Grafik drehen

[Bjoerk]

Zitat von OnlyOne:

Danke für die Lösungen aber [..] Wahrscheinlich habe ich irgendwo einen Denkfehler. Bin für alle Lösungen offen

Ja, ist etwas tricky. Man muß dabei berücksichtigen das dein Drehpunkt (Center) nicht der Drehpunkt von SetWorldTransform ist. Hab Dir mal ein paar Methoden rauskopiert.

Ich hoffe damit nicht wieder ein "Vorsagen-Verstoß" begangen zu haben..

Delphi-Quellcode:

type
  TRotationZoomCanvas = class
  private
    procedure SetCanvas(const Value: TCanvas);
  protected
    FCanvas: TCanvas;
    FAngle: double;
    FZoom: double;
    procedure SetRotationZoom(OffsetX, OffsetY: double);
    procedure Reset;
  public
    procedure Draw(X, Y: integer; Graphic: TGraphic);
    procedure StretchDraw(ARect: TRect; Graphic: TGraphic);
    property Canvas: TCanvas read FCanvas write SetCanvas;
    property Angle: double read FAngle write FAngle;
    property Zoom: double read FZoom write FZoom;
  end;

implementation

procedure TRotationZoomCanvas.SetCanvas(const Value: TCanvas);
begin
  FCanvas := Value;
  SetGraphicsMode(FCanvas.Handle, GM_ADVANCED);
  // SetMapMode(FCanvas.Handle, MM_ANISOTROPIC);
  FZoom := 1;
end;

procedure TRotationZoomCanvas.Draw(X, Y: integer; Graphic: TGraphic);
var
  O: TPoint;
begin
  O.X := X + Graphic.Width div 2;
  O.Y := Y + Graphic.Height div 2;
  SetRotationZoom(O.X, O.Y);
  FCanvas.Draw(X - O.X, Y - O.Y, Graphic);
  Reset;
end;

procedure TRotationZoomCanvas.StretchDraw(ARect: TRect; Graphic: TGraphic);
var
  O: TPoint;
begin
  O.X := (ARect.Left + ARect.Right) div 2;
  O.Y := (ARect.Top + ARect.Bottom) div 2;
  SetRotationZoom(O.X, O.Y);
  FCanvas.StretchDraw(Rect(ARect.Left - O.X, ARect.Top - O.Y,
    ARect.Right - O.X, ARect.Bottom - O.Y), Graphic);
  Reset;
end;

procedure TRotationZoomCanvas.Reset;
var
  Angle, Zoom: double;
begin
  Angle := FAngle;
  Zoom := FZoom;
  FAngle := 0;
  FZoom := 1;
  SetRotationZoom(0, 0);
  FAngle := Angle;
  FZoom := Zoom;
end;

procedure TRotationZoomCanvas.SetRotationZoom(OffsetX, OffsetY: double);
var
  Mat: tagXFORM;
  C, S: double;
begin
  C := FZoom * Cos(0.0174532925199433 * FAngle);
  S := FZoom * Sin(0.0174532925199433 * FAngle);
  Mat.eM11 := C;
  Mat.eM12 := S;
  Mat.eM21 := -S;
  Mat.eM22 := C;
  Mat.eDx := OffsetX;
  Mat.eDy := OffsetY;
  SetWorldTransform(FCanvas.Handle, Mat);
end;

..

procedure TCanvasToolsExampleForm.Button1Click(Sender: TObject);
begin
  FRotationZoomCanvas.Canvas := Canvas;
  FRotationZoomCanvas.Zoom := 1.5;
  FRotationZoomCanvas.Angle := 30;
  FRotationZoomCanvas.Draw(100, 100, FBitmap);
end;