Add fontInfo property to Text

This provides a way to determine which font will actually be
used to presenting the text, which can be especially useful when
not using a fixed size font (the font info will then expose the
actual font size used by the Text element.)

[ChangeLog][QtQuick][Text] Added fontInfo property to Text type,
providing a way to query properties of the actual font used
for presenting the text.

Task-number: QTBUG-51133
Change-Id: I5860fb1bd25ac5734713f49c8482428f2d531d22
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Robin Burchell <robin.burchell@crimson.no>

src/quick/items/qquicktext.cpp

@@ -74,7 +74,7 @@ Q_DECLARE_LOGGING_CATEGORY(DBG_HOVER_TRACE)
 const QChar QQuickTextPrivate::elideChar = QChar(0x2026);
 
 QQuickTextPrivate::QQuickTextPrivate()
-    : elideLayout(0), textLine(0), lineWidth(0)
+    : fontInfo(font), elideLayout(0), textLine(0), lineWidth(0)
     , color(0xFF000000), linkColor(0xFF0000FF), styleColor(0xFF000000)
     , lineCount(1), multilengthEos(-1)
     , elideMode(QQuickText::ElideNone), hAlign(QQuickText::AlignLeft), vAlign(QQuickText::AlignTop)
@@ -1018,6 +1018,17 @@ QRectF QQuickTextPrivate::setupTextLayout(qreal *const baseline)
     implicitWidthValid = true;
     implicitHeightValid = true;
 
+    QFontInfo scaledFontInfo(scaledFont);
+    if (fontInfo.weight() != scaledFontInfo.weight()
+            || fontInfo.pixelSize() != scaledFontInfo.pixelSize()
+            || fontInfo.italic() != scaledFontInfo.italic()
+            || !qFuzzyCompare(fontInfo.pointSizeF(), scaledFontInfo.pointSizeF())
+            || fontInfo.family() != scaledFontInfo.family()
+            || fontInfo.styleName() != scaledFontInfo.styleName()) {
+        fontInfo = scaledFontInfo;
+        emit q->fontInfoChanged();
+    }
+
     if (eos != multilengthEos)
         truncated = true;
 
@@ -2974,4 +2985,80 @@ void QQuickText::resetBottomPadding()
     d->setBottomPadding(0, true);
 }
 
+/*!
+    \qmlproperty string QtQuick::Text::fontInfo.family
+    \since 5.9
+
+    The family name of the font that has been resolved for the current font
+    and fontSizeMode.
+*/
+
+/*!
+    \qmlproperty string QtQuick::Text::fontInfo.styleName
+    \since 5.9
+
+    The style name of the font info that has been resolved for the current font
+    and fontSizeMode.
+*/
+
+/*!
+    \qmlproperty bool QtQuick::Text::fontInfo.bold
+    \since 5.9
+
+    The bold state of the font info that has been resolved for the current font
+    and fontSizeMode. This is true if the weight of the resolved font is bold or higher.
+*/
+
+/*!
+    \qmlproperty int QtQuick::Text::fontInfo.weight
+    \since 5.9
+
+    The weight of the font info that has been resolved for the current font
+    and fontSizeMode.
+*/
+
+/*!
+    \qmlproperty bool QtQuick::Text::fontInfo.italic
+    \since 5.9
+
+    The italic state of the font info that has been resolved for the current font
+    and fontSizeMode.
+*/
+
+/*!
+    \qmlproperty real QtQuick::Text::fontInfo.pointSize
+    \since 5.9
+
+    The pointSize of the font info that has been resolved for the current font
+    and fontSizeMode.
+*/
+
+/*!
+    \qmlproperty string QtQuick::Text::fontInfo.pixelSize
+    \since 5.9
+
+    The pixel size of the font info that has been resolved for the current font
+    and fontSizeMode.
+*/
+QJSValue QQuickText::fontInfo() const
+{
+    Q_D(const QQuickText);
+
+    QJSEngine *engine = qjsEngine(this);
+    if (!engine) {
+        qmlWarning(this) << "fontInfo: item has no JS engine";
+        return QJSValue();
+    }
+
+    QJSValue value = engine->newObject();
+    value.setProperty(QStringLiteral("family"), d->fontInfo.family());
+    value.setProperty(QStringLiteral("styleName"), d->fontInfo.styleName());
+    value.setProperty(QStringLiteral("bold"), d->fontInfo.bold());
+    value.setProperty(QStringLiteral("weight"), d->fontInfo.weight());
+    value.setProperty(QStringLiteral("italic"), d->fontInfo.italic());
+    value.setProperty(QStringLiteral("pointSize"), d->fontInfo.pointSizeF());
+    value.setProperty(QStringLiteral("pixelSize"), d->fontInfo.pixelSize());
+    return value;
+}
+
 QT_END_NAMESPACE

