ADD: [Differ] Paint background option

src/fdiffer.lfm

@@ -1,7 +1,7 @@
 object frmDiffer: TfrmDiffer
-  Left = 282
+  Left = 402
   Height = 379
-  Top = 83
+  Top = 82
   Width = 760
   Caption = 'Compare files'
   ClientHeight = 359
@@ -314,6 +314,14 @@ object frmDiffer: TfrmDiffer
         Action = actIgnoreCase
         AutoCheck = True
       end
+      object miDivider4: TMenuItem
+        Caption = '-'
+      end
+      object miPaintBackground: TMenuItem
+        Action = actPaintBackground
+        AutoCheck = True
+        OnClick = actPaintBackgroundExecute
+      end
       object miDivider3: TMenuItem
         Caption = '-'
       end
@@ -354,9 +362,11 @@ object frmDiffer: TfrmDiffer
       end
       object miFirstDiff: TMenuItem
         Action = actFirstDiff
+        OnClick = actFirstDiffExecute
       end
       object miLastDiff: TMenuItem
         Action = actLastDiff
+        OnClick = actLastDiffExecute
       end
     end
   end
@@ -420,6 +430,12 @@ object frmDiffer: TfrmDiffer
       Caption = 'Binary'
       OnExecute = actBinaryCompareExecute
     end
+    object actPaintBackground: TAction
+      AutoCheck = True
+      Caption = 'Paint Background'
+      Checked = True
+      OnExecute = actPaintBackgroundExecute
+    end
   end
   object ImageList: TImageList
     Height = 22

src/fdiffer.lrt

@@ -3,6 +3,7 @@ TFRMDIFFER.MNUFILE.CAPTION=File
 TFRMDIFFER.MISAVE.CAPTION=Save
 TFRMDIFFER.MNUEDIT.CAPTION=Edit
 TFRMDIFFER.MNUOPTIONS.CAPTION=&Options
+TFRMDIFFER.MIDIVIDER4.CAPTION=-
 TFRMDIFFER.MIDIVIDER3.CAPTION=-
 TFRMDIFFER.MIKEEPSCROLLING.CAPTION=Keep Scrolling
 TFRMDIFFER.MNUACTIONS.CAPTION=&Actions
@@ -20,3 +21,4 @@ TFRMDIFFER.ACTIGNOREWHITESPACE.CAPTION=Ignore Blanks
 TFRMDIFFER.ACTKEEPSCROLLING.CAPTION=actKeepScrolling
 TFRMDIFFER.ACTCANCELCOMPARE.CAPTION=Cancel
 TFRMDIFFER.ACTBINARYCOMPARE.CAPTION=Binary
+TFRMDIFFER.ACTPAINTBACKGROUND.CAPTION=Paint Background

src/fdiffer.pas

@@ -15,6 +15,7 @@ type
 
   TfrmDiffer = class(TForm)
     actBinaryCompare: TAction;
+    actPaintBackground: TAction;
     actStartCompare: TAction;
     actFirstDiff: TAction;
     actIgnoreCase: TAction;
@@ -31,6 +32,8 @@ type
     edtFileNameRight: TFileNameEdit;
     ImageList: TImageList;
     MainMenu: TMainMenu;
+    miPaintBackground: TMenuItem;
+    miDivider4: TMenuItem;
     miBinaryCompare: TMenuItem;
     miKeepScrolling: TMenuItem;
     miDivider3: TMenuItem;
@@ -74,6 +77,7 @@ type
     procedure actFirstDiffExecute(Sender: TObject);
     procedure actLastDiffExecute(Sender: TObject);
     procedure actNextDiffExecute(Sender: TObject);
+    procedure actPaintBackgroundExecute(Sender: TObject);
     procedure actPrevDiffExecute(Sender: TObject);
     procedure actStartCompareExecute(Sender: TObject);
     procedure actKeepScrollingExecute(Sender: TObject);
@@ -229,6 +233,20 @@ begin
   end;
 end;
 
+procedure TfrmDiffer.actPaintBackgroundExecute(Sender: TObject);
+begin
+  if actPaintBackground.Checked then
+    begin
+      SynDiffEditLeft.PaintStyle:= psBackground;
+      SynDiffEditRight.PaintStyle:= psBackground;
+    end
+  else
+    begin
+      SynDiffEditLeft.PaintStyle:= psForeground;
+      SynDiffEditRight.PaintStyle:= psForeground;
+    end
+end;
+
 procedure TfrmDiffer.actPrevDiffExecute(Sender: TObject);
 var
   Line: Integer;

src/usyndiffcontrols.pas

@@ -14,6 +14,9 @@ const
   clPaleRed  : TColor = $AAAAFF;
   clPaleBlue : TColor = $FFAAAA;
 
+type
+  TPaintStyle = (psForeground, psBackground);
+
 type
 
   { TSynDiffGutterLineNumber }
@@ -71,12 +74,14 @@ type
 
   TSynDiffEdit = class(TCustomSynEdit)
   private
+    FPaintStyle: TPaintStyle;
     FDiff: TDiff;
     FSpecialLineMarkupEvent: TSpecialLineMarkupEvent;
     FDiffCount: Integer;
   private
     function GetDiffCount: Integer;
     function GetDiffKind(Index: Integer): TChangeKind;
+    procedure SetPaintStyle(const AValue: TPaintStyle);
   protected
     procedure SpecialLineMarkupEvent(Sender: TObject; Line: Integer;
                                      var Special: boolean; AMarkup: TSynSelectedColor);
@@ -84,6 +89,7 @@ type
     constructor Create(AOwner: TComponent); override;
     procedure BeginCompare(ADiff: TDiff);
     procedure EndCompare(ADiffCount: Integer);
+    property PaintStyle: TPaintStyle read FPaintStyle write SetPaintStyle;
     property Diff: TDiff read FDiff write FDiff;
     property DiffKind[Index: Integer]: TChangeKind read GetDiffKind;
     property DiffCount: Integer read GetDiffCount;
@@ -119,20 +125,45 @@ begin
     end;
 end;
 
+procedure TSynDiffEdit.SetPaintStyle(const AValue: TPaintStyle);
+begin
+  if FPaintStyle <> AValue then
+  begin
+    FPaintStyle := AValue;
+    Invalidate;
+  end;
+end;
+
 procedure TSynDiffEdit.SpecialLineMarkupEvent(Sender: TObject; Line: Integer;
   var Special: boolean; AMarkup: TSynSelectedColor);
+var
+  Kind: TChangeKind;
+  LineColor: TColor;
 begin
-  AMarkup.Foreground:= clWindowText;
-  Special:= (DiffCount <> 0);
+  if Line >= DiffCount then Exit;
 
-  if Special and (Line < DiffCount) then
-    with AMarkup do
-    case DiffKind[Line-1] of
-      ckNone:   Background := clWhite;
-      ckModify: Background := clPaleBlue;
-      ckDelete: Background := clPaleRed;
-      ckAdd:    Background := clPaleGreen;
+  Kind:= DiffKind[Line - 1];
+  Special:= (Kind <> ckNone);
+
+  if Special then
+  with AMarkup do
+  begin
+    case Kind of
+      ckModify: LineColor := clPaleBlue;
+      ckDelete: LineColor := clPaleRed;
+      ckAdd:    LineColor := clPaleGreen;
     end;
+    if FPaintStyle = psForeground then
+      begin
+        Foreground := LineColor;
+        Background := clWindow;
+      end
+    else
+      begin
+        Foreground:= clWindowText;
+        Background := LineColor;
+      end;
+  end;
 end;
 
 procedure TSynDiffEdit.BeginCompare(ADiff: TDiff);