Fix constness of QPaintDevice arguments

QFont, QFontMetrics, QFontMetricsF and QTextLayout constructors
use only const methods of QPaintDevice so there is no reason
for them to require a non-const pointer argument

Fixes: QTBUG-65967
Change-Id: Ibfcdef2a25f0cd4284dad76135fc4c9bf5667d7a
Reviewed-by: Samuel Gaist <samuel.gaist@idiap.ch>
Reviewed-by: Christian Ehrlicher <ch.ehrlicher@gmx.de>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

src/gui/text/qfont.cpp

@@ -562,14 +562,25 @@ QFontEngineData::~QFontEngineData()
     \since 5.2
 */
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
 /*!
+  \obsolete
   Constructs a font from \a font for use on the paint device \a pd.
 */
 QFont::QFont(const QFont &font, QPaintDevice *pd)
+    : QFont(font, static_cast<const QPaintDevice*>(pd))
+{}
+#endif
+
+/*!
+  \since 5.13
+  Constructs a font from \a font for use on the paint device \a pd.
+*/
+QFont::QFont(const QFont &font, const QPaintDevice *pd)
     : resolve_mask(font.resolve_mask)
 {
-    Q_ASSERT(pd != 0);
+    Q_ASSERT(pd);
-    int dpi = pd->logicalDpiY();
+    const int dpi = pd->logicalDpiY();
     const int screen = 0;
     if (font.d->dpi != dpi || font.d->screen != screen ) {
         d = new QFontPrivate(*font.d);

src/gui/text/qfont.h

@@ -170,8 +170,11 @@ public:
 
     QFont();
     QFont(const QString &family, int pointSize = -1, int weight = -1, bool italic = false);
-    QFont(const QFont &, QPaintDevice *pd);
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
-    QFont(const QFont &);
+    QFont(const QFont &font, QPaintDevice *pd);
+#endif
+    QFont(const QFont &font, const QPaintDevice *pd);
+    QFont(const QFont &font);
     ~QFont();
 
     void swap(QFont &other)

src/gui/text/qfontmetrics.cpp

@@ -156,6 +156,8 @@ QFontMetrics::QFontMetrics(const QFont &font)
 }
 
 /*!
+    \since 5.13
+    \fn QFontMetrics::QFontMetrics(const QFont &font, const QPaintDevice *paintdevice)
     Constructs a font metrics object for \a font and \a paintdevice.
 
     The font metrics will be compatible with the paintdevice passed.
@@ -168,9 +170,21 @@ QFontMetrics::QFontMetrics(const QFont &font)
     passed in the constructor at the time it is created, and is not
     updated if the font's attributes are changed later.
 */
+
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+/*!
+    \fn QFontMetrics::QFontMetrics(const QFont &font, QPaintDevice *paintdevice)
+    \obsolete
+    Identical to QFontMetrics::QFontMetrics(const QFont &font, const QPaintDevice *paintdevice)
+*/
+
+
 QFontMetrics::QFontMetrics(const QFont &font, QPaintDevice *paintdevice)
+#else
+QFontMetrics::QFontMetrics(const QFont &font, const QPaintDevice *paintdevice)
+#endif
 {
-    int dpi = paintdevice ? paintdevice->logicalDpiY() : qt_defaultDpi();
+    const int dpi = paintdevice ? paintdevice->logicalDpiY() : qt_defaultDpi();
     const int screen = 0;
     if (font.d->dpi != dpi || font.d->screen != screen ) {
         d = new QFontPrivate(*font.d);
@@ -1127,6 +1141,8 @@ QFontMetricsF::QFontMetricsF(const QFont &font)
 }
 
 /*!
+    \fn QFontMetricsF::QFontMetricsF(const QFont &font, const QPaintDevice *paintdevice)
+    \since 5.13
     Constructs a font metrics object for \a font and \a paintdevice.
 
     The font metrics will be compatible with the paintdevice passed.
@@ -1139,7 +1155,20 @@ QFontMetricsF::QFontMetricsF(const QFont &font)
     passed in the constructor at the time it is created, and is not
     updated if the font's attributes are changed later.
 */
+
+
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+/*!
+    \fn QFontMetricsF::QFontMetricsF(const QFont &font, QPaintDevice *paintdevice)
+    \obsolete
+    Identical to QFontMetricsF::QFontMetricsF(const QFont &font, const QPaintDevice *paintdevice)
+*/
+
+
 QFontMetricsF::QFontMetricsF(const QFont &font, QPaintDevice *paintdevice)
+#else
+QFontMetricsF::QFontMetricsF(const QFont &font, const QPaintDevice *paintdevice)
+#endif
 {
     int dpi = paintdevice ? paintdevice->logicalDpiY() : qt_defaultDpi();
     const int screen = 0;

