Hi, I'm working with a library that let me get a pointer to an UInt8 array containing the pixels of an image.

To show the image on screen, using Lazarus, I must know the Red,Green,Blue and Alpha values of each pixel (am I right?), how can I convert each byte of the UInt8 array to RGBA?

Thanks in advance,

It depends on the pixel format which the image uses. After you read them you can get a TColor with:

function RGBToColor(R, G, B: Byte): TColor;

from unit Graphics

Note that TColor doesn't support Alpha

Let me answer to myself.

I didn't know that I can use lBuffer as an array, so, the index 0 -> Red, 1 -> Green, 2 -> Blue, 3 -> Alpha.

Here's how a buffer can be paint on a form using TBGRABitmap:

lBmp := TBGRABitmap.Create(FImgWidth, FImgHeight);
try
  for y := 0 to lBmp.Height-1 do
  begin
    p := lBmp.Scanline[y];
    for x := 0 to lBmp.Width-1 do
    begin
      p^.red := lBuffer[0];
      p^.green := lBuffer[1];
      p^.blue := lBuffer[2];
      p^.alpha := lBuffer[3];
      inc(p);
      inc(lBuffer);
    end;
  end;
  // Self is a TForm
  lBmp.Draw(Self.Canvas, 0, 0);
finally
  lbmp.Free;
end;