GDI+ 学习记录(25): 变换 Transform

//比例变化
var
  g: TGPGraphics;
  p: TGPPen;
  rect: TGPRect;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  p := TGPPen.Create(MakeColor(255,255,0,0),0);
  rect := MakeRect(10,10,100,100);

  g.DrawRectangle(p, rect); {原始}

  g.ScaleTransform(2, 0.5); {横向放大、纵向缩小}
  p.SetColor(aclBlue);      {变个颜色看清楚}
  g.DrawRectangle(p, rect); {重绘}
  g.ResetTransform;         {恢复变化, 不然下一个变化将基于现在的状态}

  p.Free;
  g.Free;
end;


//角度变化(旋转)
var
  g: TGPGraphics;
  p: TGPPen;
  rect: TGPRect;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  p := TGPPen.Create(MakeColor(255,255,0,0),0);
  rect := MakeRect(10,10,100,100);

  g.DrawRectangle(p, rect);

  g.RotateTransform(28); {旋转28度角, 正值顺时针、负值逆时针}
  p.SetColor(aclBlue);
  g.DrawRectangle(p, rect);
  g.ResetTransform;

  p.Free;
  g.Free;
end;


//位置变化(移动)
var
  g: TGPGraphics;
  p: TGPPen;
  rect: TGPRect;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  p := TGPPen.Create(MakeColor(255,255,0,0),0);
  rect := MakeRect(10,10,100,100);

  g.DrawRectangle(p, rect);

  g.TranslateTransform(111,111); {移动}
  p.SetColor(aclBlue);
  g.DrawRectangle(p, rect);
  g.ResetTransform;

  p.Free;
  g.Free;
end;