src/gui/text/qfontmetrics.h

@@ -59,7 +59,19 @@ class Q_GUI_EXPORT QFontMetrics
 {
 public:
     explicit QFontMetrics(const QFont &);
-    QFontMetrics(const QFont &, QPaintDevice *pd);
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+    QFontMetrics(const QFont &font, QPaintDevice *pd);
+#ifndef Q_QDOC
+    // the template is necessary to make QFontMetrics(font,nullptr) and QFontMetrics(font,NULL)
+    // not ambiguous. Implementation detail that should not be documented.
+    template<char = 0>
+#endif
+    QFontMetrics(const QFont &font, const QPaintDevice *pd)
+        : QFontMetrics(font, const_cast<QPaintDevice*>(pd))
+    {}
+#else
+    QFontMetrics(const QFont &font, const QPaintDevice *pd);
+#endif
     QFontMetrics(const QFontMetrics &);
     ~QFontMetrics();
 
@@ -137,8 +149,20 @@ Q_DECLARE_SHARED(QFontMetrics)
 class Q_GUI_EXPORT QFontMetricsF
 {
 public:
-    explicit QFontMetricsF(const QFont &);
+    explicit QFontMetricsF(const QFont &font);
-    QFontMetricsF(const QFont &, QPaintDevice *pd);
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+    QFontMetricsF(const QFont &font, QPaintDevice *pd);
+#ifndef Q_QDOC
+    // the template is necessary to make QFontMetrics(font,nullptr) and QFontMetrics(font,NULL)
+    // not ambiguous. Implementation detail that should not be documented.
+    template<char = 0>
+#endif
+    QFontMetricsF(const QFont &font, const QPaintDevice *pd)
+        : QFontMetricsF(font, const_cast<QPaintDevice*>(pd))
+    {}
+#else
+    QFontMetricsF(const QFont &font, const QPaintDevice *pd);
+#endif
     QFontMetricsF(const QFontMetrics &);
     QFontMetricsF(const QFontMetricsF &);
     ~QFontMetricsF();

src/gui/text/qtextlayout.cpp

@@ -344,6 +344,8 @@ QTextLayout::QTextLayout(const QString& text)
 }
 
 /*!
+    \since 5.13
+    \fn QTextLayout::QTextLayout(const QString &text, const QFont &font, const QPaintDevice *paintdevice)
     Constructs a text layout to lay out the given \a text with the specified
     \a font.
 
@@ -351,11 +353,20 @@ QTextLayout::QTextLayout(const QString& text)
     the paint device, \a paintdevice. If \a paintdevice is 0 the
     calculations will be done in screen metrics.
 */
-QTextLayout::QTextLayout(const QString& text, const QFont &font, QPaintDevice *paintdevice)
+
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+/*!
+    \fn QTextLayout::QTextLayout(const QString &text, const QFont &font, QPaintDevice *paintdevice)
+    \obsolete
+    Identical to QTextLayout::QTextLayout(const QString &text, const QFont &font, const QPaintDevice *paintdevice)
+*/
+
+QTextLayout::QTextLayout(const QString &text, const QFont &font, QPaintDevice *paintdevice)
+#else
+QTextLayout::QTextLayout(const QString &text, const QFont &font, const QPaintDevice *paintdevice)
+#endif
 {
-    QFont f(font);
+    const QFont f(paintdevice ? QFont(font, paintdevice) : font);
-    if (paintdevice)
-        f = QFont(font, paintdevice);
     d = new QTextEngine((text.isNull() ? (const QString&)QString::fromLatin1("") : text), f);
 }
 

src/gui/text/qtextlayout.h

@@ -107,7 +107,19 @@ public:
     // does itemization
     QTextLayout();
     QTextLayout(const QString& text);
-    QTextLayout(const QString& text, const QFont &font, QPaintDevice *paintdevice = nullptr);
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+    QTextLayout(const QString &text, const QFont &font, QPaintDevice *paintdevice = nullptr);
+#ifndef Q_QDOC
+    // the template is necessary to make QTextLayout(font,text,nullptr) and QTextLayout(font,text,NULL)
+    // not ambiguous. Implementation detail that should not be documented.
+    template<char = 0>
+#endif
+    QTextLayout(const QString &text, const QFont &font, const QPaintDevice *paintdevice)
+        : QTextLayout(text, font, const_cast<QPaintDevice*>(paintdevice))
+    {}
+#else
+    QTextLayout(const QString &text, const QFont &font, const QPaintDevice *paintdevice = nullptr);
+#endif
     QTextLayout(const QTextBlock &b);
     ~QTextLayout();