src/quick/items/qquicktext_p.h

@@ -98,6 +98,8 @@ class Q_QUICK_PRIVATE_EXPORT QQuickText : public QQuickImplicitSizeItem
     Q_PROPERTY(qreal rightPadding READ rightPadding WRITE setRightPadding RESET resetRightPadding NOTIFY rightPaddingChanged REVISION 6)
     Q_PROPERTY(qreal bottomPadding READ bottomPadding WRITE setBottomPadding RESET resetBottomPadding NOTIFY bottomPaddingChanged REVISION 6)
 
+    Q_PROPERTY(QJSValue fontInfo READ fontInfo NOTIFY fontInfoChanged REVISION 9)
+
 public:
     QQuickText(QQuickItem *parent=0);
     ~QQuickText();
@@ -248,6 +250,8 @@ public:
     void setBottomPadding(qreal padding);
     void resetBottomPadding();
 
+    QJSValue fontInfo() const;
+
 Q_SIGNALS:
     void textChanged(const QString &text);
     void linkActivated(const QString &link);
@@ -280,6 +284,7 @@ Q_SIGNALS:
     Q_REVISION(6) void leftPaddingChanged();
     Q_REVISION(6) void rightPaddingChanged();
     Q_REVISION(6) void bottomPaddingChanged();
+    Q_REVISION(9) void fontInfoChanged();
 
 protected:
     QQuickText(QQuickTextPrivate &dd, QQuickItem *parent = 0);

src/quick/items/qquicktext_p_p.h

@@ -122,6 +122,7 @@ public:
     QString text;
     QFont font;
     QFont sourceFont;
+    QFontInfo fontInfo;
 
     QTextLayout layout;
     QTextLayout *elideLayout;

tests/auto/quick/qquicktext/data/fontInfo.qml

@@ -0,0 +1,24 @@
+import QtQuick 2.9
+
+Item {
+    Text {
+        id: main
+        objectName: "main"
+        width: 500
+        height: 500
+        text: "Meaningless text"
+        font.pixelSize: 1000
+        fontSizeMode: Text.Fit
+    }
+
+    Text {
+        objectName: "copy"
+        text: main.text
+        width: main.width
+        height: main.height
+
+        font.family: main.fontInfo.family
+        font.pixelSize: main.fontInfo.pixelSize
+    }
+}
+

tests/auto/quick/qquicktext/tst_qquicktext.cpp

@@ -154,6 +154,8 @@ private slots:
     void hAlignWidthDependsOnImplicitWidth_data();
     void hAlignWidthDependsOnImplicitWidth();
 
+    void fontInfo();
+
 private:
     QStringList standard;
     QStringList richText;
@@ -4253,6 +4255,23 @@ void tst_qquicktext::hAlignWidthDependsOnImplicitWidth()
     QCOMPARE(numberOfNonWhitePixels(0, rectX - 1, image), 0);
 }
 
+void tst_qquicktext::fontInfo()
+{
+    QQmlComponent component(&engine, testFile("fontInfo.qml"));
+
+    QScopedPointer<QObject> object(component.create());
+    QObject *root = object.data();
+
+    QQuickText *main = root->findChild<QQuickText *>("main");
+    QVERIFY(main);
+    QCOMPARE(main->font().pixelSize(), 1000);
+
+    QQuickText *copy = root->findChild<QQuickText *>("copy");
+    QVERIFY(copy);
+    QCOMPARE(copy->font().family(), QFontInfo(QFont()).family());
+    QVERIFY(copy->font().pixelSize() < 1000);
+}
+
 QTEST_MAIN(tst_qquicktext)
 
 #include "tst_qquicktext.moc"