Implemented scaling of KCalcDisplay on resize

kcalc.cpp

@@ -2687,6 +2687,7 @@ int main(int argc, char *argv[])
                         QStringLiteral("ochominutosdearco@yahoo.es"));
     aboutData.addAuthor(i18n("Michel Marti"), QString(), QStringLiteral("mma@objectxp.com"));
     aboutData.addAuthor(i18n("David Johnson"), QString(), QStringLiteral("david@usermode.org"));
+    aboutData.addAuthor(i18n("Niklas Freund"), QString(), QStringLiteral("nalquas.dev@gmail.com"));
 
     KAboutData::setApplicationData(aboutData);
     app.setWindowIcon(QIcon::fromTheme(QStringLiteral("accessories-calculator"), app.windowIcon()));

kcalc.h

@@ -106,6 +106,9 @@ public:
 
     Q_DECLARE_FLAGS(UpdateFlags, UpdateFlag)
 
+protected:
+    void resizeEvent(QResizeEvent* event) override;
+    
 private:
     bool eventFilter(QObject *o, QEvent *e) override;
     bool event(QEvent *e) override;
@@ -126,8 +129,6 @@ private:
     void setAngle();
     void setBase();
 
-    void resizeEvent(QResizeEvent* event) override;
-
     void updateDisplay(UpdateFlags flags);
     void updateHistoryWithFunction(CalcEngine::Operation);
     KCalcStatusBar *statusBar();

kcalc.ui

@@ -24,11 +24,11 @@
     <enum>QLayout::SetMinimumSize</enum>
    </property>
    <item>
-    <layout class="QVBoxLayout" name="firstVerticalLayout">
+    <layout class="QVBoxLayout" name="firstVerticalLayout" stretch="1,1,0,3">
      <item>
       <widget class="KCalcDisplay" name="calc_display">
        <property name="sizePolicy">
-        <sizepolicy hsizetype="MinimumExpanding" vsizetype="Fixed">
+        <sizepolicy hsizetype="MinimumExpanding" vsizetype="MinimumExpanding">
          <horstretch>0</horstretch>
          <verstretch>0</verstretch>
         </sizepolicy>

kcalcdisplay.cpp

@@ -598,6 +598,26 @@ void KCalcDisplay::setText(const QString &string)
     Q_EMIT changedText(text_);
 }
 
+//------------------------------------------------------------------------------
+// Name: setFont
+// Desc: Set the font and recalculate the font size to better fit
+//------------------------------------------------------------------------------
+void KCalcDisplay::setFont(const QFont &font)
+{
+    // Make a copy of the font
+    QFont* newFont = new QFont(font);
+    
+    // Calculate ideal font size
+    // constant arbitrarily chosen, adjust/increase if scaling issues arise
+    newFont->setPointSizeF(qMax(double(font.pointSize()), contentsRect().height() / 3.6));
+    
+    // Apply font
+    QFrame::setFont(*newFont);
+    
+    // Free the memory
+    delete newFont;
+}
+
 //------------------------------------------------------------------------------
 // Name: formatDecimalNumber
 // Desc: Convert decimal number to locale-dependent format.
@@ -1025,7 +1045,7 @@ void KCalcDisplay::paintEvent(QPaintEvent *)
     // draw the status texts using half of the normal
     // font size but not smaller than 7pt
     QFont fnt(font());
-    fnt.setPointSize(qMax((fnt.pointSize() / 2), 7));
+    fnt.setPointSizeF(qMax((fnt.pointSize() / 2.0), 7.0));
     painter.setFont(fnt);
 
     QFontMetrics fm(fnt);
@@ -1037,6 +1057,18 @@ void KCalcDisplay::paintEvent(QPaintEvent *)
     }
 }
 
+//------------------------------------------------------------------------------
+// Name: resizeEvent
+// Desc: resize display and adjust font size
+//------------------------------------------------------------------------------
+void KCalcDisplay::resizeEvent(QResizeEvent* event)
+{
+    QFrame::resizeEvent(event);
+
+    // Set font again (forcing size recalculation)
+    setFont(KCalcSettings::displayFont());
+}
+
 //------------------------------------------------------------------------------
 // Name: sizeHint
 // Desc:

kcalcdisplay.h

@@ -65,6 +65,7 @@ public:
     void setFixedPrecision(int precision);
     void setPrecision(int precision);
     void setText(const QString &string);
+    void setFont(const QFont &font);
     QString formatDecimalNumber(QString string);
     QString groupDigits(const QString &displayString, int numDigits);
     QString text() const;
@@ -89,6 +90,7 @@ Q_SIGNALS:
 protected:
     void mousePressEvent(QMouseEvent *) override;
     void paintEvent(QPaintEvent *p) override;
+    void resizeEvent(QResizeEvent* event) override;
 
 private:
     bool changeSign();