInputEvent::kMouseEnter;
     case QEvent::Leave:
         return WebInputEvent::kMouseLeave;
     case QEvent::MouseMove:
+    case QEvent::TabletMove:
         return WebInputEvent::kMouseMove;
     case QEvent::Wheel:
         return WebInputEvent::kMouseWheel;
@@ -1178,6 +1183,20 @@ static WebInputEvent::Type webEventTypeForEvent(const QEvent* event)
     }
 }
 
+static WebPointerProperties::PointerType pointerTypeForTabletEvent(const QTabletEvent *ev)
+{
+    switch (ev->pointerType()) {
+    case QTabletEvent::UnknownPointer:
+        return WebPointerProperties::PointerType::kUnknown;
+    case QTabletEvent::Pen:
+        return WebPointerProperties::PointerType::kPen;
+    case QTabletEvent::Eraser:
+        return WebPointerProperties::PointerType::kEraser;
+    default:
+        return WebPointerProperties::PointerType::kMouse;
+    }
+}
+
 WebMouseEvent WebEventFactory::toWebMouseEvent(QMouseEvent *ev, double dpiScale)
 {
     WebMouseEvent webKitEvent(webEventTypeForEvent(ev),
@@ -1188,7 +1207,7 @@ WebMouseEvent WebEventFactory::toWebMouseEvent(QMouseEvent *ev, double dpiScale)
                               modifiersForEvent(ev),
                               currentTimeForEvent(ev));
 
-    webKitEvent.button = mouseButtonForEvent(ev);
+    webKitEvent.button = mouseButtonForEvent<QMouseEvent>(ev);
     webKitEvent.click_count = 0;
 
     return webKitEvent;
@@ -1208,6 +1227,29 @@ WebMouseEvent WebEventFactory::toWebMouseEvent(QHoverEvent *ev, double dpiScale)
     return webKitEvent;
 }
 
+WebMouseEvent WebEventFactory::toWebMouseEvent(QTabletEvent *ev, double dpiScale)
+{
+    WebMouseEvent webKitEvent(webEventTypeForEvent(ev),
+                              ev->x() / dpiScale,
+                              ev->y() / dpiScale,
+                              ev->globalX(),
+                              ev->globalY(),
+                              modifiersForEvent(ev),
+                              currentTimeForEvent(ev));
+
+    webKitEvent.force = ev->pressure();
+    webKitEvent.tilt_x = ev->xTilt();
+    webKitEvent.tilt_y = ev->yTilt();
+    webKitEvent.tangential_pressure = ev->tangentialPressure();
+    webKitEvent.twist = ev->rotation();
+    webKitEvent.pointer_type = pointerTypeForTabletEvent(ev);
+
+    webKitEvent.button = mouseButtonForEvent<QTabletEvent>(ev);
+    webKitEvent.click_count = 0;
+
+    return webKitEvent;
+}
+
 #ifndef QT_NO_GESTURES
 WebGestureEvent WebEventFactory::toWebGestureEvent(QNativeGestureEvent *ev, double dpiScale)
 {
diff --git a/src/core/web_event_factory.h b/src/core/web_event_factory.h
index 259795c1f..c9ae86a73 100644
--- a/src/core/web_event_factory.h
+++ b/src/core/web_event_factory.h
@@ -53,6 +53,7 @@ QT_BEGIN_NAMESPACE
 class QHoverEvent;
 class QKeyEvent;
 class QMouseEvent;
+class QTabletEvent;
 class QWheelEvent;
 #ifndef QT_NO_GESTURES
 class QNativeGestureEvent;
@@ -64,6 +65,7 @@ class WebEventFactory {
 public:
     static blink::WebMouseEvent toWebMouseEvent(QMouseEvent*, double dpiScale);
     static blink::WebMouseEvent toWebMouseEvent(QHoverEvent*, double dpiScale);
+    static blink::WebMouseEvent toWebMouseEvent(QTabletEvent*, double dpiScale);
 #ifndef QT_NO_GESTURES
     static blink::WebGestureEvent toWebGestureEvent(QNativeGestureEvent *, double dpiScale);
 #endif
diff --git a/tests/manual/html/pointer-events.html b/tests/manual/html/pointer-events.html
new file mode 100644
index 000000000..c6e728662
--- /dev/null
+++ b/tests/manual/html/pointer-events.html
@@ -0,0 +1,69 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Pointer event test</title>
+  </head>
+  <body>
+
+<p>
+    <canvas id="listener" width="500" height="500" style="border: silver 1px dotted;"></canvas>
+</p>
+<p>
+    Touch this circle with a stylus. Its size indicates your pressure; its position is the angle between your stylus and your tablet device; and the radius is the rotation - if your tablet supports it.
+</p>
+
+  </body>
+  <script>
+
+var canvas = document.getElementById("listener");
+var context = canvas.getContext('2d');
+
+var eventName = [
+    "pointerover",
+    "pointerenter",
+    "pointerdown",
+    "pointermove",
+    "pointerup",
+    "pointercancel",
+    "pointerout",
+    "pointerleave",
+    "gotpointercapture",
+    "lostpointercapture"
+];
+
+for (var i = 0; i < eventName.length; i++) {
+    canvas.addEventListener(eventName[i], function(ev) {
+        drawCircle(ev.pressure, ev.tiltX, ev.tiltY, ev.twist);
+    }, false);
+}
+
+drawCircle(0, 0, 0, 0);
+
+function drawCircle(pressure, tiltX, tiltY, twist) {
+    var centerX = canvas.width / 2 + tiltX;
+    var centerY = canvas.height / 2 + tiltY;
+    var radius = 100 + 100 * pressure;
+
+    context.clearRect(0, 0, canvas.width, canvas.height);
+    context.beginPath();
+    context.arc(centerX,
+                centerY,
+                radius,
+                0,
+                2 * Math.PI,
+                false);
+    context.fillStyle = 'lightblue';
+    context.fill();
+    context.lineWidth = 3;
+    context.strokeStyle = '#008B8B';
+    context.stroke();
+
+    context.beginPath();
+    context.moveTo(centerX, centerY);
+    context.lineTo(centerX + radius * Math.cos(twist), centerY + radius * Math.sin(twist));
+    context.stroke();
+}
+
+</script>
+</html>