Add declarative QQuickTextMetrics API from QQuickFontMetrics invokables

This allows use of a declarative API for the functions in QFontMetricsF
which take parameters. This solves the problem of QML expressions that
use QML methods not being re-evaluated when the internal data changes,
by allowing the user to set the arguments as properties of a
TextMetrics object, that would otherwise have to be passed to QML
methods.

For example:

    FontMetrics {
        id: fontMetrics
    }

    property rect r: fontMetrics.boundingRect("Blah")

At some point, the font of the FontMetrics object is changed, but r
will still represent the original bounding rect. Instead, the user will
now write:

    TextMetrics {
        id: textMetrics
        text: "Blah"
    }

    property rect r: textMetrics.boundingRect

The QML methods remain in QQuickFontMetrics for those who need an
imperative API.

[ChangeLog][QtQuick] Added QQuickTextMetrics, which provides a
declarative API for the functions in QFontMetricsF which take
arguments.

Change-Id: I019dc4639531906fc751ba61281cc1c695742287
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>

1 files changed, 111 insertions, 0 deletions

diff --git a/src/quick/util/qquicktextmetrics_p.h b/src/quick/util/qquicktextmetrics_p.h
new file mode 100644
index 0000000000..ec993229e5
--- /dev/null
+++ b/src/quick/util/qquicktextmetrics_p.h
@@ -0,0 +1,111 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtQuick module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QQUICKTEXTMETRICS_H
+#define QQUICKTEXTMETRICS_H
+
+#include <qqml.h>
+
+#include <QtGui/QFontMetricsF>
+#include <QtCore/QObject>
+
+QT_BEGIN_NAMESPACE
+
+class QFont;
+
+class Q_AUTOTEST_EXPORT QQuickTextMetrics : public QObject
+{
+    Q_OBJECT
+
+    Q_PROPERTY(QFont font READ font WRITE setFont NOTIFY fontChanged FINAL)
+    Q_PROPERTY(QString text READ text WRITE setText NOTIFY textChanged FINAL)
+    Q_PROPERTY(qreal advanceWidth READ advanceWidth NOTIFY metricsChanged FINAL)
+    Q_PROPERTY(QRectF boundingRect READ boundingRect NOTIFY metricsChanged FINAL)
+    Q_PROPERTY(qreal width READ width NOTIFY metricsChanged FINAL)
+    Q_PROPERTY(qreal height READ height NOTIFY metricsChanged FINAL)
+    Q_PROPERTY(QRectF tightBoundingRect READ tightBoundingRect NOTIFY metricsChanged FINAL)
+    Q_PROPERTY(QString elidedText READ elidedText NOTIFY metricsChanged FINAL)
+    Q_PROPERTY(Qt::TextElideMode elide READ elide WRITE setElide NOTIFY elideChanged FINAL)
+    Q_PROPERTY(qreal elideWidth READ elideWidth WRITE setElideWidth NOTIFY elideWidthChanged FINAL)
+
+public:
+    explicit QQuickTextMetrics(QObject *parent = 0);
+    ~QQuickTextMetrics();
+
+    QFont font() const;
+    void setFont(const QFont &font);
+
+    QString text() const;
+    void setText(const QString &text);
+
+    Qt::TextElideMode elide() const;
+    void setElide(Qt::TextElideMode elide);
+
+    qreal elideWidth() const;
+    void setElideWidth(qreal elideWidth);
+
+    qreal advanceWidth() const;
+    QRectF boundingRect() const;
+    qreal width() const;
+    qreal height() const;
+    QRectF tightBoundingRect() const;
+    QString elidedText() const;
+
+Q_SIGNALS:
+    void fontChanged();
+    void textChanged();
+    void elideChanged();
+    void elideWidthChanged();
+    void metricsChanged();
+
+private:
+    QString m_text;
+    QFont m_font;
+    QFontMetricsF m_metrics;
+    Qt::TextElideMode m_elide;
+    qreal m_elideWidth;
+};
+
+QT_END_NAMESPACE
+
+QML_DECLARE_TYPE(QQuickTextMetrics)
+
+#endif // QQUICKTEXTMETRICS_H