Mega Code Archive
Png2bmp
<![CDATA[
//www.dronymc.cjb.net
//drony@mynet.com
//icq:266148308
function TdtpPngFormat.LoadImageFromStream(S: TStream; ADIB: TBitmap32;
AMaxSize: TPoint; Page: integer): integer;
var
i, j: integer;
APng: TPngObject;
P: PColor32;
A: PByte;
ABmp: TBitmap;
Canvas: TCanvas;
begin
if Page > 0 then
begin
Result := creIllegalPageNum;
exit;
end;
APng := TPngObject.Create;
ABmp := TBitmap.Create;
try
{Load and assign to the a bitmap}
APng.LoadFromStream(S);
APng.AssignTo(ABmp);
{We now draw the bitmap to our bitmap. This will clear alpha in places where drawn, so we can use it later}
ADib.SetSize(APng.Width, APng.Height);
ADib.Clear(clBlack32);
Canvas := TCanvas.Create;
try
Canvas.Handle := ADib.Handle;
TGraphicAccess(ABmp).Draw(Canvas, Rect(0, 0, ADib.Width, ADib.Height));
finally
Canvas.Free;
end;
{Flip the alpha channel}
P := @ADib.Bits[0];
for i := 0 to ADib.Width * ADib.Height - 1 do
begin
P^ := P^ XOR $FF000000;
inc(P);
end;
{The previous doesn't handle bitwise alpha info, so we do that here}
for i := 0 to APng.Height - 1 do
begin
A := PByte(APng.AlphaScanLine[i]);
if assigned(A) then
begin
P := @ADib.Bits[i * ADib.Width];
for j := 0 to APng.Width - 1 do
begin
P^ := SetAlpha(P^, A^);
inc(P); inc(A);
end;
end
else
break;
end;
{Arriving here means "all ok"}
Result := creAllOK;
finally
APng.Free;
ABmp.Free;
end;
end;
]]>