+ Timer component by warleyalex

packages/rtl/timer.pas

@@ -0,0 +1,122 @@
+{
+    This file is part of the Pas2JS run time library.
+    Copyright (c) 2018 by warleyalex <warleyalex@yahoo.com.br>
+
+    See the file COPYING.FPC, included in this distribution,
+    for details about the copyright.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+ **********************************************************************}
+
+{$mode objfpc}
+
+unit timer;
+
+Interface
+
+uses JS, Web, Classes;
+
+type
+  TTimer = class(TComponent)
+  private
+    FEnabled: Boolean;  // True
+    FInterval: Integer; // 1000
+    FOnTimer: TNotifyEvent;
+    FID: Integer;
+    procedure SetEnabled(Value: Boolean);
+    procedure SetInterval(Value: Integer);
+  protected
+    function DesignEvent: Boolean; virtual;
+    procedure DoUpdateTimer; virtual;
+    procedure DoClearTimer; virtual;
+    procedure DoTimer; virtual;
+  public
+    constructor Create(AOwner: TComponent); override;
+    destructor Destroy; override;
+  published
+    { Specifies whether the timer is enabled }
+    property Enabled: Boolean read FEnabled write SetEnabled default True;
+    { Specifies the interval, in milliseconds, between timer events }
+    property Interval: Integer read FInterval write SetInterval default 1000;
+    property Tag;
+    { Fired when the timer interval has elapsed }
+    property OnTimer: TNotifyEvent read FOnTimer write FOnTimer;
+  end;
+
+implementation
+
+{ TTimer }
+
+constructor TTimer.Create(AOwner: TComponent);
+begin
+  inherited Create(AOwner);
+  FEnabled := True;
+  FInterval := 1000;
+  DoUpdateTimer;
+end;
+
+destructor TTimer.Destroy;
+begin
+  Enabled := False;
+  inherited Destroy;
+end;
+
+function TTimer.DesignEvent: Boolean;
+begin
+  Result := False;
+end;
+
+procedure TTimer.DoUpdateTimer;
+begin
+  FID := window.setInterval(@DoTimer, FInterval);
+end;
+
+procedure TTimer.DoClearTimer;
+begin
+  if (FID <> 0) then
+  begin
+    window.clearInterval(FID);
+    FID := 0;
+  end;
+end;
+
+procedure TTimer.SetEnabled(Value: Boolean);
+begin
+  if (Value <> FEnabled) then
+  begin
+    if Value then
+      DoUpdateTimer
+    else
+      DoClearTimer;
+    FEnabled := Value;
+  end;
+end;
+
+procedure TTimer.SetInterval(Value: Integer);
+begin
+  if (Value <> FInterval) then
+  begin
+    if Enabled then
+    begin
+      Enabled := False;
+      try
+        FInterval := Value;
+      finally
+        Enabled := True;
+      end;
+    end
+    else
+      FInterval := Value;
+  end;
+end;
+
+procedure TTimer.DoTimer;
+begin
+  if Assigned(FOnTimer) then
+    FOnTimer(Self);
+end;
+
+end.