source: branches/ByteArray/Devices/FrameBuffer.pas

unit FrameBuffer;

interface

uses
  Classes, SysUtils, Device, Channel, IntMemory, Int;

type
  TScreenMode = (smText, smGraphic);

  { TFrameBuffer }

  TFrameBuffer = class(TDevice)
  private
    FOnChange: TNotifyEvent;
    procedure DoChange;
    function ReadData(Size: TIntSize): TInt;
    function ReadPosition(Size: TIntSize): TInt;
    function ReadWidth(Size: TIntSize): TInt;
    function ReadHeight(Size: TIntSize): TInt;
    function ReadMode(Size: TIntSize): TInt;
    procedure WriteData(Size: TIntSize; Value: TInt);
    procedure WritePosition(Size: TIntSize; Value: TInt);
    procedure WriteWidth(Size: TIntSize; Value: TInt);
    procedure WriteHeight(Size: TIntSize; Value: TInt);
    procedure WriteMode(Size: TIntSize; Value: TInt);
  public
    Memory: TMemory;
    Position: Integer;
    Width: Integer;
    Height: Integer;
    Mode: TScreenMode;
    procedure UpdateMode;
    function GetHandlers: THandlers; override;
    constructor Create;
    destructor Destroy; override;
    property OnChange: TNotifyEvent read FOnChange write FOnChange;
  end;


implementation

{ TFrameBuffer }

procedure TFrameBuffer.DoChange;
begin
  if Assigned(FOnChange) then FOnChange(Self);
end;

function TFrameBuffer.ReadData(Size: TIntSize): TInt;
begin
  Result := Memory.Read(Position, Size);
  Inc(Position, Size);
end;

function TFrameBuffer.ReadPosition(Size: TIntSize): TInt;
begin
  Result := Position;
end;

function TFrameBuffer.ReadWidth(Size: TIntSize): TInt;
begin
  Result := Width;
end;

function TFrameBuffer.ReadHeight(Size: TIntSize): TInt;
begin
  Result := Height;
end;

function TFrameBuffer.ReadMode(Size: TIntSize): TInt;
begin
  Result := Byte(Mode);
end;

procedure TFrameBuffer.WriteData(Size: TIntSize; Value: TInt);
begin
  Memory.Write(Position, Size, Value);
  Inc(Position, Size);
end;

procedure TFrameBuffer.WritePosition(Size: TIntSize; Value: TInt);
begin
  Position := Value;
end;

procedure TFrameBuffer.WriteWidth(Size: TIntSize; Value: TInt);
begin
  Width := Value;
  UpdateMode;
end;

procedure TFrameBuffer.WriteHeight(Size: TIntSize; Value: TInt);
begin
  Height := Value;
  UpdateMode;
end;

procedure TFrameBuffer.WriteMode(Size: TIntSize; Value: TInt);
begin
  Mode := TScreenMode(Integer(Value));
  UpdateMode;
end;

procedure TFrameBuffer.UpdateMode;
begin
  Memory.Size := Width * Height;
  Memory.FillZero;
end;

function TFrameBuffer.GetHandlers: THandlers;
begin
  Result := THandlers.Create;
  Result.ReadHandlers.Add(ReadData);
  Result.ReadHandlers.Add(ReadPosition);
  Result.ReadHandlers.Add(ReadWidth);
  Result.ReadHandlers.Add(ReadHeight);
  Result.ReadHandlers.Add(ReadMode);
  Result.WriteHandlers.Add(WriteData);
  Result.WriteHandlers.Add(WritePosition);
  Result.WriteHandlers.Add(WriteWidth);
  Result.WriteHandlers.Add(WriteHeight);
  Result.WriteHandlers.Add(WriteMode);
end;

constructor TFrameBuffer.Create;
begin
  Memory := TMemory.Create;
  Position := 0;
  Width := 40;
  Height := 25;
  Mode := smText;
  UpdateMode;
end;

destructor TFrameBuffer.Destroy;
begin
  FreeAndNil(Memory);
  inherited;
end;

end.