Progressbar färben?

[DeddyH]

Mal eine ganz simple Komponente ohne irgendwelche Panels oder Images:

Delphi-Quellcode:

type
  TMyProgress = class(TGraphicControl)
  private
    FBitmap: TBitmap;
    FPosition: integer;
    procedure SetPosition(const Value: integer);
  protected
    procedure Paint; override;
  public
    procedure SetBounds(ALeft, ATop, AWidth, AHeight: integer); override;
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    property Position: integer read FPosition write SetPosition;
  end;

...

//Code von delphi.about.com kopiert und leicht angepasst, ist ja nur ein Beispiel
procedure GradHorizontal(Canvas: TCanvas; Rect: TRect;
  FromColor, ToColor: TColor);
var
  X: integer;
  dr, dg, db: Extended;
  C1, C2: TColor;
  r1, r2, g1, g2, b1, b2: Byte;
  R, G, B: Byte;
  cnt: integer;
begin
  C1 := FromColor;
  r1 := GetRValue(C1);
  g1 := GetGValue(C1);
  b1 := GetBValue(C1);
  C2 := ToColor;
  r2 := GetRValue(C2);
  g2 := GetGValue(C2);
  b2 := GetBValue(C2);
  dr := (r2 - r1) / Rect.Right - Rect.Left;
  dg := (g2 - g1) / Rect.Right - Rect.Left;
  db := (b2 - b1) / Rect.Right - Rect.Left;
  cnt := 0;
  for X := Rect.Left to Rect.Right - 1 do
    begin
      R := r1 + round(dr * cnt);
      G := g1 + round(dg * cnt);
      B := b1 + round(db * cnt);
      Canvas.Pen.Color := RGB(R, G, B);
      Canvas.MoveTo(X, Rect.Top);
      Canvas.LineTo(X, Rect.Bottom);
      inc(cnt);
    end;
end;

constructor TMyProgress.Create(AOwner: TComponent);
begin
  inherited;
  FBitmap := TBitmap.Create;
  Width := 200;
  Height := 20;
end;

destructor TMyProgress.Destroy;
begin
  FBitmap.Free;
  inherited;
end;

procedure TMyProgress.Paint;
var
  AWidth: integer;
begin
  inherited;
  AWidth := MulDiv(FPosition, Width, 100);
  Canvas.CopyRect(Rect(0, 0, AWidth, Height), FBitmap.Canvas,
    Rect(0, 0, AWidth, Height));
end;

procedure TMyProgress.SetBounds(ALeft, ATop, AWidth, AHeight: integer);
begin
  inherited;
  FBitmap.Width := AWidth;
  FBitmap.Height := AHeight;
  GradHorizontal(FBitmap.Canvas, Rect(0, 0, FBitmap.Width, FBitmap.Height),
    RGB(255, 50, 50), RGB(50, 255, 50));
  Invalidate;
end;

procedure TMyProgress.SetPosition(const Value: integer);
begin
  FPosition := Value;
  Invalidate;
end;

Im Gegensatz zum Original gibt Position hier den Fortschritt in % an, aber das lässt sich ja umschreiben.