qt: Replace functions deprecated in Qt 5.13

[hebasto]

The following functions are obsolete in Qt 5.13:

• QFontMetrics::width()
• QDesktopWidget::availableGeometry()
• QDesktopWidget::screenGeometry()

This PR replaces them and does not change behavior.

Here are some excerpts from the master build log:

qt/bitcoingui.cpp: In constructor ‘BitcoinGUI::BitcoinGUI(interfaces::Node&, const PlatformStyle*, const NetworkStyle*, QWidget*)’:
qt/bitcoingui.cpp:84:57: warning: ‘const QRect QDesktopWidget::availableGeometry(int) const’ is deprecated: Use QGuiApplication::screens() [-Wdeprecated-declarations]
         move(QApplication::desktop()->availableGeometry().center() - frameGeometry().center());
                                                         ^
In file included from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/QDesktopWidget:1:0,
                 from qt/bitcoingui.cpp:43:
/home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/qdesktopwidget.h:88:67: note: declared here
     QT_DEPRECATED_X("Use QGuiApplication::screens()") const QRect availableGeometry(int screen = -1) const;
                                                                   ^~~~~~~~~~~~~~~~~

qt/bitcoingui.cpp:1410:74: warning: ‘int QFontMetrics::width(const QString&, int) const’ is deprecated: Use QFontMetrics::horizontalAdvance [-Wdeprecated-declarations]
         max_width = qMax(max_width, fm.width(BitcoinUnits::longName(unit)));
                                                                          ^
In file included from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/qwidget.h:50:0,
                 from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/qdialog.h:44,
                 from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/QDialog:1,
                 from ./qt/optionsdialog.h:8,
                 from ./qt/bitcoingui.h:12,
                 from qt/bitcoingui.cpp:5:
/home/hebasto/Qt/5.13.0/gcc_64/include/QtGui/qfontmetrics.h:108:9: note: declared here
     int width(const QString &, int len = -1) const;
         ^~~~~

qt/splashscreen.cpp: In constructor ‘SplashScreen::SplashScreen(interfaces::Node&, Qt::WindowFlags, const NetworkStyle*)’:
qt/splashscreen.cpp:127:50: warning: ‘const QRect QDesktopWidget::screenGeometry(int) const’ is deprecated: Use QGuiApplication::screens() [-Wdeprecated-declarations]
     move(QApplication::desktop()->screenGeometry().center() - r.center());
                                                  ^
In file included from /home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/QDesktopWidget:1:0,
                 from qt/splashscreen.cpp:24:
/home/hebasto/Qt/5.13.0/gcc_64/include/QtWidgets/qdesktopwidget.h:79:67: note: declared here
     QT_DEPRECATED_X("Use QGuiApplication::screens()") const QRect screenGeometry(int screen = -1) const;
                                                                    ^~~~~~~~~~~~~~

[DrahtBot]

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Conflicts

Reviewers, this pull request conflicts with the following ones:

• #15768 (gui: Add close window shortcut by IPGlider)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

[jonatack]

Concept ACK, saw these warnings just now while building with Qt 5.13.0 on macOS.

[promag]

1260ecd

Isn't it better to use a deprecated function instead of implementing workarounds? IMHO deprecated stuff can be removed only when it's 1-to-1. So in this case this change sounds premature.

[hebasto]

IMHO deprecated stuff can be removed only when it's 1-to-1.

Unfortunately, Qt's "support version window" (for the mentioned feature), i.e., 5.11 to 5.13, is narrower than ours, i.e., 5.5.1 to 5.13.

[jonasschnelli]

utACK c6dd32d

Abstracting it into our helper layer seems a good approach.

[laanwj]

I think qt is over-zealous here with renaming, but that's not our fault, utACK c6dd32d