Ref T220, font metric utility functions

Allows to obtain sizes based on number of characters

src/blackgui/guiutility.cpp

@@ -404,4 +404,47 @@ namespace BlackGui
         a->start(QPropertyAnimation::DeleteWhenStopped);
         return effect;
     }
+
+    QFontMetrics CGuiUtility::currentFontMetrics()
+    {
+        const QWidget *w = CGuiUtility::mainApplicationWindow();
+        if (w) { return w->fontMetrics(); }
+        return QApplication::fontMetrics();
+    }
+
+    QFont CGuiUtility::currentFont()
+    {
+        const QWidget *w = CGuiUtility::mainApplicationWindow();
+        if (w) { return w->font(); }
+        return QApplication::font();
+    }
+
+    QSize CGuiUtility::fontMetrics80Chars()
+    {
+        static const QString s("01234567890123456789012345678901234567890123456789012345678901234567890123456789");
+        const QFontMetrics fm = CGuiUtility::currentFontMetrics();
+        const int w = fm.width(s);
+        const int h = fm.height();
+        return QSize(w, h);
+    }
+
+    QSize CGuiUtility::fontMetricsLazyDog43Chars()
+    {
+        // 43 characters        0123456789012345678901234567890123456789012
+        static const QString s("The quick brown fox jumps over the lazy dog");
+        const QFontMetrics fm = CGuiUtility::currentFontMetrics();
+        const int w = fm.width(s);
+        const int h = fm.height();
+        return QSize(w, h);
+    }
+
+    QSize CGuiUtility::fontMetricsEstimateSize(int xCharacters, int yCharacters)
+    {
+        const QSize s1 = CGuiUtility::fontMetrics80Chars();
+        const QSize s2 = CGuiUtility::fontMetricsLazyDog43Chars();
+        const QSize s = s1 + s2;
+        const int w = s.width()  * xCharacters / 123;
+        const int h = s.height() * yCharacters / 2;
+        return QSize(w, h);
+    }
 } // ns

src/blackgui/guiutility.h

@@ -16,10 +16,13 @@
 #include "blackmisc/variant.h"
 
 #include <QByteArray>
+#include <QSize>
 #include <QPoint>
 #include <QString>
 #include <QWidget>
 #include <QWidgetList>
+#include <QFont>
+#include <QFontMetrics>
 #include <QModelIndexList>
 
 class QCheckBox;
@@ -131,6 +134,21 @@ namespace BlackGui
         //! Fade out a widget
         static QGraphicsOpacityEffect *fadeOutWidget(int durationMs, QWidget *widget, double startValue = 1.0, double endValue = 0.0);
 
+        //! Main window font metrics or default metrics
+        static QFontMetrics currentFontMetrics();
+
+        //! Main window font or default font
+        static QFont currentFont();
+
+        //! 80 characters width/height
+        static QSize fontMetrics80Chars();
+
+        //! 43 characters width/height "the quick brown ..."
+        static QSize fontMetricsLazyDog43Chars();
+
+        //! Estimate size based on current font
+        static QSize fontMetricsEstimateSize(int xCharacters, int yCharacters);
+
     private:
         //! Constructor, use static methods only
         CGuiUtility() {}