Add support for ImhAnchorRectangle

Adds the following API:

 * QInputMethod::anchorRectangle()
 * QPlatformInputContext::setSelectionOnFocusObject()

This will be used for determining how to display selection handles.

Change-Id: If57e3fd58ff0f1ba7899f7dd62bfa9c006028667
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@theqtcompany.com>

src/corelib/global/qnamespace.h

@@ -1338,6 +1338,7 @@ public:
         ImTextBeforeCursor = 0x800,
         ImTextAfterCursor = 0x1000,
         ImEnterKeyType = 0x2000,
+        ImAnchorRectangle = 0x4000,
 
         ImPlatformData = 0x80000000,
         ImQueryInput = ImCursorRectangle | ImCursorPosition | ImSurroundingText |

src/gui/kernel/qinputmethod.cpp

@@ -97,6 +97,7 @@ void QInputMethod::setInputItemTransform(const QTransform &transform)
 
     d->inputItemTransform = transform;
     emit cursorRectangleChanged();
+    emit anchorRectangleChanged();
 }
 
 
@@ -126,6 +127,19 @@ void QInputMethod::setInputItemRectangle(const QRectF &rect)
     d->inputRectangle = rect;
 }
 
+static QRectF inputMethodQueryRectangle_helper(Qt::InputMethodQuery imquery, const QTransform &xform)
+{
+    QRectF r;
+    if (QObject *focusObject = qGuiApp->focusObject()) {
+        QInputMethodQueryEvent query(imquery);
+        QGuiApplication::sendEvent(focusObject, &query);
+        r = query.value(imquery).toRectF();
+        if (r.isValid())
+            r = xform.mapRect(r);
+    }
+    return r;
+}
+
 /*!
     \property QInputMethod::cursorRectangle
     \brief Input item's cursor rectangle in window coordinates.
@@ -136,18 +150,20 @@ void QInputMethod::setInputItemRectangle(const QRectF &rect)
 QRectF QInputMethod::cursorRectangle() const
 {
     Q_D(const QInputMethod);
+    return inputMethodQueryRectangle_helper(Qt::ImCursorRectangle, d->inputItemTransform);
+}
 
-    QObject *focusObject = qGuiApp->focusObject();
-    if (!focusObject)
-        return QRectF();
+/*!
+    \property QInputMethod::anchorRectangle
+    \brief Input item's anchor rectangle in window coordinates.
 
-    QInputMethodQueryEvent query(Qt::ImCursorRectangle);
-    QGuiApplication::sendEvent(focusObject, &query);
-    QRectF r = query.value(Qt::ImCursorRectangle).toRectF();
-    if (!r.isValid())
-        return QRectF();
-
-    return d->inputItemTransform.mapRect(r);
+    Anchor rectangle is often used by various text editing controls
+    like text prediction popups for following the text selection.
+*/
+QRectF QInputMethod::anchorRectangle() const
+{
+    Q_D(const QInputMethod);
+    return inputMethodQueryRectangle_helper(Qt::ImAnchorRectangle, d->inputItemTransform);
 }
 
 /*!
@@ -300,6 +316,10 @@ void QInputMethod::update(Qt::InputMethodQueries queries)
 
     if (queries & Qt::ImCursorRectangle)
         emit cursorRectangleChanged();
+
+    if (queries & (Qt::ImAnchorRectangle))
+        emit anchorRectangleChanged();
+
 }
 
 /*!

src/gui/kernel/qinputmethod.h

@@ -55,6 +55,7 @@ class Q_GUI_EXPORT QInputMethod : public QObject
     Q_OBJECT
     Q_DECLARE_PRIVATE(QInputMethod)
     Q_PROPERTY(QRectF cursorRectangle READ cursorRectangle NOTIFY cursorRectangleChanged)
+    Q_PROPERTY(QRectF anchorRectangle READ anchorRectangle NOTIFY anchorRectangleChanged)
     Q_PROPERTY(QRectF keyboardRectangle READ keyboardRectangle NOTIFY keyboardRectangleChanged)
     Q_PROPERTY(bool visible READ isVisible NOTIFY visibleChanged)
     Q_PROPERTY(bool animating READ isAnimating NOTIFY animatingChanged)
@@ -70,6 +71,7 @@ public:
 
     // in window coordinates
     QRectF cursorRectangle() const; // ### what if we have rotations for the item?
+    QRectF anchorRectangle() const; // ### ditto
 
     // keyboard geometry in window coords
     QRectF keyboardRectangle() const;
@@ -102,6 +104,7 @@ public Q_SLOTS:
 
 Q_SIGNALS:
     void cursorRectangleChanged();
+    void anchorRectangleChanged();
     void keyboardRectangleChanged();
     void visibleChanged();
     void animatingChanged();

src/gui/kernel/qplatforminputcontext.cpp

@@ -43,6 +43,8 @@
 #include "private/qkeymapper_p.h"
 #include <qpa/qplatforminputcontext_p.h>
 
+#include <QtGui/qtransform.h>
+
 QT_BEGIN_NAMESPACE
 
 /*!
@@ -267,5 +269,30 @@ void QPlatformInputContextPrivate::setInputMethodAccepted(bool accepted)
     QPlatformInputContextPrivate::s_inputMethodAccepted = accepted;
 }
 
+/*!
+ * \brief QPlatformInputContext::setSelectionOnFocusObject
+ * \param anchorPos Beginning of selection in currently active window coordinates
+ * \param cursorPos End of selection in currently active window coordinates
+ */
+void QPlatformInputContext::setSelectionOnFocusObject(const QPointF &anchorPos, const QPointF &cursorPos)
+{
+    QObject *focus = qApp->focusObject();
+    if (!focus)
+        return;
+
+    QInputMethod *im = QGuiApplication::inputMethod();
+    const QTransform mapToLocal = im->inputItemTransform().inverted();
+    bool success;
+    int anchor = QInputMethod::queryFocusObject(Qt::ImCursorPosition, anchorPos * mapToLocal).toInt(&success);
+    if (success) {
+        int cursor = QInputMethod::queryFocusObject(Qt::ImCursorPosition, cursorPos * mapToLocal).toInt(&success);
+        if (success) {
+            QList<QInputMethodEvent::Attribute> imAttributes;
+            imAttributes.append(QInputMethodEvent::Attribute(QInputMethodEvent::Selection, anchor, cursor - anchor, QVariant()));
+            QInputMethodEvent event(QString(), imAttributes);
+            QGuiApplication::sendEvent(focus, &event);
+        }
+    }
+}
 
 QT_END_NAMESPACE

src/gui/kernel/qplatforminputcontext.h

@@ -95,6 +95,8 @@ public:
     virtual void setFocusObject(QObject *object);
     bool inputMethodAccepted() const;
 
+    static void setSelectionOnFocusObject(const QPointF &anchorPos, const QPointF &cursorPos);
+
 private:
     friend class QGuiApplication;
     friend class QGuiApplicationPrivate;