Add detail pane font size option & refactor font size code

OnChange event handler for font size combo boxes is now shared
between the two. This required that current font size was store in
each combo box's Tag property rather than in separate field of
frame.

Author: delphidabbler

Src/FrDisplayPrefs.dfm

@@ -40,6 +40,14 @@ inherited DisplayPrefsFrame: TDisplayPrefsFrame
     Caption = 'Overview tree view &font size: '
     FocusControl = cbOverviewFontSize
   end
+  object lblDetailFontSize: TLabel
+    Left = 16
+    Top = 232
+    Width = 105
+    Height = 13
+    Caption = 'Detail pane font si&ze: '
+    FocusControl = cbDetailFontSize
+  end
   object cbOverviewTree: TComboBox
     Left = 192
     Top = 2
@@ -80,6 +88,14 @@ inherited DisplayPrefsFrame: TDisplayPrefsFrame
     Width = 57
     Height = 21
     TabOrder = 4
-    OnChange = cbOverviewFontSizeChange
+    OnChange = FontSizeChange
+  end
+  object cbDetailFontSize: TComboBox
+    Left = 192
+    Top = 229
+    Width = 57
+    Height = 21
+    TabOrder = 5
+    OnChange = FontSizeChange
   end
 end

Src/FrDisplayPrefs.pas

@@ -37,14 +37,15 @@   TDisplayPrefsFrame = class(TPrefsBaseFrame)
     lblSourceBGColour: TLabel;
     lblOverviewFontSize: TLabel;
     cbOverviewFontSize: TComboBox;
+    lblDetailFontSize: TLabel;
+    cbDetailFontSize: TComboBox;
     procedure chkHideEmptySectionsClick(Sender: TObject);
     procedure btnDefColoursClick(Sender: TObject);
-    procedure cbOverviewFontSizeChange(Sender: TObject);
+    procedure FontSizeChange(Sender: TObject);
   strict private
     var
       ///  <summary>Flag indicating if changes affect UI.</summary>
       fUIChanged: Boolean;
-      fOverviewFontSize: Integer;
       fMainColourBox: TColorBoxEx;
       fMainColourDlg: TColorDialogEx;
       fUserColourBox: TColorBoxEx;
@@ -63,7 +64,7 @@   TDisplayPrefsFrame = class(TPrefsBaseFrame)
     function CreateCustomColourBox(const ColourDlg: TColorDialogEx):
       TColorBoxEx;
     procedure ColourBoxChangeHandler(Sender: TObject);
-    procedure PopulateFontSizeCombo;
+    procedure PopulateFontSizeCombos;
   public
     constructor Create(AOwner: TComponent); override;
       {Class constructor. Sets up frame and populates controls.
@@ -137,8 +138,10 @@ procedure TDisplayPrefsFrame.Activate(const Prefs: IPreferences;
   Prefs.DBHeadingCustomColours[False].CopyTo(fMainColourDlg.CustomColors, True);
   Prefs.DBHeadingCustomColours[True].CopyTo(fUserColourDlg.CustomColors, True);
   Prefs.SourceCodeBGCustomColours.CopyTo(fSourceBGColourDlg.CustomColors, True);
-  fOverviewFontSize := Prefs.OverviewFontSize;
-  cbOverviewFontSize.Text := IntToStr(fOverviewFontSize);
+  cbOverviewFontSize.Tag := Prefs.OverviewFontSize; // store font size in .Tag
+  cbOverviewFontSize.Text := IntToStr(Prefs.OverviewFontSize);
+  cbDetailFontSize.Tag := Prefs.DetailFontSize;     // store font size in .Tag
+  cbDetailFontSize.Text := IntToStr(Prefs.DetailFontSize);
 end;
 
 procedure TDisplayPrefsFrame.ArrangeControls;
@@ -149,14 +152,14 @@ procedure TDisplayPrefsFrame.ArrangeControls;
     [
       lblOverviewTree, chkHideEmptySections, chkSnippetsInNewTab,
       lblMainColour, lblUserColour, lblSourceBGColour, btnDefColours,
-      lblOverviewFontSize
+      lblOverviewFontSize, lblDetailFontSize
     ],
     0
   );
   TCtrlArranger.AlignLefts(
     [
       cbOverviewTree, fMainColourBox, fUserColourBox, fSourceBGColourBox,
-      cbOverviewFontSize
+      cbOverviewFontSize, cbDetailFontSize
     ],
     TCtrlArranger.RightOf(
       [lblOverviewTree, lblMainColour, lblUserColour, lblSourceBGColour],
@@ -165,11 +168,11 @@ procedure TDisplayPrefsFrame.ArrangeControls;
   );
   TCtrlArranger.AlignVCentres(3, [lblOverviewTree, cbOverviewTree]);
   TCtrlArranger.MoveBelow(
-    [lblOverviewTree, cbOverviewTree], chkSnippetsInNewTab, 24
+    [lblOverviewTree, cbOverviewTree], chkSnippetsInNewTab, 12
   );
   TCtrlArranger.MoveBelow(chkSnippetsInNewTab, chkHideEmptySections, 8);
   TCtrlArranger.AlignVCentres(
-    TCtrlArranger.BottomOf(chkHideEmptySections, 24),
+    TCtrlArranger.BottomOf(chkHideEmptySections, 12),
     [lblMainColour, fMainColourBox]
   );
   TCtrlArranger.AlignVCentres(
@@ -187,6 +190,10 @@ procedure TDisplayPrefsFrame.ArrangeControls;
     TCtrlArranger.BottomOf(btnDefColours, 12),
     [lblOverviewFontSize, cbOverviewFontSize]
   );
+  TCtrlArranger.AlignVCentres(
+    TCtrlArranger.BottomOf(cbOverviewFontSize, 8),
+    [lblDetailFontSize, cbDetailFontSize]
+  );
   chkHideEmptySections.Width := Self.Width - 16;
   chkSnippetsInNewTab.Width := Self.Width - 16;
 end;
@@ -201,43 +208,6 @@ procedure TDisplayPrefsFrame.btnDefColoursClick(Sender: TObject);
   fUIChanged := True;
 end;
 
