procedure PaintCover(DestBitmap:TBitmap32;
                     x,y,width,height:integer;
                     perspectiv:single;
                     angle:integer;
                     Reflextion:single;
                     Alpha:integer;
                     picture:TBitmap);

procedure PaintCover(DestBitmap:TBitmap32; x,y,width,height:integer; perspectiv:single;angle:integer; Abdunklung:integer;Alpha:integer; picture:TBitmap32);
var lo,lu,ro,ru:TPoint;
    mo,mu:extended;
    i,j:integer;
    dummy:integer;
    color:tcolor32;
    reflextionlength:integer;
    Points:TArrayOfFixedPoint;
    poly:tPolygon32;
begin


//vier Eckpunkte des Covers berechnen:

lo.x:=x;
lo.Y:=y;
lu.X:=x;
lu.Y:=y+height;
ru.x:=round(lu.x+width*cos(abs(angle)/360*2*Pi));
ru.y:=round(lu.y-perspectiv*height/2*sin(abs(angle)/360*2*Pi));
ro.X:=ru.x;
ro.Y:=round(ru.y-height+perspectiv*height*sin(abs(angle)/360*2*Pi));

if angle<0 then
begin
  dummy:=ro.y;
  ro.y:=lo.y;
  lo.y:=dummy;
  dummy:=ru.y;
  ru.y:=lu.y;
  lu.y:=dummy;
  dummy:=(width-(ro.x-lo.x));
  lo.x:=lo.x+dummy;
  lu.x:=lu.X+dummy;
  ro.x:=ro.X+dummy;
  ru.x:=ru.x+dummy;
end;

//Steigung der oberen und unteren Kante berechnen:


if ((ro.x-lo.X)=0) or ((ru.x-lu.x)=0) then exit; //Cover stehen senkrecht zum Betrachter

  mo:=-(ro.Y-lo.Y)/(ro.x-lo.X);
  mu:=-(ru.Y-lu.Y)/(ru.x-lu.x);


//Bild perspektivisch zeichnen:
DestBitmap.BeginUpdate;

for i:=0 to (ro.X-lo.x) do
 for j:=round(-i*mo) to round((lu.Y-lo.y)+i*mo) do
   begin
     if not (lo.x+i>DestBitmap.Width-1) and not (lo.y+j>DestBitmap.Height-1) then
       if not (lo.x+i<0) and not (lo.y+j<0) then
         begin
          color:=picture.Pixels[round(picture.Width/(ro.x-lo.X)*i), round(picture.Height/((lu.Y-lo.y)+2*i*mo)*(j+i*mo))];
          TColor32Entry(color).A := alpha;
          DestBitmap.SetPixelT(lo.X+i,lo.Y+j,color);
         end;
   end;
  
 //Reflextion berechnen:

for i:=0 to (ro.X-lo.x) do
 begin
  ReflextionLength:=round(((lu.y-lo.y)+(mo*i)));
  if ReflextionLength>0 then
     for j:= 0 to ReflextionLength do
       begin
        if not (lo.x+i>DestBitmap.Width-1) and not (lu.Y+round(mo*i)+j>DestBitmap.Height-1) then
         if not (lo.x+i<0) and not (lu.Y+round(mo*i)+j<0) then
           begin
             color:=DestBitmap.Pixel[lo.X+i,lu.Y+round(mo*i)-j];
             color:=GR32_Blend.Lighten(color,round(-Abdunklung)); //Reflextion ist verdunkeltes und gespiegeltes Original
             //TColor32Entry(color).A := round(alpha*(1-1/ReflextionLength*j)); //Transparente Reflextionen mit AlphaBlending
             DestBitmap.SetPixelT(lo.X+i,lu.Y+round(mo*i)+j,color);
           end;
       end;
 end;



//Rechteck zeichnen:

  poly:=TPolygon32.create;
  poly.Add(fixedpoint(lo.x,lo.Y));
  poly.Add(fixedpoint(lu.x,lu.y));
  poly.Add(fixedpoint(ru.x,ru.y));
  poly.Add(fixedpoint(ro.x,ro.y));
  poly.AntialiasMode:=am32times; //32faches Antialiasing bremst die Darstellung und kann auch deaktiviert werden
  poly.Antialiased:=true;
  poly.Closed:=true;
  poly.DrawEdge(DestBitmap,Color32(20,20,20,255));

  freeandnil(poly);



DestBitmap.EndUpdate;

end;