From ce83bb5a9157adfb0e65601e5700e3e4ebb98ed1 Mon Sep 17 00:00:00 2001
From: ask <ask@lazarus-ide.org>
Date: Tue, 6 Apr 2010 15:35:21 +0000
Subject: [PATCH] TAChart: Use broadacster/listener to update chart after
 changes in axis transformation

git-svn-id: trunk@24473 -
---
 components/tachart/tachartaxis.pas       |  8 +++++++-
 components/tachart/tatransformations.pas | 21 +++++++++------------
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/components/tachart/tachartaxis.pas b/components/tachart/tachartaxis.pas
index 888d5108e7..002c123656 100644
--- a/components/tachart/tachartaxis.pas
+++ b/components/tachart/tachartaxis.pas
@@ -104,6 +104,7 @@ type
 
   TChartAxis = class(TCollectionItem)
   private
+    FListener: TListener;
     FMarkTexts: TStringDynArray;
     FMarkValues: TDoubleDynArray;
     FSize: Integer;
@@ -323,6 +324,7 @@ end;
 constructor TChartAxis.Create(ACollection: TCollection);
 begin
   inherited Create(ACollection);
+  FListener := TListener.Create(@FTransformations, @StyleChanged);
   FGrid := TChartAxisPen.Create;
   FGrid.OnChange := @StyleChanged;
   FGrid.Style := psDot;
@@ -330,7 +332,6 @@ begin
   FTickColor := clBlack;
   FTickLength := DEF_TICK_LENGTH;
   FTitle := TChartAxisTitle.Create(ACollection.Owner as TCustomChart);
-  //FTransformation.OnChanged := @StyleChanged;
   FVisible := true;
 end;
 
@@ -338,6 +339,7 @@ destructor TChartAxis.Destroy;
 begin
   FTitle.Free;
   FMarks.Free;
+  FListener.Free;
   FGrid.Free;
   inherited;
 end;
@@ -644,7 +646,11 @@ end;
 procedure TChartAxis.SetTransformations(AValue: TChartAxisTransformations);
 begin
   if FTransformations = AValue then exit;
+  if FListener.IsListening then
+    Transformations.Broadcaster.Unsubscribe(FListener);
   FTransformations := AValue;
+  if FTransformations <> nil then
+    Transformations.Broadcaster.Subscribe(FListener);
   StyleChanged(Self);
 end;
 
diff --git a/components/tachart/tatransformations.pas b/components/tachart/tatransformations.pas
index 707448b65f..a4c3858f32 100644
--- a/components/tachart/tatransformations.pas
+++ b/components/tachart/tatransformations.pas
@@ -35,9 +35,7 @@ type
   TAxisTransform = class(TIndexedComponent)
   private
     FEnabled: Boolean;
-    FOnChanged: TNotifyEvent;
     FTransformations: TChartAxisTransformations;
-    procedure SetOnChanged(const AValue: TNotifyEvent);
     procedure SetTransformations(AValue: TChartAxisTransformations);
   protected
     procedure ReadState(Reader: TReader); override;
@@ -57,8 +55,8 @@ type
     function AxisToGraph(AX: Double): Double; virtual;
     function GraphToAxis(AX: Double): Double; virtual;
 
-    property OnChanged: TNotifyEvent read FOnChanged write SetOnChanged;
-    property Transformations: TChartAxisTransformations read FTransformations write SetTransformations;
+    property Transformations: TChartAxisTransformations
+      read FTransformations write SetTransformations;
   published
     property Enabled: Boolean read FEnabled write FEnabled default true;
   end;
@@ -72,6 +70,7 @@ type
 
   TChartAxisTransformations = class (TComponent)
   private
+    FBroadcaster: TBroadcaster;
     FList: TAxisTransformList;
   public
     constructor Create(AOwner: TComponent); override;
@@ -82,6 +81,8 @@ type
   public
     function AxisToGraph(AX: Double): Double;
     function GraphToAxis(AX: Double): Double;
+
+    property Broadcaster: TBroadcaster read FBroadcaster;
   published
     property List: TAxisTransformList read FList;
   end;
@@ -278,8 +279,8 @@ end;
 
 procedure TAxisTransform.Changed;
 begin
-  if Assigned(FOnChanged) then
-    FOnChanged(Self);
+  if Transformations <> nil then
+    Transformations.Broadcaster.Broadcast;
 end;
 
 constructor TAxisTransform.Create(AOwner: TComponent);
@@ -330,12 +331,6 @@ begin
     Move(Index, EnsureRange(AValue, 0, Count - 1));
 end;
 
-procedure TAxisTransform.SetOnChanged(const AValue: TNotifyEvent);
-begin
-  if TMethod(FOnChanged) = TMethod(AValue) then exit;
-  FOnChanged := AValue;
-end;
-
 procedure TAxisTransform.SetParentComponent(AParent: TComponent);
 begin
   if not (csLoading in ComponentState) then
@@ -366,6 +361,7 @@ end;
 constructor TChartAxisTransformations.Create(AOwner: TComponent);
 begin
   inherited Create(AOwner);
+  FBroadcaster := TBroadcaster.Create;
   FList := TAxisTransformList.Create;
 end;
 
@@ -374,6 +370,7 @@ begin
   while List.Count > 0 do
     TAxisTransform(List[List.Count - 1]).Free;
   FList.Free;
+  FBroadcaster.Free;
   inherited;
 end;