Added KCalcHistory font scaling support

kcalcdisplay.cpp

@@ -38,8 +38,6 @@ KCalcDisplay::KCalcDisplay(QWidget *parent)
     , history_index_(0)
     , selection_timer_(new QTimer(this))
 {
-    baseFont_ = nullptr;
-    
     setFocusPolicy(Qt::StrongFocus);
 
     setSizePolicy(QSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed));

kcalcdisplay.h

@@ -122,7 +122,7 @@ private:
 
     KNumber display_amount_;
     
-    QFont* baseFont_;
+    QFont* baseFont_ = nullptr;
 
     QVector<KNumber> history_list_;
     int history_index_;

kcalchistory.cpp

@@ -32,19 +32,19 @@ KCalcHistory::~KCalcHistory()
 //------------------------------------------------------------------------------
 void KCalcHistory::addToHistory(const QString &str, bool set_new_line_)
 {
-    // add_new_line is false on launch and after clearHistory()
+    // add_new_line_ is false on launch and after clearHistory()
     // so the first line doesn't get an unnecessary new line
-    if (add_new_line) {
+    if (add_new_line_) {
         insertHtml(QStringLiteral("<br>"));
         moveCursor(QTextCursor::Start);
-        add_new_line = false;
+        add_new_line_ = false;
     }
 
     insertHtml(str);
 
     if (set_new_line_) {
         moveCursor(QTextCursor::Start);
-        add_new_line = true;
+        add_new_line_ = true;
     }
 
     setAlignment(Qt::AlignRight);
@@ -119,9 +119,13 @@ void KCalcHistory::addFuncToHistory(const QString &func)
 void KCalcHistory::clearHistory()
 {
     clear();
-    add_new_line = false;
+    add_new_line_ = false;
 }
 
+//------------------------------------------------------------------------------
+// Name: changeSettings
+// Desc:
+//------------------------------------------------------------------------------
 void KCalcHistory::changeSettings()
 {
     QPalette pal = palette();
@@ -133,3 +137,59 @@ void KCalcHistory::changeSettings()
 
     setFont(KCalcSettings::historyFont());
 }
+
+//------------------------------------------------------------------------------
+// Name: setFont
+// Desc: Set the base font and recalculate the font size to better fit
+//------------------------------------------------------------------------------
+void KCalcHistory::setFont(const QFont &font)
+{
+    // Overwrite current baseFont
+    if (baseFont_) {
+        delete baseFont_;
+    }
+    baseFont_ = new QFont(font);
+    
+    updateFont();
+}
+
+//------------------------------------------------------------------------------
+// Name: updateFont
+// Desc: Update font using baseFont to better fit
+//------------------------------------------------------------------------------
+void KCalcHistory::updateFont()
+{
+    // Make a working copy of the font
+    QFont* newFont = new QFont(baseFont());
+    
+    // Calculate ideal font size based on width, using historyFont as minimum size
+    // constant arbitrarily chosen: 252 is min content width. 252/x = 10pt. Thus, x = 252/10 = 25.2
+    newFont->setPointSizeF(qMax(double(baseFont().pointSizeF()), contentsRect().width() / 25.2));
+    
+    // Apply font
+    QTextEdit::setFont(*newFont);
+    
+    // Free the memory
+    delete newFont;
+}
+
+//------------------------------------------------------------------------------
+// Name: baseFont
+// Desc:
+//------------------------------------------------------------------------------
+const QFont& KCalcHistory::baseFont() const
+{
+    return *baseFont_;
+}
+
+//------------------------------------------------------------------------------
+// Name: resizeEvent
+// Desc: resize history and adjust font size
+//------------------------------------------------------------------------------
+void KCalcHistory::resizeEvent(QResizeEvent* event)
+{
+    QTextEdit::resizeEvent(event);
+
+    // Update font size
+    updateFont();
+}

kcalchistory.h

@@ -29,12 +29,19 @@ public:
     void addFuncToHistory(const QString &);
 
     void changeSettings();
+    void setFont(const QFont &font);
+    const QFont &baseFont() const;
 
 public Q_SLOTS:
     void clearHistory();
 
+protected:
+    void resizeEvent(QResizeEvent* event) override;
+
 private:
-    bool add_new_line = false;
+    bool add_new_line_ = false;
+    QFont* baseFont_ = nullptr;
+    void updateFont();
 };
 
 #endif