-procedure TDisplayPrefsFrame.cbOverviewFontSizeChange(Sender: TObject);
-var
-  Size: Integer;  // font size entered by user
-begin
-  inherited;
-  // Do nothing if combo box text field cleared
-  if cbOverviewFontSize.Text = '' then
-    Exit;
-  if TryStrToInt(cbOverviewFontSize.Text, Size) then
-  begin
-    if TFontHelper.IsInCommonFontSizeRange(Size) then
-    begin
-      // Combo has valid value entered: update
-      fOverviewFontSize := Size;
-      fUIChanged := True;
-    end
-    else
-    begin
-      // Font size out of range
-      TMessageBox.Error(
-        ParentForm,
-        Format(
-          sErrBadOverviewFontRange,
-          [TFontHelper.CommonFontSizes.Min, TFontHelper.CommonFontSizes.Max]
-        )
-      );
-      cbOverviewFontSize.Text := IntToStr(fOverviewFontSize);
-    end;
-  end
-  else
-  begin
-    // Combo has invalid value: say so
-    TMessageBox.Error(ParentForm, sErrBadOverviewFontSize);
-    cbOverviewFontSize.Text := IntToStr(fOverviewFontSize);
-  end;
-end;
-
 procedure TDisplayPrefsFrame.chkHideEmptySectionsClick(Sender: TObject);
   {Handles clicks on "Hide Empty Sections" check box. Flags UI preferences has
   having changed.
@@ -287,7 +257,7 @@ constructor TDisplayPrefsFrame.Create(AOwner: TComponent);
   fSourceBGColourBox.TabOrder := 5;
   lblSourceBGColour.FocusControl := fSourceBGColourBox;
 
-  PopulateFontSizeCombo;
+  PopulateFontSizeCombos;
 end;
 
 function TDisplayPrefsFrame.CreateCustomColourBox(
@@ -330,7 +300,10 @@ procedure TDisplayPrefsFrame.Deactivate(const Prefs: IPreferences);
   Prefs.SourceCodeBGCustomColours.CopyFrom(
     fSourceBGColourDlg.CustomColors, True
   );
-  Prefs.OverviewFontSize := StrToIntDef(cbOverviewFontSize.Text, 8);
+  // Setting following properties to -1 causes preferences object to use their
+  // default font size
+  Prefs.OverviewFontSize := StrToIntDef(cbOverviewFontSize.Text, -1);
+  Prefs.DetailFontSize := StrToIntDef(cbDetailFontSize.Text, -1);
 end;
 
 function TDisplayPrefsFrame.DisplayName: string;
@@ -344,6 +317,47 @@ function TDisplayPrefsFrame.DisplayName: string;
   Result := sDisplayName;
 end;
 
+procedure TDisplayPrefsFrame.FontSizeChange(Sender: TObject);
+var
+  Size: Integer;  // font size entered by user
+  CB: TComboBox;  // combo box that triggered event
+begin
+  inherited;
+  Assert(Sender is TComboBox,
+    ClassName + '.FontSizeChange: Sender not TComboBox');
+  CB := Sender as TComboBox;
+  // Do nothing if combo box text field cleared
+  if CB.Text = '' then
+    Exit;
+  if TryStrToInt(CB.Text, Size) then
+  begin
+    if TFontHelper.IsInCommonFontSizeRange(Size) then
+    begin
+      // Combo has valid value entered: update
+      CB.Tag := Size;
+      fUIChanged := True;
+    end
+    else
+    begin
+      // Font size out of range
+      TMessageBox.Error(
+        ParentForm,
+        Format(
+          sErrBadOverviewFontRange,
+          [TFontHelper.CommonFontSizes.Min, TFontHelper.CommonFontSizes.Max]
+        )
+      );
+      CB.Text := IntToStr(CB.Tag);
+    end;
+  end
+  else
+  begin
+    // Combo has invalid value: say so
+    TMessageBox.Error(ParentForm, sErrBadOverviewFontSize);
+    CB.Text := IntToStr(CB.Tag);
+  end;
+end;
+
 class function TDisplayPrefsFrame.Index: Byte;
   {Index number that determines the location of the tab containing this frame
   when displayed in the preferences dialog box.
@@ -372,9 +386,12 @@ function TDisplayPrefsFrame.OverviewTreeStateDesc(
   Result := cOTSStartStates[State];
 end;
 
-procedure TDisplayPrefsFrame.PopulateFontSizeCombo;
+procedure TDisplayPrefsFrame.PopulateFontSizeCombos;
 begin
+  cbOverviewFontSize.Clear;
   TFontHelper.ListCommonFontSizes(cbOverviewFontSize.Items);
+  cbDetailFontSize.Clear;
+  TFontHelper.ListCommonFontSizes(cbDetailFontSize.Items);
 end;
 
 procedure TDisplayPrefsFrame.SelectOverviewTreeState(